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=== <big>Design and Construction Notes</big> ===
=== <big>Design and Construction Notes</big> ===
<div style="text-align: justify;"><span style="color:#00008B">The twelve submarines of the Tambor and Gar classes were the high water mark of pre-war submarine construction in the USN. Although authorized in two different fiscal years (FY-39 & 40), the six boats each of the Tambor and Gar classes were actually identical in design with no significant differences between the two groups. They will be treated as one class here on PigBoats. The design of these boats rolled into one all of the lessons that had been learned during the 20 years of peacetime trial and error development, and their origin dates back to the beginning of the V-class in 1921. The only criticisms of these boats was that they had been optimized for peacetime cruising and thus needed modifications to be optimal to fight the war they faced. They were also officially rated with only a 250-foot test depth, an overly conservative value that would change with the follow-on Gato class.
<div style="text-align: justify;"><span style="color:#00008B">The twelve submarines of the Tambor and Gar classes were the high water mark of pre-war submarine construction in the USN. Although authorized in two different fiscal years (FY-39 & 40), the six boats each of the Tambor and Gar classes were actually identical in design with no significant differences between the two groups. They will be treated as one class here on PigBoats. The design of these boats rolled into one all of the lessons that had been learned during the 20 years of peacetime trial and error development, and their origin dates back to the beginning of the V-class in 1921. They were well liked and rugged in design and quite advanced for the time. There were however, three criticisms of these boats. Firstly, their design had been optimized for peacetime cruising and thus needed modifications to be optimal to fight the war they faced. Second, they were officially rated with only a 250-foot test depth, an overly conservative value that initially limited underwater evasion tactics. Third, all four engines were contained in one large room, and there were fears of catastrophic flooding should the engine room be breached. In the end these issues were relatively minor in nature, and would be corrected in the follow-on Gato-class. All of these boats turned in superb service during the war.
Maintaining the construction trend that had started with the Porpoise class, the Tambor/Gars were divided up for construction between the Portsmouth Navy Yard (four boats), Electric Boat (six boats), and the Mare Island Navy Yard (two boats). Based on repeated calls by the Submarine Officers Conference for a heavier armament, these boats were equipped with six bow and four stern 21" torpedo tubes, carrying a total of 24 torpedoes. For gun armament, they were built with a 3"/50 caliber Mk 17 gun and one or two Browning M2 .50 caliber water-cooled machine guns. Starting in the summer of 1942, six of these boats (Tambor, Thresher, Tuna, Gar, Grayback, and Grayling) were refitted to carry a much larger and more powerful 5"/51 caliber Mk 9 gun, located on an expanded sponson on the aft deck. Three of the guns had been originally installed on the earlier Barracuda-class fleet boats, the other three were production spares. Gun armament varied considerably during the war, with the boats that did not get the big gun getting a 4"/50 caliber Mk 9 gun, taken mostly from older S-boats.
Maintaining the construction trend that had started with the Porpoise class, the Tambor/Gars were divided up for construction between the Portsmouth Navy Yard (four boats), Electric Boat (six boats), and the Mare Island Navy Yard (two boats). Based on repeated calls by the Submarine Officers Conference for a heavier armament, these boats were equipped with six bow and four stern 21" torpedo tubes, carrying a total of 24 torpedoes. For gun armament, they were built with a 3"/50 caliber Mk 17 gun and one or two Browning M2 .50 caliber water-cooled machine guns. Starting in the summer of 1942, six of these boats (Tambor, Thresher, Tuna, Gar, Grayback, and Grayling) were refitted to carry a much larger and more powerful 5"/51 caliber Mk 9 gun, located on an expanded sponson on the aft deck. Three of the guns had been originally installed on the earlier Barracuda-class fleet boats, the other three were production spares. Gun armament varied considerably during the war, with the boats that did not get the big gun getting a 4"/50 caliber Mk 9 gun, taken mostly from older S-boats.
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These boats were in the thick of the fight against the Japanese from the first day of the war. Seven of them (marked by a *) and their brave crews were lost in action and are considered to be "on eternal patrol".
These boats were in the thick of the fight against the Japanese from the first day of the war. Seven of them (marked by a *) and their brave crews were lost in action and are considered to be "on eternal patrol".
As with all of the pre-war built fleet submarines, once the war started their external appearance was heavily modified as experience was gained. These changes came fast and often, and it is easy to be confused by it all. The authors highly recommend that you read the Visual Guide article posted [[Visual Guide|here]].
As with all of the pre-war built fleet submarines, once the war started their external appearance was heavily modified as experience was gained. These changes came fast and often, and it is easy to be confused by it all. The authors highly recommend that you read the Visual Guide article posted [https://pigboats.com/images/3/3b/A_VISUAL_GUIDE_TO_THE_FLEET_SUBMARINES_PART_4_GATO_CLASS_2024.pdf '''at this link'''].
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'''Special Note'''... PigBoats.COM normally adheres to a 1940 date for a boat to be included on these pages. We are making a small exception here. We will include all twelve of the Tambor/Gar class boats for continuity purposes even though Grayback and Gudgeon technically fall outside of that date window.</span></div>
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[[File:Thresher near bridge.jpg|left|500px|U.S. Navy photo. An original print in the private collection of Ric Hedman.]]
[[File:Thresher near bridge.jpg|left|500px|U.S. Navy photo. An original print in the private collection of Ric Hedman.]]
<div style="text-align: justify;"><span style="color:#00008B">Thresher passing under the U.S. Route 1 Bridge spanning the Thames River between New London and Groton, CT. The date is 1940. Judging by the wake she is running at approximately eight knots, but unusually she is running on the battery. No diesel exhaust or overboards are seen. It looks like she is headed up river towards Submarine Base New London. This would explain the large number of men topside. They are up topside anticipating their return home.</span>
<div style="text-align: justify;"><span style="color:#00008B">Thresher passing under the U.S. Route 1 Bridge spanning the Thames River between New London and Groton, CT. The date is 1940. Judging by the wake she is running at approximately six knots, but unusually she is running on the battery. No diesel exhaust or overboards are seen. It looks like she is headed upriver towards Submarine Base New London. This would explain the large number of men topside. They are anticipating their return home.</span>
The twelve submarines of the Tambor and Gar classes were the high water mark of pre-war submarine construction in the USN. Although authorized in two different fiscal years (FY-39 & 40), the six boats each of the Tambor and Gar classes were actually identical in design with no significant differences between the two groups. They will be treated as one class here on PigBoats. The design of these boats rolled into one all of the lessons that had been learned during the 20 years of peacetime trial and error development, and their origin dates back to the beginning of the V-class in 1921. They were well liked and rugged in design and quite advanced for the time. There were however, three criticisms of these boats. Firstly, their design had been optimized for peacetime cruising and thus needed modifications to be optimal to fight the war they faced. Second, they were officially rated with only a 250-foot test depth, an overly conservative value that initially limited underwater evasion tactics. Third, all four engines were contained in one large room, and there were fears of catastrophic flooding should the engine room be breached. In the end these issues were relatively minor in nature, and would be corrected in the follow-on Gato-class. All of these boats turned in superb service during the war.
Maintaining the construction trend that had started with the Porpoise class, the Tambor/Gars were divided up for construction between the Portsmouth Navy Yard (four boats), Electric Boat (six boats), and the Mare Island Navy Yard (two boats). Based on repeated calls by the Submarine Officers Conference for a heavier armament, these boats were equipped with six bow and four stern 21" torpedo tubes, carrying a total of 24 torpedoes. For gun armament, they were built with a 3"/50 caliber Mk 17 gun and one or two Browning M2 .50 caliber water-cooled machine guns. Starting in the summer of 1942, six of these boats (Tambor, Thresher, Tuna, Gar, Grayback, and Grayling) were refitted to carry a much larger and more powerful 5"/51 caliber Mk 9 gun, located on an expanded sponson on the aft deck. Three of the guns had been originally installed on the earlier Barracuda-class fleet boats, the other three were production spares. Gun armament varied considerably during the war, with the boats that did not get the big gun getting a 4"/50 caliber Mk 9 gun, taken mostly from older S-boats.
These boats were in the thick of the fight against the Japanese from the first day of the war. Seven of them (marked by a *) and their brave crews were lost in action and are considered to be "on eternal patrol".
As with all of the pre-war built fleet submarines, once the war started their external appearance was heavily modified as experience was gained. These changes came fast and often, and it is easy to be confused by it all. The authors highly recommend that you read the Visual Guide article posted at this link.
Tambor (SS-198)
National Archives photo.
Tambor underway on builder's trials off Provincetown, MA., April 8, 1940. This is a very typical appearance for the pre-war boats. The Tambor/Gar class boats, along with a few of the early Gatos, were the last boats built with a periscope station in the control room. This is indicated by the stepped appearance of the periscope shears. Both of the periscopes are 40-foot long models, but the eyepiece of #1 scope is in the control room giving it the external appearance of being shorter. The Electric Boat built versions of this class had a unique modification. The towing fairlead (bullnose) was faired into the tip of the bow. The boats built at Navy yards had the older style above deck bullnose (see Triton and Tuna photo below.)
Tautog underway in Cape Cod Bay after running the measured mile off Provincetown, MA., July 1940. This photo highlights one of the prime differences between the Tambor/Gar-class boats and earlier classes. The superstructure now ends short of the stern. On the aft deck is the 3"/50 caliber Mk 17 gun. The mount is quite tall and is visually distinctive. The intention here was to provide the ability to greatly elevate the gun for use with fused anti-aircraft rounds. In practice the boats were rarely supplied with such rounds, as it was felt that taking on aircraft was far too dangerous.
U.S. Navy photo. An original print in the private collection of Ric Hedman.
Thresher passing under the U.S. Route 1 Bridge spanning the Thames River between New London and Groton, CT. The date is 1940. Judging by the wake she is running at approximately six knots, but unusually she is running on the battery. No diesel exhaust or overboards are seen. It looks like she is headed upriver towards Submarine Base New London. This would explain the large number of men topside. They are anticipating their return home.
An often seen but classic photo of the Triton on maneuvers in the Caribbean in early 1941. One of her sister boats is in the background, likely Trout. The Tambor/Gar-class submarines were the epitome of everything that had been learned about submarine technology and tactics over the previous 20 years of trial and error, and this picture amply illustrates the level to which this development reached in the final months of peace. These were handsome boats and they cut a fine figure at sea. Note the above deck towing fairlead (aka bullnose) at the tip of the bow. The EB version was faired into the deck tip.
Two months after her commissioning, Tuna was caught by a photographer in San Francisco Bay. Tuna was one of two boats of this class built at the Mare Island Navy Yard. Unusually, Tuna is showing some minor damage to the bottom edge of her superstructure, between the folded bow planes and the conning tower fairwater. A small portion of the bottom edge has been pushed in, and two wedges are keeping it from bending further in a sea state. The damage may have been caused by a tug impacting the superstructure. It is possible Tuna is headed back to the yard for a fix. One other interesting feature is the hook shaped mount for a water-cooled Browning M2 .50 caliber machine gun atop the covered pilothouse on the front of the conning tower fairwater. On some other boats this mount was on the forward deck. Placing the mount here allowed the gunner a very wide arc of fire. There was another mount on the "cigarette deck" aft of the bridge. That mount is not seen here because of the bulwark surrounding it. The .50 caliber gun was small enough that it was dismounted and taken below before diving.
Photo courtesy of the Submarine Force Library & Museum.
A brand new but not yet commissioned Gar alongside the fitting out pier at the Electric Boat Company, Groton, CT., April 1941. She is essentially complete at this point, and is just awaiting some finishing touches before the Navy accepts her into service. This photo gives a very good view of the faired in bullnose of the EB design. Grampus (SS-207) sits at the next pier over.
Grampus patiently waiting to get her picture taken, March 26, 1941. The location is probably the waters off Provincetown, MA. in Cape Cod Bay. She has been running her builder's trials, a series of tests run by Electric Boat personnel designed to wring out all systems. Discrepancies found will be corrected once they return to the yard. At this point the boat is still under the ownership of EB. Elements of her Navy crew would be aboard to observe and train, but she is under the full control of EB. An accommodation ladder has been rigged up on the port side, undoubtedly to pick up the photographer from the trailing small boat.
USN photo 6139-43, courtesy of Darryl L. Baker via Navsource.org
Grayback viewed here broad on the starboard side in San Francisco Bay after her last wartime overhaul, August 26, 1943. Her conning tower fairwater sports a Mod 3 Long Bridge configuration, with the forward and aft portions cut away with 20mm guns added on those gun decks, SJ radar added to the front of the periscope shears and SD added aft of the shears. Grayback is one of the six Tambor/Gar-class boats that received the large and powerful 5"/51 caliber Mk 9 gun. The gun was large enough that an expanded sponson had to be built around the aft gun mount to give the gun crew enough deck space to train the gun.
USS Grayling making a speed run off Portsmouth, NH., November 12, 1941 in those last days before the war. She is making nearly her full speed, 18.2 knots and is throwing up quite a bow wave. Grayling had been in commission 8½ months at this point, and shortly after this photo was taken she would head to the Pacific to join the fleet. She was in San Diego when the war started.
Photo 08 06 023289 courtesy of the Boston Public Library, Leslie Jones Collection
Grenadier shortly after launch from the Portsmouth Navy Yard, Kittery, ME. on a cold but calm November 29, 1940. Much work remains to be done, including the installation of her periscope shears and masts. This photo gives a good view of the Government design for the towing fairlead bullnose, which is the old style above deck steel ring.
Photo 5767-43 from NARA San Francisco via Tracy White and Navsource.org
An excellent starboard side view of Gudgeon, August 7, 1943 after an overhaul and modernization at Mare Island. She is very similar to Grayback at this time, with a Mod 3 Long Bridge conning tower fairwater variation. The SJ radar mast is prominent above the bridge. Both periscopes are lowered but the SD radar mast is fully raised. The circular loop aft of the SD mast is a radio direction finder (RDF) loop which could be used in an intelligence role or as a navigation aid. The expanded sponson for the big 5"/51 caliber deck gun is quite apparent.
