Dorado Loss Scenario: Difference between revisions

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<div style="text-align: justify;"><span style="color:#00008B">TEMPORARY NOTE: Please bear with us as we formulate this page. We want to make it right, and are experimenting with the style of the page. Standby for substantial changes in format as we work to that end. Thank you for your patience.


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==Executive Summary (aka "Bottom line up front")==
<div style="text-align: justify;"><span style="color:#00008B">The USS Dorado Project team believes that Dorado was lost due to a friendly fire incident in the central Caribbean on the night of October 12, 1943. Her wreck site and final resting place likely is in the vicinity of that attack. Our case is spelled out below.
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==Background: Loss scenarios, facts, & other data==
===Introduction===
<div style="text-align: justify;"><span style="color:#00008B">Until the wreck site of Dorado is found, no one, including the members of this team, can say definitively what actually happened to Dorado and her crew. The case that we will present below is based on meticulous research in official [[Dorado documents list|'''Navy documents''']], especially excerpts from the two official inquiries into her loss. It is as fact based as we can possibly make it at this time. In order to round out the narrative, there are times in which Thaddeus and the team have used informed speculation based on years of research and personal experience. Every effort has been made to keep speculation to a minimum. There are times in which the narrative gets rather vague, and that is because no verifiable information about those periods exist. The team used first hand personal experience in submarine operations to help fill in the gaps. An example would be the period of Dorado's transit south through the Atlantic.
Another important note: the authors made the conscious decision to use the 12 hour time and month/day/year date format familiar to the American public. Since the majority of our audience will be civilans, we shied away from using a military or European time/date format in order to prevent confusion. Thank you for your understanding in this matter.
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===Possible causes for Dorado's loss===
<div style="text-align: justify;"><span style="color:#00008B">In developing the loss scenario, the authors considered all possible and realistic causes for her loss. We distilled the causes down to five possibilities. Each of these potential causes were extensively studied by the team and given a probability ranking. Each will be explained in detail below.
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====Weather====
<div style="text-align: justify;"><span style="color:#00008B">The Gato-class submarines were very good sea boats, when compared to other submarines. They could handle heavy weather with relative ease on the surface, although it would still be a rough ride for the crew. An example is the [[192a|'''USS Sailfish (SS-192)''']]. She was a [[Salmon/Sargo Class|'''Salmon/Sargo-class''']] boat and slightly smaller than Dorado, but endured a typhoon off the southern coast of Japan [https://www.history.navy.mil/research/histories/ship-histories/danfs/s/sailfish-i.html '''while attacking a Japanese task force''']. Pushing through "mountainous" seas with zero visibility, Sailfish frequently took solid water over the bridge, but her crew pushed on and eventually sank an aircraft carrier. Sailfish and other submarines proved the sea worthiness of the fleet submarine design.
A meteorologist/aeroligist from the Office of the Chief of Naval Operations testified at the Court of Inquiry and stated that Dorado did not encounter any adverse weather during her entire transit from New London. The only disturbance of note was a tropical depression that originated in the vicinity of St. Lucia in the Lesser Antilles far to the east sometime on the 11th of October, moving slowly northwest. It would have passed over Puerto Rico and the Dominican Republic on the night of October 13-14, well after the Dorado would have passed through that area.
In fact, aircraft observations of the weather conditions in the central Caribbean on the night of October 12 stated that the sea was moderate, with visibility at eight miles and a wind of eight knots. It did state that there were "numerous squalls" in the area, but those rain showers would have not affected Dorado in any meaningful way.
It is the opinion of the authors that the weather conditions were will within the capability of Dorado to successfully navigate, and that the weather played no part in her loss.
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====Mechanical Failure or Operational Accident====
<div style="text-align: justify;"><span style="color:#00008B">Operating a submarine at sea, even in peacetime, is an exceedingly dangerous evolution. Operating under the surface of the ocean, in pressures of several hundred pounds per square inch, greatly complicates the otherwise well known process of taking a ship to sea. Since 1900, the United States Navy alone has suffered 14 peacetime accidents that resulted in the submarine sinking to the bottom. In WW II the USN lost 52 submarines, seven of which were due to non-enemy related accidents. In addition to these losses, there have been dozens of incidents in which lives were lost and the submarine damaged, but in which neither the boat nor significant portions crew were lost. It is distinctly possible that Dorado was lost as a result of one of these circumstances. Mechanical failure or operational accidents can take many forms, and we have listed some common (but obviously not all) scenarios below, along with an assessment of their probability.
*Stern planes jam dive - The stern diving planes, fashioned like horizontal rudders and located aft of the propellers, are used to control the angle of the boat while it is submerged. A failure of the mechanical or hydraulic systems that control and operate the planes could lead them to become stuck in the full dive position, pushing the boat into a steep dive and rendering it uncontrollable. Example: [https://www.ussvicb.org/poems-stories/A%20Summary%20of%20Findings%20Which%20Caused.pdf '''Chopper (SS-342), 1969''']. Probability: very low. Dorado was a new boat and had been extensively tested and inspected prior to departure.
*Valve failure - If a valve fails to operate or structurally fails under submergence pressure, rapid and possibly uncontrollable flooding can occur. Example: [https://pigboats.com/index.php?title=Notable_Submarine_Accidents#Squalus_(SS-192),_Equipment_failure_during_a_test_dive,_May_23,_1939 '''Squalus (SS-192), 1939''']. Probability: very low, for the same reasons listed above.
*Battery explosion and fire - Dorado was equipped with two 126-cell lead acid storage batteries, used to provide electricity to electric motors for submerged propulsion. The batteries have to be periodically recharged using the diesel generator sets, and this process is tricky and dangerous if not closely monitored and regulated. When charging, the battery cells can generate extremely flammable hydrogen gas, which if it builds up to high levels can generate an explosion. Related to this is the fact that the batteries can also generate very lethal chlorine gas if sea water is allowed to get into the cells. Every once in a while, this process goes wrong, with disastrous results. Example: [https://archive.navalsubleague.org/2014/arctic-sea-disaster '''Cochino (SS-345), 1949''']. Probability: medium to low. This is a well practiced procedure that the crew is thoroughly trained for. Most submarines charge their batteries several times a day without incident.
*Collision - A collision involving a submarine usually ends up in disaster for the sub. It will sink quickly due to its relatively low reserve buoyancy. Example: [https://pigboats.com/index.php?title=Notable_Submarine_Accidents#S-51_(SS-162),_Collision_with_merchant_ship,_September_25,_1925 '''S-51 (SS-162) collision, 1925'''.] Probability: very low. No reported collisions occurred anywhere along Dorado's route.
*Hull structural failure - Sometimes a submarine's hull can structurally fail under submergence compression due to age, structural failure, or due to unknown damage. The results are usually catastrophic. Example: [[S-28|'''S-28 (SS-133)''']]. Probability: negligible. Dorado was a brand new boat and had been fully tested to its maximum rated depth.
Any of these scenarios is indeed a possible explanation for Dorado's loss, and they can't be ''definitively'' ruled out until the wreck is found and surveyed. However, the authors are confident that none of them are the ''precipitating event'' that caused her loss, for reasons put forth throughout this page.
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====Attack by a U-boat====
<div style="text-align: justify;"><span style="color:#00008B">German U-boats were a known threat off of the Atlantic coast of the U.S. in 1943. U.S. submarines transiting to Panama were on constant alert, and some boats were detailed to anti U-boat patrols along the route. [[204|'''USS Mackerel (SS-204)''']] was actually [https://www.history.navy.mil/research/histories/ship-histories/danfs/m/mackerel-i.html '''fired upon by a U-boat off Virginia in April, 1942''']. She narrowly avoided the torpedoes and then counter-attacked with her own, but was not successful. Although German activity in the western Atlantic and Caribbean had peaked the previous year, U-boats were still operating in the area in the summer and fall of 1943.<br><br>
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[[File:Type VIID U-boat.jpg|right|thumb|250px|Type VIID U-boat minelayer]]
<div style="text-align: justify;"><span style="color:#00008B">At the time of Dorado's loss, two U-boats were in the general vicinity. [https://en.wikipedia.org/wiki/German_submarine_U-518 '''U-518'''], a Type IXC long range boat, was operating in the Gulf of Mexico, 870 nautical miles to the northwest and can be ruled out as having played a part. [https://en.wikipedia.org/wiki/German_submarine_U-214 '''U-214'''], a Type VIID minelaying boat was in the central Caribbean on her seventh war patrol. She was on a mission to lay mines near the entrance to the Panama Canal (see below) and in fact had already done so and was on her return leg to Germany. U-214 survived this patrol and successfully returned to Germany. After the war her log was examined. There was no entry describing a torpedo attack on a U.S. submarine, nor any entry describing even the sighting of a submarine.
For these and other reasons outlined here, a direct attack by an enemy submarine on the Dorado can be definitively ruled out as a cause of her loss.
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====Mine strike====
<div style="text-align: justify;"><span style="color:#00008B">The authors considered the possibility of Dorado striking a mine along her route. This has been a leading theory in the past regarding the loss of Dorado. German U-boats were known to undertake mine laying missions off the U.S. coast. Mine fields can only be laid in relatively shallow (2000 feet or less) waters near shore. There were no known minefields in the Long Island/Block Island Sound area at the beginning of the voyage; indeed there were no reports of mine detonations in that area in October. The deep water that made up the majority of Dorado's route to Panama was not conducive to mining. Therefore these areas can be ruled out.<br><br>
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[[File:SMA mine new.jpg|left|thumb|175px|German Type SMA mine.]]
<div style="text-align: justify;"><span style="color:#00008B">However, as stated above, U-214 was on a mission to lay a mine field near the Caribbean entrance to the Panama Canal that October. The specialized mine layer was perfectly suited for the job, although she was at the limit of her range to do so. U-214 was equipped with five vertical mine tubes in a compartment immediately aft of the control room. These tubes were capable of holding three mines each, and U-214 carried a total of 15 Type SMA mines on this patrol, in addition to her normal complement of 14 torpedoes. The mines were laid dropping them out of the bottom of the tube, as shown in the illustration above. The process could be accomplished while the boat was submerged. In early October she laid these mines in an west to east slightly curved linear pattern, roughly eight nautical miles north of the Cristobal/Colon harbor breakwater. This area laid astride the very busy shipping lanes to and from the canal and was ideal to disrupt shipping patterns and sink ships. Dozens of ships, both civilian and military passed through this area daily. The SMA was a moored magnetic influence mine, meaning the disruption of the Earth's magnetic field as a steel-hulled ship passed near would trigger the detonator. It had a 772 lb (350 kg) explosive charge and was a deadly weapon.
Once dropped from the tube the weapon would sink to the bottom. A hydrostatic switch would then activate, releasing the upper explosive mine from its weighted base, with the mine floating up on its cable to a pre-set depth where it would activate. It was supposed to remain moored via the cable to its base until detonated by a passing ship. The mines would be laid one at a time, at the prescribed interval to achieve the desired field shape. The delay in activation was intentional, allowing the U-boat to open enough distance so that the mine would not detonate from the effects of the U-boat's hull.
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[[File:Dorado German minefield near Panama 1943.jpg|right|thumb|400px|<small>Graphic ©Thaddeus Weaver, 2025</small>]]
<div style="text-align: justify;"><span style="color:#00008B">The graphic at right shows some key data points when considering the mine strike scenario. The points in red labeled 1 to 15 are the locations of each mine plant, taken directly from the U-214's log. As you can see the field was laid astride the shipping lane to the entrance to the canal, which is in Limon Bay just to the west of Colòn and Cristobal near the bottom of the chart. Any ships approaching or departing the canal would have to pass through the minefield.
The points in black labeled A through J are the reported locations of the mines when they were detected and swept by U.S. forces. The data in the lower left gives the dates when the mines were found. The discrepancies in location are to be expected. U-214's plotting of the field was likely not as precise as they recorded it due to the limitations of navigation in that period (no GPS or precise electronic navigation systems). The same can be said for the recorded U.S. locations. It should also be noted that mine "A" (U.S.) does not necessarily correspond to mine "1" (German), etc.
There are several other very important data points on this chart. First, the first mine was discovered and swept by U.S. forces on October 9, Just three days after Dorado's departure from New London and while she was still well out in the Atlantic on her transit (see below). The presence of the mine field was already known ''prior'' to Dorado's scheduled arrival and it was actively being swept and neutralized.
Second, the prevailing currents in the area were to the east-northeast. Any mines that broke free of their mooring cables or had their cables cut by the minesweepers would have drifted on the currents in that direction, well out of the path that Dorado was following to Point George. Indeed, mine "I", swept on October 29 but not immediately destroyed, drifted northeast past Manzillo Point before it was finally neutralized.
Third, and most importantly, Point George, Dorado's final navigation waypoint and the spot she was to rendezvous with the USN destroyer on the surface, was seven nautical miles ''north'' of the northern most boundary of the minefield. Dorado could not possibly have contacted one of U-214's mines as they were all laid to the south of the rendezvous position. After that point she was to proceed on the surface under escort of the destroyer and the two ships would have transited through an ''already swept lane'' to the submarine base at Coco Solo. Other than the detonations of the mines by the minesweepers as they were being neutralized, no underwater explosions were reported by any of the numerous ships in the area, which would have been an indication that a submarine had contacted a mine.
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[[File:Dorado German EMS 1 mine.jpg|left|thumb|100px|German type EMS 1 mine.]]<div style="text-align: justify;"><span style="color:#00008B">There is one other mine theory to be considered. U-214 also carried [http://www.navweaps.com/Weapons/WAMGER_Mines.php#EMS '''four small type EMS 1 floating mines''']. These small mines were designed to be deployed over the side by hand by a crewman on the aft deck while the boat was on the surface. They had a small 24 to 30 lb. explosive charge and were intended to be deployed in a shipping lane where a ship could contact one by running into it.
At 7:35 pm on the evening of October 12, 1943 the U-214 deployed one of these mines in a position southwest of Dorado, and unknowingly, generally in the path Dorado needed to take to get to Point George. The datum point for this deployment was roughly 40 nautical miles south-southwest from Dorado's position at the time, and to the left of her plotted track. The prevailing currents in the area would have the EMS mine drift on a divergent course east-northeast and out of the Dorado's way.
Assuming that Dorado made it that far, the chances of her running into this small, singular floating mine in the vastness of the central Caribbean is infinitesimal at best. While this remains a viable theory, we rate its probability as negligible to zero.<br><br><br><br><br><br>
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In summary, there is ''ZERO'' chance that Dorado struck one of the mines laid by U-214 in early October off the entrance to the canal, and a ''NEGLIGIBLE'' chance that she struck the lone floating type EMS 1 mine deployed by U-214 on the evening of October 12, 1943. Dorado's loss to a mine strike is therefore highly improbable.
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====Friendly fire====
<div style="text-align: justify;"><span style="color:#00008B">World War II was warfare on a nearly unimaginable scale, fought by well equipped and highly motivated forces. The sheer scope of the conflict, combined with the enormous number of combatants, makes it inevitable that the [https://en.wikipedia.org/wiki/Fog_of_war '''"fog of war"'''] will eventually creep in, dangerously confusing the battlefield. That fog of war resulted in numerous "friendly fire" incidents, in which forces mistakenly fired upon their own side, thinking they were the enemy.
In the U.S. Submarine Service there is precedent for this. Several incidents occurred throughout the war. The famous [https://www.navsource.net/archives/08/08257.htm '''Harder (SS-257)'''] was attacked by friendly aircraft ''in the Caribbean'' on May 2, 1943. She escaped without damage and immediately reported the incident. [https://www.navsource.net/archives/08/08197.htm '''Seawolf (SS-197)'''] was lost on October 3, 1944 after being mistakenly attacked by the [https://www.navsource.net/archives/06/403.htm '''USS Richard M. Rowell (DE-403)'''] off Morotai island in the Pacific.
An incident occurred on the night of October 12, 1943 in the central Caribbean in which a USN PBM-3S Mariner patrol aircraft bombed a surfaced submarine. Based on her orders, Dorado was likely in the area at the time of this incident. The authors believe that this is the ''precipitating event'' that lead to the Dorado's loss. Our scenario explaining this theory is laid out in detail below. 
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==The Loss Scenario==
<div style="text-align: justify;"><span style="color:#00008B">What we present below is the scenario as we believe it to be ''at this time'', and it admittedly is ''not the only possibility''. Subsequent research and/or actually finding the wreck site has the potential to radically alter the story. Thank you for your interest. If you have questions or comments, please direct them to [mailto:ussdoradoproject@gmail.com '''ussdoradoproject@gmail.com'''].
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===The Departure===
[[File:Flasher Mod 3 photo 1.jpg|left|thumb|400px|<small>USS Flasher (SS-249), Dorado's sister boat, on sea trials in 1943. Dorado would have been configured very close to this when she left for war. NARA photo #80-G-450241 via Navsource.net.</small>]]
<div style="text-align: justify;"><span style="color:#00008B">On the morning of October 6, 1943, Dorado backed smartly out of her slip at Submarine Base New London, Groton, CT., put on some left rudder, and swung her stern to the north and up river. Expertly timing the swing, LCDR Schneider, present on the bridge with several other crewmen, ordered zero rudder and all stop. He then ordered "all ahead two thirds" and Dorado began her trip down the Thames River, headed to Long Island Sound and eventually the Atlantic Ocean.
She passed under the U.S. Route 1 bridge, with the venerable structure lifted open to allow the boat to pass underneath. She passed the main Electric Boat facility on her port beam, and a little further downstream she passed the Victory Yard where she was built. Men and women toiling in the cool October air on Dorado's sister subs paused for a moment, proudly acknowledging their handiwork as the submarine passed. They wished her luck as she headed off to war.
The crew was experiencing a mixed set of emotions. They had come to enjoy their stay in Connecticut and had a deep appreciation for the hard work put forth on their behalf by the Electric Boat personnel. Friendships had developed with the workers that the men valued. Some of the crew had brought family members to the Groton/New London area and they were now leaving that all behind; a touch of sadness prevailed as they sailed down the Thames River. There was also a palpable sense of anxiety as they pushed the bow of the boat into the unknown. The experienced men knew of the combat that laid ahead, the inexperienced men put on a brave face as they tamped down their fears. All of that was tempered by the excitement of finally moving forward. They were well trained and confident in themselves and their shipmates, and despite lingering anxiety they eagerly anticipated the adventure that laid ahead.
Fishing vessels hailed her as she passed the mouth of the Thames and Schneider rang up an ahead standard bell with turns for 14 knots. The bridge watch team kept a wary eye on the Fisher's Island and Montauk ferries as they passed, with a little maneuvering left and right intended to keep the ferries at a safe distance. Clearing Fisher's Island she made a slight turn to the southeast, putting her on course to pass down the middle between Montauk Point on her starboard side and Block Island on her port. Down below in the conning tower and control room the Quartermasters and the Navigator were busy piloting the submarine, shooting bearings with the periscope to land-based navigation aids, using those bearings to triangulate their position on the chart. With Montauk Point on their starboard quarter, they took their "point of departure", i.e. the last confirmed land-based navigational fix, and headed out into the blue Atlantic.
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===The Voyage===
[[File:Dorado route 6 to 14 Oct 43.jpg|left|thumb|400px|<small>Graphic ©Thaddeus Weaver, 2025</small>]]
<div style="text-align: justify;"><span style="color:#00008B">Dorado's voyage orders were referred to by the Navy as a Movement Order, or MOVORD. Dorado's MOVORD for the initial leg contained seven waypoints, Able to George. They would route her out into the Atlantic and south towards the Caribbean. Her destination was Submarine Base Coco Solo, on the Atlantic side of the Panama Canal near the city of Colon. She would briefly stop there to refuel and reprovision prior to her transit through the Panama Canal and the second leg out across the Pacific to Hawaii.
The final waypoint was Point George, 15 nautical miles (NM) north of the Cristobal Breakwater, a structure that defined the harbor for Cristobal and Colon. At George the Dorado was to rendezvous with a U.S. destroyer, who would escort Dorado on the surface the last few miles to the submarine base. This rendezvous was supposed to happen at 11:00 local on the morning of October 14. This date/time is very important for several reasons:<br>
* Being escorted into the harbor by the destroyer would prevent Dorado from being mistaken for a German submarine (known to be operating in the Caribbean) and being fired upon by friendly forces. Being early or late for the rendezvous was frowned upon, as it would cause serious tactical, operational, and logistical problems that the Navy wanted to avoid.<br><br>
* Traffic through the canal was very high, and specific times were assigned to ships for passage so that the possibility of traffic jams was avoided. If Dorado missed her transit time, it would delay her voyage all the way to Pearl Harbor and the war zone and exacerbate the operational and logistical issues previously mentioned.<br><br>
* The date/time of her arrival at Point George also dictated the speed of her transit, known properly as her "speed of advance" (SOA). To make Point George on time her SOA was 14 knots. This was also a fuel efficient speed and was well within her maximum surface speed of 21 knots. However, it also dictated that Dorado make the transit mostly on the surface, as her maximum submerged speed was only eight knots. LCDR Schneider had the discretion to submerge as he saw fit for drills and training, but he had to maintain the average speed of 14 knots in order to make George on time.
Dorado would also make the voyage under a condition known as "radio silence". This was a procedure in which Dorado was not to use her radio for routine transmissions, out of a concern that German submarines in the area might use those transmissions to triangulate her position. The crew could receive broadcasts, and Schneider had the latitude to report serious circumstances if he felt it was warranted, but things like routinely reporting her position and administrative message traffic was not allowed.<br><br>
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[[File:Dorado zig zag course.jpg|left|thumb|250px|<small>Example of a zig-zag course, intended to disrupt the aim of an attacking submarine.</small>]]
<div style="text-align: justify;"><span style="color:#00008B">Another element of Dorado's voyage was that she was following a "zig-zag" course. This was a tactic that was intended to make it difficult for an enemy submarine to properly aim its torpedoes. German submarines were known to be operating in both the Atlantic and Caribbean and the danger of being attacked by one of them as Dorado made her transit south was very real. The defensive tactic of constantly shifting your course to either side of the base course would hopefully foul an enemy submarine's fire control solution, leading to misses. It resulted in it taking longer for Dorado to make her voyage, but this was all figured into her MOVORD timing.<br><br><br><br><br><br><br><br><br><br><br>
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[[File:Dorado submarine sanctuary zone 2.jpg|left|thumb|400px|<small>Graphic ©Thaddeus Weaver, 2025</small>]]
<div style="text-align: justify;"><span style="color:#00008B">The final element of Dorado's voyage south to Panama was the imposition of a Submarine Sanctuary Zone around the submarine. As the graphic shows, this was a moving zone centered on the submarine's "point of intended movement" or PIM. The PIM at any given time was dictated by the the position that Dorado should be at given her SOA. Dorado's track, her SOA, and the dimensions of this moving sanctuary zone were transmitted to all Allied commands in the Atlantic and Caribbean. The purpose of which was to prevent a blue-on-blue, or friendly fire incident from happening. Under no circumstances were any attacks to be made on suspected submarines within this zone, unless the ID of the submarine could be absolutely confirmed.
The zone was big enough to allow the zig-zag course to be conducted, and for periodic dives for training and drills. However, it was incumbent upon the crew of Dorado to ensure they stayed within the zone at all times. Allied surface and aerial forces were understandably a bit on edge due to the threat of German submarines, and this zone was intended to eliminate the "friendly" threat to U.S. submarines transiting to Panama.<br><br>
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===Prelude: October 11 and 12, 1943===
<div style="text-align: justify;"><span style="color:#00008B">The trip south through the Atlantic had not been a leisurely pleasure cruise. Schneider used the opportunity to constantly drill the crew and hone their skills. Drills of all sorts were run, ranging from fire and flooding to mock torpedo attacks. He would "crash dive" the boat at random intervals, a stop watch in his hand to evaluate how long it took to get the boat from fully surfaced to periscope depth (60 feet). A well trained crew could dive the big fleet boat in 35-40 seconds.
Around mid-day on October 11, the boat was approaching Point Dog, and they raised Cape Engano on the eastern tip of the island of Hispaniola right on time. They proceeded apace through the Mona Passage between the Dominican Republic and Puerto Rico, passing through Point Easy and out into the Caribbean. Dorado's base course between Points Easy and Fox was 243° true, or southwesterly, with the zig-zag plan having Dorado jinking left and right of that course.
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[[File:Dorado and GAT 92 12 Oct 43 ver 3.jpg|left|thumb|400px|<small>Graphic ©Thaddeus Weaver, 2025</small>]]
<div style="text-align: justify;"><span style="color:#00008B">By the late afternoon on October 12, Dorado had company on her transit across the Caribbean Sea. Allied convoy GAT 92 was enroute from Guantanamo Bay, Cuba to Trinidad with nine ships and was in the central Caribbean north of Dorado's position. The convoy originally consisted of 32 ships when it first departed New York, but some ships stayed in Guantanamo. Escorted by two Dutch and three U.S. patrol craft, the convoy was on a southeasterly course of 143° true. They were set to cross Dorado's path some time that night. The convoy commander had been fully briefed on Dorado's transit, and likewise Schneider and his crew knew of the convoy and their intentions. In addition to the five surface craft, the convoy fell under the protective umbrella of U.S. Navy patrol squadron VP-210 based at Guantanamo. The squadron consisted of 12 [[Dorado Martin PBM Mariner aircraft|'''Martin PBM-3S Mariner''']] flying boat patrol aircraft. On the evening of October 12th, one of these Mariners was flying cover over the convoy. This aircraft carried the call sign 210-P-9.<br><br><br><br><br>
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[[File:Dorado and position with GAT 92.jpg|left|thumb|400px|<small>Graphic ©Thaddeus Weaver, 2025</small>]]
<div style="text-align: justify;"><span style="color:#00008B">Unbeknownst to the convoy commander or the crew of Dorado, the crew of 210-P-9 had been incorrectly briefed on Dorado's actual position, based on an incorrect plotting of Dorado's course on the surface ship plotting board at the Joint Operations Center, Naval Operating Base, Guantanamo, Cuba. Because of this LT(jg) Daniel T. Felix, Jr., the aircraft commander and left seat pilot, and his crew believed that Dorado's base course was 31 NM miles to the south of where she actually was. 210-P-9 took off at dutifully at 3:40 pm and by that evening was patrolling out ahead of the convoy. They made radar contact on a surface target at 8:39 pm on October 12, and Felix and the crew made the justifiable assumption that it was an enemy U-boat because ''it was in an area where no U.S. submarine was supposed to be'', or so they believed.<br><br><br><br><br><br><br><br><br>
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===The critical 13 minutes: 8:39-8:52 pm, October 12, 1943===
<div style="text-align: justify;"><span style="color:#00008B">'''Author's note''': in this section, any text in ''italics'' will be speculation and conjecture based on first hand knowledge of submarine operations and established WWII USN submarine tactical procedures. Our intention is to provide some context as to what we believe was happening onboard Dorado during these critical 13 minutes. Since no one survived the sinking of Dorado there is no way to confirm the events that took place onboard, but we believe the actions as outlined are possible and realistic. The remainder of the text is fact based, taken from official U.S. Navy sources.<br><br>
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Upon detection of the surface target on radar, Felix continued to fly the PBM on its southerly course of 190° true. His intention was to visually acquire the target in order to make an evaluation. Sure enough, at eight nautical miles out the faint silhouette of a small ship was seen with binoculars in the bright moonlight. Felix immediately made a turn to the right. The intention was to swing around and place the target "up moon", that is silhouetted with the moon in the background. That would give his crew the maximum visibility of the target while at the same time hiding their approach in the black background.
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[[File:Dorado aircraft attack.jpg|left|thumb|400px|<small>Graphic ©Thaddeus Weaver, 2025</small>]]
<br><div style="text-align: justify;"><span style="color:#00008B">''Schneider was lying in his bunk in his small stateroom in the forward battery compartment and was casually leafing through a novel when the phone next to him buzzed. It was the Officer of the Deck on the bridge. "Captain, OOD. The previously detected aircraft now has a decreasing range, 10 miles and closing steadily." Schneider replied, "Very well. I'm on my way up." Schneider quickly put on his shoes and headed aft to the control room. He clambered up the ladder to the conning tower and went to the radar station on the starboard side. There he peered over the shoulder of the Radioman who was manning the station. The small circular A-scope screen of the SD air search radar showed the blip and its decreasing range. The SD set was a range only radar and did not provide a bearing. However it could safely be surmised that it was north of their position as that is the direction of the convoy. He wasn't overly concerned at this point, as he knew that it was an American aircraft protecting the convoy (the Germans obviously were not operating aircraft in the Caribbean), and he knew that Dorado was well within the sanctuary zone where no attacks were allowed.''
''He moved to his left and glanced at the gyrocompass repeater in front of the helmsman and saw that they were steady on course 310° true. The OOD was dutifully following the zig-zag plan and they were now to the right of their base course of 243° and temporarily headed northwest. He turned to the right and grabbed the rungs of the ladder to the bridge. Squeezing up through the open hatch, he was greeted by the Officer of the Deck announcing, "Captain on the bridge."''<br>
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Lieutenant Felix came out of the wide sweeping left turn and steadied up on course 090°, or due east and steadied at an altitude of 1000 feet. At 8:49 at a range of three nautical miles, both pilots and another crewman stationed at the nose gun station were able to confirm that the target was indeed a submarine. The sighting was fleeting, just a few seconds. Felix faced a dilemma, should he attack or try to confirm identity? Quickly mulling it over he realized that everything he had been briefed on, everything that he had trained for, and all of the information that the had told him that this was a German U-boat. He made the decision to attack. He begins a slow descent to release altitude at a speed of 170 knots.
''Fortunately, Schneider's eyes were already adapted to the dark. He had been wearing red lens goggles while resting in his cabin, and red lights were on in the forward battery and control room compartments, preventing night blindness. About four minutes had elapsed since he had arrived on the bridge, and he was diligently scanning the skies with binoculars, along with the two lookouts, the Officer of the Deck, and one Quartermaster. A call came up from the conning tower, "Bridge, radar. Aircraft contact now intermittent. Last good range 8000 yards". To Schneider this meant that the inbound aircraft was descending to the minimum altitude that the SD radar could track it, 1000 feet. Two seconds later, "Bridge, radar. Aircraft contact lost." Suddenly, the port lookout calls out, "Aircraft contact, three points on the port bow." Schneider swings around to the left, raises his binoculars, and peers intently into the blackness. A few seconds later he catches a faint moving shadow, close to the horizon, and the dim flashes of engine exhaust from two engines. He immediately thought "Looks like a PBM". Despite knowing this was a friendly aircraft, he was immediately wary. "Don't like the look of this", he thought.''
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[[File:Dorado PBM bombing attack.jpg|left|400px|<small>Graphic ©Thaddeus Weaver, 2025</small>]]
<div style="text-align: justify;"><span style="color:#00008B">Felix made a nearly perfect attack run. At 8:51 he released three [https://www.bulletpicker.com/bomb_-350-lb-depth_-an-mk-41_-.html '''Mk 47 depth charges'''] and one Mk 4 Mod 4 100 lb general purpose bomb from the two bomb bays in the engine nacelles behind each engine. As you can see from the Court of Inquiry graphic on the left, the bomb and the third depth charge most likely did not detonate, as the plane was too low for the bomb to arm, and there were problems found with the arming mechanism for the third depth charge when the plane returned to base. It should be emphasized that this pattern is an estimate only. NONE of the crew actually witnessed the impact of the weapons and they were too far away to have heard any explosions. It is likely that there was a little left\right separation of the ordnance, as two of them dropped from the left bomb bay and two from the right. However, if this graphic is at least close to reality, then the impact of the dud bomb and the detonation of the two other depth charges had the potential to cause serious damage to Dorado.
''Time had slowed for Schneider, and he stared at the approaching shape for what seemed like minutes, but was actually just three seconds. "Nope," he thought, "Don't like this at all." He pushed past the OOD and reached for the diving alarm switch. Turning slightly to his left he bellowed "Clear the Bridge" and pulled the diving alarm switch twice. The "aaoogahs" of the diving alarm jolted everyone awake below and initiated the maneuver that they had practiced repeatedly. Schneider's call of "Dive, dive" over the 1MC general announcing circuit backed up the urgency and instantly main ballast tanks vents were opened, engines were shut down, intake and exhaust valves shut, and the bow planes were rigged out. Schneider counted men as they jumped down the hatch, waiting until he was satisfied that all on the bridge were below. As he half fell, half climbed down the ladder himself he grabbed the hatch lanyard and pulled the hatch shut behind him, with the Quartermaster reaching up and dogging the hatch down tight. He yelled down the hatch to the control room, "Diving Officer, make your depth 200 feet smartly". He then ordered, "Helm all ahead flank". Back aft in the maneuvering room the electricians on watch positioned large switch levers to line up the two batteries in series, greatly increasing their voltage output, and they cranked the speed rheostats for the motors against their stops. Schneider felt the satisfying downward tilt of the deck and quietly muttered, "This is going to be close..."''
''No sooner had the words come out of his mouth when a loud WHANG preceded a jump in the deck, and the whole boat rattled. The 100 lb bomb had struck the aft part of the conning tower fairwater and although it did not detonate, it had enough kinetic energy to wreck the man-sized main air induction and main ventilation valves enclosed there. One second later the boat was pummeled by the nearly simultaneous detonations of two of the depth charges. Men were thrown to the deck, the lights went out, and the crew struggled to regain control as they nosed downward.''
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[[File:Dorado post bombing scene.jpg|left|thumb|400px|<small>Graphic ©Thaddeus Weaver, 2025</small>]]<div style="text-align: justify;"><span style="color:#00008B">As soon as the ordnance was away, Felix threw 210-P-9 into a hard left turn. His intent was to circle back and conduct a re-attack if necessary. One minute later, at 8:52, they arrived over the attack datum point and dropped a yellow flare. All that was revealed in the flickering light of the flare and the glare of the moon was a large patch of white, disturbed water and bubbles. No wreckage and no oil slick was observed. Admittedly, this is the exact scene that would have been observed if the boat had merely dived under its own power, but without any confirmatory evidence Felix and his crew were confident that they had at dealt the "U-boat" a heavy blow. They reported the incident via radio and continued on patrol, wary and on guard.
What happened to the Dorado at this point is very difficult to ascertain. Any number of circumstances could have befallen the boat, but the lack of wreckage and an oil slick on the surface means that at least she departed the surface intact. Predicated on the FACT that Dorado never made her rendezvous at Point George on the afternoon of October 14, some of the post-bombing scenarios may include:<br>
* Dorado was not damaged at all. Schneider makes a hard left turn to clear the attack datum point while simultaneously speeding up and getting the boat down to a safe depth. She then sinks later due to an unrelated equipment casualty.
* Dorado suffered some equipment derangement, possibly including a loss of electrical power, possibly including a "jam-dive" on the stern diving planes, etc. The crew loses control of the boat and she sinks below crush depth.
* A combination of the two above. Dorado suffered some damage, i.e. flooded engine induction piping, jam-dive on the stern planes, etc., but was able to fight the damage and keep the boat going for perhaps up to a half-hour or more, before succumbing to the circumstances and sinking.
Ultimately, it will require that the wreck be found and surveyed before many of these questions can be answered.
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===Further actions, 8:52-10:45 pm, October 12, 1943===
<div style="text-align: justify;"><span style="color:#00008B">'''Author's note:''' Post-war examination of the logs of German submarine U-214 revealed a discrepancy in recorded times of the following events. This discrepancy was up to 6 minutes and is likely due to the clocks of U-214 not being in perfect synchronization with those of the USN units, a common occurrence in the days prior to electronic navigation systems. When the observed events are examined together and compared they are close enough to determine that they are the same event.<br><br>
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German submarine U-214 was on her way home after a successful minelaying operation off the mouth of the Panama Canal. In the late evening of October 12, she was in the central Caribbean on a northeast course of 074°T enroute to Germany at a speed of about nine knots. At 7:35 pm she dropped over the side a single type EMS 1 floating mine and continued on her course without incident. At 8:57 far off in the distance at 050°T she spotted a yellow flare. This was the flare dropped by 210-P-9 during its attack run. The crew dutifully noted the incident in their log and U-214 continued on her way.
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[[File:Dorado DPL message.jpg|left|thumb|300px|Transcription of the "Details Plain Language" message.]]<div style="text-align: justify;"><span style="color:#00008B">At 9:50 pm, realizing that a plotting error had been made on their tracking board, the Joint Operations Center at Guantanamo sent out the following message and it was copied by the crew of 210-P-9: DETAILS PLAIN LANGUAGE FRIENDLY SUB IN AREA. LT(jg) Felix and his crew, now extra cautious, continued their aerial patrol ahead of convoy GAT 92.
At 10:33 pm they once again picked up a surface contact on their radar and closed to investigate. At 10:40 another submarine was sighted in the same general vicinity as the first one. Felix put his aircraft into a slow circle around the new contact and initiated a series of recognition signals via an Aldis signalling lamp. The response was the submarine opening fire with anti-aircraft guns on Felix's plane, and the pilot immediately began evasive maneuvers. 210-P-9 was not damaged and Felix turned the plane to attack. By this time the submarine vanished into a rain squall, diving to avoid further contact. 210-P-9 could not reestablish contact and so continued on its patrol, with no further incidents that night. Exact identification was not possible at the time, but since the submarine fired upon the aircraft it was assumed that it was an enemy U-boat. After the war the logs of U-214 were examined and the events recorded match that of 210-P-9, confirming that in the second attack that night the aircraft did indeed encounter U-214.
It should be noted that during the entire period of October 6-24, 1943 no radio messages of any kind were received at any station from Dorado.<br><br> 
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==The Aftermath and Final Conclusions==


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* October 14, 1943 - Dorado does not make her rendezvous at Point George. Several hours elapse as the local command waits to determine if she is simply late. With increasing dread as the day wears on, searches are launched by both air and sea. Over the next several days aircraft range up and down her projected track looking for oil slicks and wreckage. Two slicks are noted in the area of 210-P-9's attack and surface craft are sent to investigate. Samples of the slick are examined and determined to be non-petroleum based and organic in nature. No wreckage of any kind is ever found.


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* October 15, 1943 - The Commander, Caribbean Sea Frontier, Rear Admiral Arthur B. Cook, USN initiates a Board of Investigation (BOI), in order to examine the facts while they are still fresh in everyone's mind. The BOI had the legal authority to administer oaths to witnesses. The Senior Member of the board was Captain Harry D. McHenry, USN. It was conducted locally at Naval Operating Base Guantanamo Bay, Cuba.
 
* October 24, 1943 - With no hope remaining that the submarine might arrive in Coco Solo, the U.S. Navy reluctantly but officially declares the USS Dorado (SS-248) as overdue and presumed lost.
 
* October 26, 1943 - The BOI is concluded. The final opinions reached were that the sub described by 210-P-9’s crew imply a German U-boat was attacked, that both submarine sightings were likely the same U-boat, and that no damage was achieved by the attack by 210-P-9 due to the lack of evidence of oil or debris. Later reviews of the BOI give the appearance that the inquiry was rushed and incomplete, and while the facts that it documented are helpful, the conclusions reached seem unsubstantiated and murky.
 
* October 26, 1943 - On the same day that the BOI is concluded, under the authority of the Commander in Chief, U.S. Fleet and Chief of Naval Operations Admiral Ernest J. King, a formal Court of Inquiry (COI) is convened in Washington, DC. It carries the full weight of Navy Regulations and oversight at the highest levels of the Department of the Navy. The court is lead by respected submariner Admiral Thomas C. Hart, USN, who was called back to active duty from retirement to lead the court. Commander John L. Burnside, Jr., a submariner, is appointed as judge advocate. The inquiry lasts until November 20 and is as thorough and complete as was possible at that point in the war. In the end, it comes to some surprisingly different conclusions than the BOI. The COI report opines "That it is highly probable that USS DORADO was lost through the attack by plane No. 210-P-9." Although affirming that the "pilot was not in error in deciding to attack", they found that the crew of 210-P-9 was not properly trained in matters of German or U.S. submarine identification, or of submarine sanctuary zone doctrine such as the submarine's use of zig-zagging or freedom of range to operate within the zone.
 
* September 13, 1945 - After the conclusion of the war a thorough review of German records concerning this incident was possible and a memorandum was provided to Admiral King, the Chief of Naval Operations (CNO). U-214’s patrol log reported "a bright yellow light on the horizon" at the vicinity and time of 210-P-9’s depth charge attack (which was considered to be 210-P-9’s flare) and of opening fire two hours later on 210-P-9. No other U-boats were in the area at the time (within 800 nm). It concluded that 210-P-9’s ''first attack'' was "not on U-214 nor any other German U-Boat" and further stated that "USS DORADO was not sunk by German U-Boat".<br><br>
 
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===Bottom line===
 
<div style="text-align: justify;"><span style="color:#00008B">So, with everything that has been put forth on this page, we feel that it is helpful to summarize some pertinent facts and end with logic based conclusions.
* Only two nations were operating submarines in the Caribbean in October of 1943: the United States Navy and the Kriegsmarine of Germany.
* No other U.S. submarine was in the Caribbean on October 12, 1943, and the only German U-boat within 800 nautical miles of the scene was U-214.
* Based on the scope of her MOVORD, Dorado should have been in the central Caribbean on the night of October 12, 1943.
* Despite acknowledged deficiencies in training for the crew of 210-P-9 in submarine identification, and despite the brief glimpse of the target prior to the release of ordnance, there is an extremely high probability that they bombed, at the very minimum, a "submarine like object" at 8:51 pm on the night of October 12, 1943.
* The submarine like object bombed by 210-P-9 during the first attack that night WAS NOT U-214 or any other U-boat.
* Weather played no direct role in the loss of Dorado.
* It is highly unlikely, given the level of experience, training, and sea trial evaluations of Dorado that she was lost SOLELY to equipment malfunction or operational accident.
* Dorado was not lost by direct attack by a German U-boat.
* Dorado DID NOT strike one of the mines laid by U-214 near the entrance to the Panama Canal, and there is only a vanishingly small chance that she struck the lone type EMS 1 mine set adrift by U-214 on the evening of October 12.
* As far as can be determined, no radio messages of any type were received from Dorado at any station.
* Dorado never arrived for her rendezvous at Point George, and no relevant debris or confirmed oil/fuel slick was ever found.


'''Therefore''', the ''precipitating event'' in the loss of USS Dorado (SS-248) was the bombing by aircraft 210-P-9 at 8:51 pm on the night of October 12, 1943. Dorado likely sank in the vicinity of the attack.
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Executive Summary (aka "Bottom line up front")

The USS Dorado Project team believes that Dorado was lost due to a friendly fire incident in the central Caribbean on the night of October 12, 1943. Her wreck site and final resting place likely is in the vicinity of that attack. Our case is spelled out below.

Background: Loss scenarios, facts, & other data

Introduction

Until the wreck site of Dorado is found, no one, including the members of this team, can say definitively what actually happened to Dorado and her crew. The case that we will present below is based on meticulous research in official Navy documents, especially excerpts from the two official inquiries into her loss. It is as fact based as we can possibly make it at this time. In order to round out the narrative, there are times in which Thaddeus and the team have used informed speculation based on years of research and personal experience. Every effort has been made to keep speculation to a minimum. There are times in which the narrative gets rather vague, and that is because no verifiable information about those periods exist. The team used first hand personal experience in submarine operations to help fill in the gaps. An example would be the period of Dorado's transit south through the Atlantic.

Another important note: the authors made the conscious decision to use the 12 hour time and month/day/year date format familiar to the American public. Since the majority of our audience will be civilans, we shied away from using a military or European time/date format in order to prevent confusion. Thank you for your understanding in this matter.

Possible causes for Dorado's loss

In developing the loss scenario, the authors considered all possible and realistic causes for her loss. We distilled the causes down to five possibilities. Each of these potential causes were extensively studied by the team and given a probability ranking. Each will be explained in detail below.

Weather

The Gato-class submarines were very good sea boats, when compared to other submarines. They could handle heavy weather with relative ease on the surface, although it would still be a rough ride for the crew. An example is the USS Sailfish (SS-192). She was a Salmon/Sargo-class boat and slightly smaller than Dorado, but endured a typhoon off the southern coast of Japan while attacking a Japanese task force. Pushing through "mountainous" seas with zero visibility, Sailfish frequently took solid water over the bridge, but her crew pushed on and eventually sank an aircraft carrier. Sailfish and other submarines proved the sea worthiness of the fleet submarine design.

A meteorologist/aeroligist from the Office of the Chief of Naval Operations testified at the Court of Inquiry and stated that Dorado did not encounter any adverse weather during her entire transit from New London. The only disturbance of note was a tropical depression that originated in the vicinity of St. Lucia in the Lesser Antilles far to the east sometime on the 11th of October, moving slowly northwest. It would have passed over Puerto Rico and the Dominican Republic on the night of October 13-14, well after the Dorado would have passed through that area.

In fact, aircraft observations of the weather conditions in the central Caribbean on the night of October 12 stated that the sea was moderate, with visibility at eight miles and a wind of eight knots. It did state that there were "numerous squalls" in the area, but those rain showers would have not affected Dorado in any meaningful way.

It is the opinion of the authors that the weather conditions were will within the capability of Dorado to successfully navigate, and that the weather played no part in her loss.

Mechanical Failure or Operational Accident

Operating a submarine at sea, even in peacetime, is an exceedingly dangerous evolution. Operating under the surface of the ocean, in pressures of several hundred pounds per square inch, greatly complicates the otherwise well known process of taking a ship to sea. Since 1900, the United States Navy alone has suffered 14 peacetime accidents that resulted in the submarine sinking to the bottom. In WW II the USN lost 52 submarines, seven of which were due to non-enemy related accidents. In addition to these losses, there have been dozens of incidents in which lives were lost and the submarine damaged, but in which neither the boat nor significant portions crew were lost. It is distinctly possible that Dorado was lost as a result of one of these circumstances. Mechanical failure or operational accidents can take many forms, and we have listed some common (but obviously not all) scenarios below, along with an assessment of their probability.
  • Stern planes jam dive - The stern diving planes, fashioned like horizontal rudders and located aft of the propellers, are used to control the angle of the boat while it is submerged. A failure of the mechanical or hydraulic systems that control and operate the planes could lead them to become stuck in the full dive position, pushing the boat into a steep dive and rendering it uncontrollable. Example: Chopper (SS-342), 1969. Probability: very low. Dorado was a new boat and had been extensively tested and inspected prior to departure.
  • Valve failure - If a valve fails to operate or structurally fails under submergence pressure, rapid and possibly uncontrollable flooding can occur. Example: Squalus (SS-192), 1939. Probability: very low, for the same reasons listed above.
  • Battery explosion and fire - Dorado was equipped with two 126-cell lead acid storage batteries, used to provide electricity to electric motors for submerged propulsion. The batteries have to be periodically recharged using the diesel generator sets, and this process is tricky and dangerous if not closely monitored and regulated. When charging, the battery cells can generate extremely flammable hydrogen gas, which if it builds up to high levels can generate an explosion. Related to this is the fact that the batteries can also generate very lethal chlorine gas if sea water is allowed to get into the cells. Every once in a while, this process goes wrong, with disastrous results. Example: Cochino (SS-345), 1949. Probability: medium to low. This is a well practiced procedure that the crew is thoroughly trained for. Most submarines charge their batteries several times a day without incident.
  • Collision - A collision involving a submarine usually ends up in disaster for the sub. It will sink quickly due to its relatively low reserve buoyancy. Example: S-51 (SS-162) collision, 1925. Probability: very low. No reported collisions occurred anywhere along Dorado's route.
  • Hull structural failure - Sometimes a submarine's hull can structurally fail under submergence compression due to age, structural failure, or due to unknown damage. The results are usually catastrophic. Example: S-28 (SS-133). Probability: negligible. Dorado was a brand new boat and had been fully tested to its maximum rated depth.

Any of these scenarios is indeed a possible explanation for Dorado's loss, and they can't be definitively ruled out until the wreck is found and surveyed. However, the authors are confident that none of them are the precipitating event that caused her loss, for reasons put forth throughout this page.

Attack by a U-boat

German U-boats were a known threat off of the Atlantic coast of the U.S. in 1943. U.S. submarines transiting to Panama were on constant alert, and some boats were detailed to anti U-boat patrols along the route. USS Mackerel (SS-204) was actually fired upon by a U-boat off Virginia in April, 1942. She narrowly avoided the torpedoes and then counter-attacked with her own, but was not successful. Although German activity in the western Atlantic and Caribbean had peaked the previous year, U-boats were still operating in the area in the summer and fall of 1943.

Type VIID U-boat minelayer
At the time of Dorado's loss, two U-boats were in the general vicinity. U-518, a Type IXC long range boat, was operating in the Gulf of Mexico, 870 nautical miles to the northwest and can be ruled out as having played a part. U-214, a Type VIID minelaying boat was in the central Caribbean on her seventh war patrol. She was on a mission to lay mines near the entrance to the Panama Canal (see below) and in fact had already done so and was on her return leg to Germany. U-214 survived this patrol and successfully returned to Germany. After the war her log was examined. There was no entry describing a torpedo attack on a U.S. submarine, nor any entry describing even the sighting of a submarine.

For these and other reasons outlined here, a direct attack by an enemy submarine on the Dorado can be definitively ruled out as a cause of her loss.

Mine strike

The authors considered the possibility of Dorado striking a mine along her route. This has been a leading theory in the past regarding the loss of Dorado. German U-boats were known to undertake mine laying missions off the U.S. coast. Mine fields can only be laid in relatively shallow (2000 feet or less) waters near shore. There were no known minefields in the Long Island/Block Island Sound area at the beginning of the voyage; indeed there were no reports of mine detonations in that area in October. The deep water that made up the majority of Dorado's route to Panama was not conducive to mining. Therefore these areas can be ruled out.

German Type SMA mine.
However, as stated above, U-214 was on a mission to lay a mine field near the Caribbean entrance to the Panama Canal that October. The specialized mine layer was perfectly suited for the job, although she was at the limit of her range to do so. U-214 was equipped with five vertical mine tubes in a compartment immediately aft of the control room. These tubes were capable of holding three mines each, and U-214 carried a total of 15 Type SMA mines on this patrol, in addition to her normal complement of 14 torpedoes. The mines were laid dropping them out of the bottom of the tube, as shown in the illustration above. The process could be accomplished while the boat was submerged. In early October she laid these mines in an west to east slightly curved linear pattern, roughly eight nautical miles north of the Cristobal/Colon harbor breakwater. This area laid astride the very busy shipping lanes to and from the canal and was ideal to disrupt shipping patterns and sink ships. Dozens of ships, both civilian and military passed through this area daily. The SMA was a moored magnetic influence mine, meaning the disruption of the Earth's magnetic field as a steel-hulled ship passed near would trigger the detonator. It had a 772 lb (350 kg) explosive charge and was a deadly weapon.

Once dropped from the tube the weapon would sink to the bottom. A hydrostatic switch would then activate, releasing the upper explosive mine from its weighted base, with the mine floating up on its cable to a pre-set depth where it would activate. It was supposed to remain moored via the cable to its base until detonated by a passing ship. The mines would be laid one at a time, at the prescribed interval to achieve the desired field shape. The delay in activation was intentional, allowing the U-boat to open enough distance so that the mine would not detonate from the effects of the U-boat's hull.


Graphic ©Thaddeus Weaver, 2025
The graphic at right shows some key data points when considering the mine strike scenario. The points in red labeled 1 to 15 are the locations of each mine plant, taken directly from the U-214's log. As you can see the field was laid astride the shipping lane to the entrance to the canal, which is in Limon Bay just to the west of Colòn and Cristobal near the bottom of the chart. Any ships approaching or departing the canal would have to pass through the minefield.

The points in black labeled A through J are the reported locations of the mines when they were detected and swept by U.S. forces. The data in the lower left gives the dates when the mines were found. The discrepancies in location are to be expected. U-214's plotting of the field was likely not as precise as they recorded it due to the limitations of navigation in that period (no GPS or precise electronic navigation systems). The same can be said for the recorded U.S. locations. It should also be noted that mine "A" (U.S.) does not necessarily correspond to mine "1" (German), etc.

There are several other very important data points on this chart. First, the first mine was discovered and swept by U.S. forces on October 9, Just three days after Dorado's departure from New London and while she was still well out in the Atlantic on her transit (see below). The presence of the mine field was already known prior to Dorado's scheduled arrival and it was actively being swept and neutralized.

Second, the prevailing currents in the area were to the east-northeast. Any mines that broke free of their mooring cables or had their cables cut by the minesweepers would have drifted on the currents in that direction, well out of the path that Dorado was following to Point George. Indeed, mine "I", swept on October 29 but not immediately destroyed, drifted northeast past Manzillo Point before it was finally neutralized.

Third, and most importantly, Point George, Dorado's final navigation waypoint and the spot she was to rendezvous with the USN destroyer on the surface, was seven nautical miles north of the northern most boundary of the minefield. Dorado could not possibly have contacted one of U-214's mines as they were all laid to the south of the rendezvous position. After that point she was to proceed on the surface under escort of the destroyer and the two ships would have transited through an already swept lane to the submarine base at Coco Solo. Other than the detonations of the mines by the minesweepers as they were being neutralized, no underwater explosions were reported by any of the numerous ships in the area, which would have been an indication that a submarine had contacted a mine.


German type EMS 1 mine.
There is one other mine theory to be considered. U-214 also carried four small type EMS 1 floating mines. These small mines were designed to be deployed over the side by hand by a crewman on the aft deck while the boat was on the surface. They had a small 24 to 30 lb. explosive charge and were intended to be deployed in a shipping lane where a ship could contact one by running into it.

At 7:35 pm on the evening of October 12, 1943 the U-214 deployed one of these mines in a position southwest of Dorado, and unknowingly, generally in the path Dorado needed to take to get to Point George. The datum point for this deployment was roughly 40 nautical miles south-southwest from Dorado's position at the time, and to the left of her plotted track. The prevailing currents in the area would have the EMS mine drift on a divergent course east-northeast and out of the Dorado's way.

Assuming that Dorado made it that far, the chances of her running into this small, singular floating mine in the vastness of the central Caribbean is infinitesimal at best. While this remains a viable theory, we rate its probability as negligible to zero.






In summary, there is ZERO chance that Dorado struck one of the mines laid by U-214 in early October off the entrance to the canal, and a NEGLIGIBLE chance that she struck the lone floating type EMS 1 mine deployed by U-214 on the evening of October 12, 1943. Dorado's loss to a mine strike is therefore highly improbable.

Friendly fire

World War II was warfare on a nearly unimaginable scale, fought by well equipped and highly motivated forces. The sheer scope of the conflict, combined with the enormous number of combatants, makes it inevitable that the "fog of war" will eventually creep in, dangerously confusing the battlefield. That fog of war resulted in numerous "friendly fire" incidents, in which forces mistakenly fired upon their own side, thinking they were the enemy.

In the U.S. Submarine Service there is precedent for this. Several incidents occurred throughout the war. The famous Harder (SS-257) was attacked by friendly aircraft in the Caribbean on May 2, 1943. She escaped without damage and immediately reported the incident. Seawolf (SS-197) was lost on October 3, 1944 after being mistakenly attacked by the USS Richard M. Rowell (DE-403) off Morotai island in the Pacific.

An incident occurred on the night of October 12, 1943 in the central Caribbean in which a USN PBM-3S Mariner patrol aircraft bombed a surfaced submarine. Based on her orders, Dorado was likely in the area at the time of this incident. The authors believe that this is the precipitating event that lead to the Dorado's loss. Our scenario explaining this theory is laid out in detail below.

The Loss Scenario

What we present below is the scenario as we believe it to be at this time, and it admittedly is not the only possibility. Subsequent research and/or actually finding the wreck site has the potential to radically alter the story. Thank you for your interest. If you have questions or comments, please direct them to ussdoradoproject@gmail.com.

The Departure

USS Flasher (SS-249), Dorado's sister boat, on sea trials in 1943. Dorado would have been configured very close to this when she left for war. NARA photo #80-G-450241 via Navsource.net.
On the morning of October 6, 1943, Dorado backed smartly out of her slip at Submarine Base New London, Groton, CT., put on some left rudder, and swung her stern to the north and up river. Expertly timing the swing, LCDR Schneider, present on the bridge with several other crewmen, ordered zero rudder and all stop. He then ordered "all ahead two thirds" and Dorado began her trip down the Thames River, headed to Long Island Sound and eventually the Atlantic Ocean.

She passed under the U.S. Route 1 bridge, with the venerable structure lifted open to allow the boat to pass underneath. She passed the main Electric Boat facility on her port beam, and a little further downstream she passed the Victory Yard where she was built. Men and women toiling in the cool October air on Dorado's sister subs paused for a moment, proudly acknowledging their handiwork as the submarine passed. They wished her luck as she headed off to war.

The crew was experiencing a mixed set of emotions. They had come to enjoy their stay in Connecticut and had a deep appreciation for the hard work put forth on their behalf by the Electric Boat personnel. Friendships had developed with the workers that the men valued. Some of the crew had brought family members to the Groton/New London area and they were now leaving that all behind; a touch of sadness prevailed as they sailed down the Thames River. There was also a palpable sense of anxiety as they pushed the bow of the boat into the unknown. The experienced men knew of the combat that laid ahead, the inexperienced men put on a brave face as they tamped down their fears. All of that was tempered by the excitement of finally moving forward. They were well trained and confident in themselves and their shipmates, and despite lingering anxiety they eagerly anticipated the adventure that laid ahead.

Fishing vessels hailed her as she passed the mouth of the Thames and Schneider rang up an ahead standard bell with turns for 14 knots. The bridge watch team kept a wary eye on the Fisher's Island and Montauk ferries as they passed, with a little maneuvering left and right intended to keep the ferries at a safe distance. Clearing Fisher's Island she made a slight turn to the southeast, putting her on course to pass down the middle between Montauk Point on her starboard side and Block Island on her port. Down below in the conning tower and control room the Quartermasters and the Navigator were busy piloting the submarine, shooting bearings with the periscope to land-based navigation aids, using those bearings to triangulate their position on the chart. With Montauk Point on their starboard quarter, they took their "point of departure", i.e. the last confirmed land-based navigational fix, and headed out into the blue Atlantic.

The Voyage

Graphic ©Thaddeus Weaver, 2025
Dorado's voyage orders were referred to by the Navy as a Movement Order, or MOVORD. Dorado's MOVORD for the initial leg contained seven waypoints, Able to George. They would route her out into the Atlantic and south towards the Caribbean. Her destination was Submarine Base Coco Solo, on the Atlantic side of the Panama Canal near the city of Colon. She would briefly stop there to refuel and reprovision prior to her transit through the Panama Canal and the second leg out across the Pacific to Hawaii.

The final waypoint was Point George, 15 nautical miles (NM) north of the Cristobal Breakwater, a structure that defined the harbor for Cristobal and Colon. At George the Dorado was to rendezvous with a U.S. destroyer, who would escort Dorado on the surface the last few miles to the submarine base. This rendezvous was supposed to happen at 11:00 local on the morning of October 14. This date/time is very important for several reasons:

  • Being escorted into the harbor by the destroyer would prevent Dorado from being mistaken for a German submarine (known to be operating in the Caribbean) and being fired upon by friendly forces. Being early or late for the rendezvous was frowned upon, as it would cause serious tactical, operational, and logistical problems that the Navy wanted to avoid.

  • Traffic through the canal was very high, and specific times were assigned to ships for passage so that the possibility of traffic jams was avoided. If Dorado missed her transit time, it would delay her voyage all the way to Pearl Harbor and the war zone and exacerbate the operational and logistical issues previously mentioned.

  • The date/time of her arrival at Point George also dictated the speed of her transit, known properly as her "speed of advance" (SOA). To make Point George on time her SOA was 14 knots. This was also a fuel efficient speed and was well within her maximum surface speed of 21 knots. However, it also dictated that Dorado make the transit mostly on the surface, as her maximum submerged speed was only eight knots. LCDR Schneider had the discretion to submerge as he saw fit for drills and training, but he had to maintain the average speed of 14 knots in order to make George on time.

Dorado would also make the voyage under a condition known as "radio silence". This was a procedure in which Dorado was not to use her radio for routine transmissions, out of a concern that German submarines in the area might use those transmissions to triangulate her position. The crew could receive broadcasts, and Schneider had the latitude to report serious circumstances if he felt it was warranted, but things like routinely reporting her position and administrative message traffic was not allowed.


Example of a zig-zag course, intended to disrupt the aim of an attacking submarine.
Another element of Dorado's voyage was that she was following a "zig-zag" course. This was a tactic that was intended to make it difficult for an enemy submarine to properly aim its torpedoes. German submarines were known to be operating in both the Atlantic and Caribbean and the danger of being attacked by one of them as Dorado made her transit south was very real. The defensive tactic of constantly shifting your course to either side of the base course would hopefully foul an enemy submarine's fire control solution, leading to misses. It resulted in it taking longer for Dorado to make her voyage, but this was all figured into her MOVORD timing.











Graphic ©Thaddeus Weaver, 2025
The final element of Dorado's voyage south to Panama was the imposition of a Submarine Sanctuary Zone around the submarine. As the graphic shows, this was a moving zone centered on the submarine's "point of intended movement" or PIM. The PIM at any given time was dictated by the the position that Dorado should be at given her SOA. Dorado's track, her SOA, and the dimensions of this moving sanctuary zone were transmitted to all Allied commands in the Atlantic and Caribbean. The purpose of which was to prevent a blue-on-blue, or friendly fire incident from happening. Under no circumstances were any attacks to be made on suspected submarines within this zone, unless the ID of the submarine could be absolutely confirmed.

The zone was big enough to allow the zig-zag course to be conducted, and for periodic dives for training and drills. However, it was incumbent upon the crew of Dorado to ensure they stayed within the zone at all times. Allied surface and aerial forces were understandably a bit on edge due to the threat of German submarines, and this zone was intended to eliminate the "friendly" threat to U.S. submarines transiting to Panama.

Prelude: October 11 and 12, 1943

The trip south through the Atlantic had not been a leisurely pleasure cruise. Schneider used the opportunity to constantly drill the crew and hone their skills. Drills of all sorts were run, ranging from fire and flooding to mock torpedo attacks. He would "crash dive" the boat at random intervals, a stop watch in his hand to evaluate how long it took to get the boat from fully surfaced to periscope depth (60 feet). A well trained crew could dive the big fleet boat in 35-40 seconds.

Around mid-day on October 11, the boat was approaching Point Dog, and they raised Cape Engano on the eastern tip of the island of Hispaniola right on time. They proceeded apace through the Mona Passage between the Dominican Republic and Puerto Rico, passing through Point Easy and out into the Caribbean. Dorado's base course between Points Easy and Fox was 243° true, or southwesterly, with the zig-zag plan having Dorado jinking left and right of that course.

Graphic ©Thaddeus Weaver, 2025
By the late afternoon on October 12, Dorado had company on her transit across the Caribbean Sea. Allied convoy GAT 92 was enroute from Guantanamo Bay, Cuba to Trinidad with nine ships and was in the central Caribbean north of Dorado's position. The convoy originally consisted of 32 ships when it first departed New York, but some ships stayed in Guantanamo. Escorted by two Dutch and three U.S. patrol craft, the convoy was on a southeasterly course of 143° true. They were set to cross Dorado's path some time that night. The convoy commander had been fully briefed on Dorado's transit, and likewise Schneider and his crew knew of the convoy and their intentions. In addition to the five surface craft, the convoy fell under the protective umbrella of U.S. Navy patrol squadron VP-210 based at Guantanamo. The squadron consisted of 12 Martin PBM-3S Mariner flying boat patrol aircraft. On the evening of October 12th, one of these Mariners was flying cover over the convoy. This aircraft carried the call sign 210-P-9.





Graphic ©Thaddeus Weaver, 2025
Unbeknownst to the convoy commander or the crew of Dorado, the crew of 210-P-9 had been incorrectly briefed on Dorado's actual position, based on an incorrect plotting of Dorado's course on the surface ship plotting board at the Joint Operations Center, Naval Operating Base, Guantanamo, Cuba. Because of this LT(jg) Daniel T. Felix, Jr., the aircraft commander and left seat pilot, and his crew believed that Dorado's base course was 31 NM miles to the south of where she actually was. 210-P-9 took off at dutifully at 3:40 pm and by that evening was patrolling out ahead of the convoy. They made radar contact on a surface target at 8:39 pm on October 12, and Felix and the crew made the justifiable assumption that it was an enemy U-boat because it was in an area where no U.S. submarine was supposed to be, or so they believed.








The critical 13 minutes: 8:39-8:52 pm, October 12, 1943

Author's note: in this section, any text in italics will be speculation and conjecture based on first hand knowledge of submarine operations and established WWII USN submarine tactical procedures. Our intention is to provide some context as to what we believe was happening onboard Dorado during these critical 13 minutes. Since no one survived the sinking of Dorado there is no way to confirm the events that took place onboard, but we believe the actions as outlined are possible and realistic. The remainder of the text is fact based, taken from official U.S. Navy sources.

Upon detection of the surface target on radar, Felix continued to fly the PBM on its southerly course of 190° true. His intention was to visually acquire the target in order to make an evaluation. Sure enough, at eight nautical miles out the faint silhouette of a small ship was seen with binoculars in the bright moonlight. Felix immediately made a turn to the right. The intention was to swing around and place the target "up moon", that is silhouetted with the moon in the background. That would give his crew the maximum visibility of the target while at the same time hiding their approach in the black background.

Graphic ©Thaddeus Weaver, 2025

Schneider was lying in his bunk in his small stateroom in the forward battery compartment and was casually leafing through a novel when the phone next to him buzzed. It was the Officer of the Deck on the bridge. "Captain, OOD. The previously detected aircraft now has a decreasing range, 10 miles and closing steadily." Schneider replied, "Very well. I'm on my way up." Schneider quickly put on his shoes and headed aft to the control room. He clambered up the ladder to the conning tower and went to the radar station on the starboard side. There he peered over the shoulder of the Radioman who was manning the station. The small circular A-scope screen of the SD air search radar showed the blip and its decreasing range. The SD set was a range only radar and did not provide a bearing. However it could safely be surmised that it was north of their position as that is the direction of the convoy. He wasn't overly concerned at this point, as he knew that it was an American aircraft protecting the convoy (the Germans obviously were not operating aircraft in the Caribbean), and he knew that Dorado was well within the sanctuary zone where no attacks were allowed.

He moved to his left and glanced at the gyrocompass repeater in front of the helmsman and saw that they were steady on course 310° true. The OOD was dutifully following the zig-zag plan and they were now to the right of their base course of 243° and temporarily headed northwest. He turned to the right and grabbed the rungs of the ladder to the bridge. Squeezing up through the open hatch, he was greeted by the Officer of the Deck announcing, "Captain on the bridge."

Lieutenant Felix came out of the wide sweeping left turn and steadied up on course 090°, or due east and steadied at an altitude of 1000 feet. At 8:49 at a range of three nautical miles, both pilots and another crewman stationed at the nose gun station were able to confirm that the target was indeed a submarine. The sighting was fleeting, just a few seconds. Felix faced a dilemma, should he attack or try to confirm identity? Quickly mulling it over he realized that everything he had been briefed on, everything that he had trained for, and all of the information that the had told him that this was a German U-boat. He made the decision to attack. He begins a slow descent to release altitude at a speed of 170 knots.

Fortunately, Schneider's eyes were already adapted to the dark. He had been wearing red lens goggles while resting in his cabin, and red lights were on in the forward battery and control room compartments, preventing night blindness. About four minutes had elapsed since he had arrived on the bridge, and he was diligently scanning the skies with binoculars, along with the two lookouts, the Officer of the Deck, and one Quartermaster. A call came up from the conning tower, "Bridge, radar. Aircraft contact now intermittent. Last good range 8000 yards". To Schneider this meant that the inbound aircraft was descending to the minimum altitude that the SD radar could track it, 1000 feet. Two seconds later, "Bridge, radar. Aircraft contact lost." Suddenly, the port lookout calls out, "Aircraft contact, three points on the port bow." Schneider swings around to the left, raises his binoculars, and peers intently into the blackness. A few seconds later he catches a faint moving shadow, close to the horizon, and the dim flashes of engine exhaust from two engines. He immediately thought "Looks like a PBM". Despite knowing this was a friendly aircraft, he was immediately wary. "Don't like the look of this", he thought.

Graphic ©Thaddeus Weaver, 2025
Graphic ©Thaddeus Weaver, 2025
Felix made a nearly perfect attack run. At 8:51 he released three Mk 47 depth charges and one Mk 4 Mod 4 100 lb general purpose bomb from the two bomb bays in the engine nacelles behind each engine. As you can see from the Court of Inquiry graphic on the left, the bomb and the third depth charge most likely did not detonate, as the plane was too low for the bomb to arm, and there were problems found with the arming mechanism for the third depth charge when the plane returned to base. It should be emphasized that this pattern is an estimate only. NONE of the crew actually witnessed the impact of the weapons and they were too far away to have heard any explosions. It is likely that there was a little left\right separation of the ordnance, as two of them dropped from the left bomb bay and two from the right. However, if this graphic is at least close to reality, then the impact of the dud bomb and the detonation of the two other depth charges had the potential to cause serious damage to Dorado.

Time had slowed for Schneider, and he stared at the approaching shape for what seemed like minutes, but was actually just three seconds. "Nope," he thought, "Don't like this at all." He pushed past the OOD and reached for the diving alarm switch. Turning slightly to his left he bellowed "Clear the Bridge" and pulled the diving alarm switch twice. The "aaoogahs" of the diving alarm jolted everyone awake below and initiated the maneuver that they had practiced repeatedly. Schneider's call of "Dive, dive" over the 1MC general announcing circuit backed up the urgency and instantly main ballast tanks vents were opened, engines were shut down, intake and exhaust valves shut, and the bow planes were rigged out. Schneider counted men as they jumped down the hatch, waiting until he was satisfied that all on the bridge were below. As he half fell, half climbed down the ladder himself he grabbed the hatch lanyard and pulled the hatch shut behind him, with the Quartermaster reaching up and dogging the hatch down tight. He yelled down the hatch to the control room, "Diving Officer, make your depth 200 feet smartly". He then ordered, "Helm all ahead flank". Back aft in the maneuvering room the electricians on watch positioned large switch levers to line up the two batteries in series, greatly increasing their voltage output, and they cranked the speed rheostats for the motors against their stops. Schneider felt the satisfying downward tilt of the deck and quietly muttered, "This is going to be close..."

No sooner had the words come out of his mouth when a loud WHANG preceded a jump in the deck, and the whole boat rattled. The 100 lb bomb had struck the aft part of the conning tower fairwater and although it did not detonate, it had enough kinetic energy to wreck the man-sized main air induction and main ventilation valves enclosed there. One second later the boat was pummeled by the nearly simultaneous detonations of two of the depth charges. Men were thrown to the deck, the lights went out, and the crew struggled to regain control as they nosed downward.

Graphic ©Thaddeus Weaver, 2025
As soon as the ordnance was away, Felix threw 210-P-9 into a hard left turn. His intent was to circle back and conduct a re-attack if necessary. One minute later, at 8:52, they arrived over the attack datum point and dropped a yellow flare. All that was revealed in the flickering light of the flare and the glare of the moon was a large patch of white, disturbed water and bubbles. No wreckage and no oil slick was observed. Admittedly, this is the exact scene that would have been observed if the boat had merely dived under its own power, but without any confirmatory evidence Felix and his crew were confident that they had at dealt the "U-boat" a heavy blow. They reported the incident via radio and continued on patrol, wary and on guard.

What happened to the Dorado at this point is very difficult to ascertain. Any number of circumstances could have befallen the boat, but the lack of wreckage and an oil slick on the surface means that at least she departed the surface intact. Predicated on the FACT that Dorado never made her rendezvous at Point George on the afternoon of October 14, some of the post-bombing scenarios may include:

  • Dorado was not damaged at all. Schneider makes a hard left turn to clear the attack datum point while simultaneously speeding up and getting the boat down to a safe depth. She then sinks later due to an unrelated equipment casualty.
  • Dorado suffered some equipment derangement, possibly including a loss of electrical power, possibly including a "jam-dive" on the stern diving planes, etc. The crew loses control of the boat and she sinks below crush depth.
  • A combination of the two above. Dorado suffered some damage, i.e. flooded engine induction piping, jam-dive on the stern planes, etc., but was able to fight the damage and keep the boat going for perhaps up to a half-hour or more, before succumbing to the circumstances and sinking.

Ultimately, it will require that the wreck be found and surveyed before many of these questions can be answered.

Further actions, 8:52-10:45 pm, October 12, 1943

Author's note: Post-war examination of the logs of German submarine U-214 revealed a discrepancy in recorded times of the following events. This discrepancy was up to 6 minutes and is likely due to the clocks of U-214 not being in perfect synchronization with those of the USN units, a common occurrence in the days prior to electronic navigation systems. When the observed events are examined together and compared they are close enough to determine that they are the same event.

German submarine U-214 was on her way home after a successful minelaying operation off the mouth of the Panama Canal. In the late evening of October 12, she was in the central Caribbean on a northeast course of 074°T enroute to Germany at a speed of about nine knots. At 7:35 pm she dropped over the side a single type EMS 1 floating mine and continued on her course without incident. At 8:57 far off in the distance at 050°T she spotted a yellow flare. This was the flare dropped by 210-P-9 during its attack run. The crew dutifully noted the incident in their log and U-214 continued on her way.

Transcription of the "Details Plain Language" message.
At 9:50 pm, realizing that a plotting error had been made on their tracking board, the Joint Operations Center at Guantanamo sent out the following message and it was copied by the crew of 210-P-9: DETAILS PLAIN LANGUAGE FRIENDLY SUB IN AREA. LT(jg) Felix and his crew, now extra cautious, continued their aerial patrol ahead of convoy GAT 92.

At 10:33 pm they once again picked up a surface contact on their radar and closed to investigate. At 10:40 another submarine was sighted in the same general vicinity as the first one. Felix put his aircraft into a slow circle around the new contact and initiated a series of recognition signals via an Aldis signalling lamp. The response was the submarine opening fire with anti-aircraft guns on Felix's plane, and the pilot immediately began evasive maneuvers. 210-P-9 was not damaged and Felix turned the plane to attack. By this time the submarine vanished into a rain squall, diving to avoid further contact. 210-P-9 could not reestablish contact and so continued on its patrol, with no further incidents that night. Exact identification was not possible at the time, but since the submarine fired upon the aircraft it was assumed that it was an enemy U-boat. After the war the logs of U-214 were examined and the events recorded match that of 210-P-9, confirming that in the second attack that night the aircraft did indeed encounter U-214.

It should be noted that during the entire period of October 6-24, 1943 no radio messages of any kind were received at any station from Dorado.

The Aftermath and Final Conclusions

  • October 14, 1943 - Dorado does not make her rendezvous at Point George. Several hours elapse as the local command waits to determine if she is simply late. With increasing dread as the day wears on, searches are launched by both air and sea. Over the next several days aircraft range up and down her projected track looking for oil slicks and wreckage. Two slicks are noted in the area of 210-P-9's attack and surface craft are sent to investigate. Samples of the slick are examined and determined to be non-petroleum based and organic in nature. No wreckage of any kind is ever found.
  • October 15, 1943 - The Commander, Caribbean Sea Frontier, Rear Admiral Arthur B. Cook, USN initiates a Board of Investigation (BOI), in order to examine the facts while they are still fresh in everyone's mind. The BOI had the legal authority to administer oaths to witnesses. The Senior Member of the board was Captain Harry D. McHenry, USN. It was conducted locally at Naval Operating Base Guantanamo Bay, Cuba.
  • October 24, 1943 - With no hope remaining that the submarine might arrive in Coco Solo, the U.S. Navy reluctantly but officially declares the USS Dorado (SS-248) as overdue and presumed lost.
  • October 26, 1943 - The BOI is concluded. The final opinions reached were that the sub described by 210-P-9’s crew imply a German U-boat was attacked, that both submarine sightings were likely the same U-boat, and that no damage was achieved by the attack by 210-P-9 due to the lack of evidence of oil or debris. Later reviews of the BOI give the appearance that the inquiry was rushed and incomplete, and while the facts that it documented are helpful, the conclusions reached seem unsubstantiated and murky.
  • October 26, 1943 - On the same day that the BOI is concluded, under the authority of the Commander in Chief, U.S. Fleet and Chief of Naval Operations Admiral Ernest J. King, a formal Court of Inquiry (COI) is convened in Washington, DC. It carries the full weight of Navy Regulations and oversight at the highest levels of the Department of the Navy. The court is lead by respected submariner Admiral Thomas C. Hart, USN, who was called back to active duty from retirement to lead the court. Commander John L. Burnside, Jr., a submariner, is appointed as judge advocate. The inquiry lasts until November 20 and is as thorough and complete as was possible at that point in the war. In the end, it comes to some surprisingly different conclusions than the BOI. The COI report opines "That it is highly probable that USS DORADO was lost through the attack by plane No. 210-P-9." Although affirming that the "pilot was not in error in deciding to attack", they found that the crew of 210-P-9 was not properly trained in matters of German or U.S. submarine identification, or of submarine sanctuary zone doctrine such as the submarine's use of zig-zagging or freedom of range to operate within the zone.
  • September 13, 1945 - After the conclusion of the war a thorough review of German records concerning this incident was possible and a memorandum was provided to Admiral King, the Chief of Naval Operations (CNO). U-214’s patrol log reported "a bright yellow light on the horizon" at the vicinity and time of 210-P-9’s depth charge attack (which was considered to be 210-P-9’s flare) and of opening fire two hours later on 210-P-9. No other U-boats were in the area at the time (within 800 nm). It concluded that 210-P-9’s first attack was "not on U-214 nor any other German U-Boat" and further stated that "USS DORADO was not sunk by German U-Boat".

Bottom line

So, with everything that has been put forth on this page, we feel that it is helpful to summarize some pertinent facts and end with logic based conclusions.
  • Only two nations were operating submarines in the Caribbean in October of 1943: the United States Navy and the Kriegsmarine of Germany.
  • No other U.S. submarine was in the Caribbean on October 12, 1943, and the only German U-boat within 800 nautical miles of the scene was U-214.
  • Based on the scope of her MOVORD, Dorado should have been in the central Caribbean on the night of October 12, 1943.
  • Despite acknowledged deficiencies in training for the crew of 210-P-9 in submarine identification, and despite the brief glimpse of the target prior to the release of ordnance, there is an extremely high probability that they bombed, at the very minimum, a "submarine like object" at 8:51 pm on the night of October 12, 1943.
  • The submarine like object bombed by 210-P-9 during the first attack that night WAS NOT U-214 or any other U-boat.
  • Weather played no direct role in the loss of Dorado.
  • It is highly unlikely, given the level of experience, training, and sea trial evaluations of Dorado that she was lost SOLELY to equipment malfunction or operational accident.
  • Dorado was not lost by direct attack by a German U-boat.
  • Dorado DID NOT strike one of the mines laid by U-214 near the entrance to the Panama Canal, and there is only a vanishingly small chance that she struck the lone type EMS 1 mine set adrift by U-214 on the evening of October 12.
  • As far as can be determined, no radio messages of any type were received from Dorado at any station.
  • Dorado never arrived for her rendezvous at Point George, and no relevant debris or confirmed oil/fuel slick was ever found.

Therefore, the precipitating event in the loss of USS Dorado (SS-248) was the bombing by aircraft 210-P-9 at 8:51 pm on the night of October 12, 1943. Dorado likely sank in the vicinity of the attack.

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