Control room looking forward along the starboard side. The primary gyrocompass is the black barrel shaped object just inside the door. The black box directly aft and next to the helm I believe to be the gyrocompass repeater that took inputs from the gyro and indicated the course you were steering.
In the center above the helm wheel is the rudder angle indicator, flanked on both sides by the engine order telegraphs. The lever on the vertical shaft was used to engage/disengage the control room helm from the conning tower and bridge helm. Which helm would have been the primary station for submerged operations? We would lean towards the conning tower, but that opinion might be flavored by what was done in combat in WWII and may not necessarily reflect pre-war 1930's practice.
Large levers next to helm are for switching from normal hydraulic to hand hydraulic. In hand hydraulic you spun the wheel to develop hydraulic pressure and this was a very laborious process.
Oval hatch in deck next to helm most likely leads to a store room. Note speaking tube to conning tower above the helm.
US Navy Photo Contributed by Roger Torgeson
The view looking aft from the front of the Control Room. The motor on the deck in the center is suspected to be the hoist motor for the Control Room and Conning Tower periscopes. The location of the control room scope does not seem to be in a good place. It is at the far aft end of the room behind the ladder to the Conning Tower and cut off from direct view of the helm.
Open grate in the deck leads most likely to the Pump Room and the grating is for drainage of any flooding into the Pump Room, where it can be pumped out through the main drainage system.
The square hatch is suspected to be the access to the Cold Room/Freezer. The padlock seen on the hatch seems to correspond to other food storage areas with padlocks making us think this is that space. Drawings indicate that the Cold Room/Freezer was directly under the middle of the Control Room.
On the right edge of the photo, just below the polished bell of the speaking tube, and above the battle lantern, is the mechanical linkage for the bow planes coming out of the angled enclosure just above and to the right of the bow planes control wheel.
US Navy Photo Contributed by Roger Torgeson
Crewman, possibly the below decks watch. His name has been lost to time. This is the only photo in the whole sequence showing crew aboard. Date is July 3, 1933. Hopefully he had the next day off to celebrate.
US Navy Photo Contributed by Roger Torgeson
A look at the after starboard corner of the Dolphin Control Room. Electrical panel in the left foreground and next to the door Fuel Oil Ballast Tank transfer piping.
US Navy Photo Contributed by Roger Torgeson
Fuel Ballast Tank Fuel Oil Valves. Several large tags on the handles say "Fuel Oil Do Not Blow"
US Navy Photo Contributed by Roger Torgeson
A hull opening indicator, commonly called a Christmas Tree by submarine sailors due to its red and green lights, sits next to the ladder up to the conning tower. View is looking aft and to port.
US Navy Photo Contributed by Roger Torgeson
Close up of the aft of two Christmas Trees. Another is seen on the forward bulkhead of the control room. "OP" = open, "SH" = shut. This gives the status of all hull openings and is a quick reference to the crew indicating whether the boat is watertight prior to diving. Shut is the preferred position so it will show in the color green. An open valve or fitting is usually bad for a diving submarine so the Open indicators will have a red light.
US Navy Photo Contributed by Roger Torgeson
Stern planes control wheel on the left, bow planes wheel on the right. Two shallow water depth gauges with the deep water gauge in the center. Horizontal bubble clinometer gauges for angle. Rudder angle indicator is probably for the Diving Officer to keep in the loop.
The large, angled sheet metal enclosures, to the left and right of the stern planes and bow planes wheels, cover the mechanical linkages for the stern and bow planes control rods.
US Navy Photo Contributed by Roger Torgeson
Closeup of the angle clinometers than indicate whether the boat has an up or down angle, and how much. There is also an indicator for the angle position of the bow and stern planes. The circular gauge in the center is a rudder angle indicator. How much rudder is on will affect the up or down angle of the boat. Large amounts of rudder tend to make the stern squat downward.
US Navy Photo Contributed by Roger Torgeson
A closeup of the depth gauges. The two large ones are shallow water gauges, which go to only 150 feet. The smaller one in the center is the deep water gauge, calibrated to what appears to be 400 feet. Depth is measured to the keel.
US Navy Photo Contributed by Roger Torgeson
Another view of the control room looking forward this time showing some detail in the forward starboard corner of the room. The enclosed cabinet in the far corner is probably an electrical equipment storage space. Spare parts, fuses, tubes, etc. It's purpose is not known for sure at the present time.
US Navy Photo Contributed by Roger Torgeson
A second Christmas Tree appears to be on the left of the photo. Open and Shut indicators are evident but no location names can be read. Notice the engine order telegraphs. The lower set are used by the helmsman to send orders aft, the upper set indicates that Maneuvering has acknowledged the order. A rudder angle indicator is in the center. The vertical rod and lever are for engaging/disengaging the conning tower and bridge helm wheels. A conical voice tube with a shut off valve connects the helmsman to the Officer of the Deck on the bridge and to maneuvering.
US Navy Photo Contributed by Roger Torgeson
Close up of the hydraulic Vent/Flood control panel. This operates the hydraulics for opening the vents and Kingston valves for the submarine's ballast and auxiliary tankage. It seems that only the Main Middle Ballast Tanks (Port and Starboard), and the Safety tank have Kingston valves. The last signage on the right has the word "Ventilation" but we do not know if there was any other description that went with this and why was it on a diving valve manifold? Perhaps this was a valve for inboard ventilation?
US Navy Photo Contributed by Roger Torgeson
Control room looking to starboard and aft. In many respects this is the general layout for the starboard side of control rooms throughout the coming sequence of submarines through WW II and after. The type of equipment will change with newer and more modern versions as time passes but this was the template for the future. Electrical panels at the left will become enclosed to prevent short due to condensation and for crew safety as time went on.
Just to the right of these panels is a barometer. This was important to letting the crew know what was happening with weather but also in letting them know the submarine was closed up properly for diving. When all hatches and valves were closed a small amount of air was bled into the submarine and the barometer would register this pressure change. If everything was closed properly the pressure would not change. The report; "Pressure in the boat", would signal all was well and the dive could proceed. An important piece of equipment indeed.
Moving right we see the row of gauges for the air system and air banks and various pressures. The manifold seen below these gauges is the trim manifold which ports internal ballasting water around the boat. Air system valves are to the right and below of this manifold.
The row of large valves and piping seen in the overhead are associated with the Fuel Ballast Tank System.
US Navy Photo Contributed by Roger Torgeson
Air bank gauges and manifolds with the variable water trim manifold in the center. Tucked in behind at the top of the trim manifold can be seen two "T" handle wrenches for operating this manifold.
Labels on the trim manifold, top row of valves: "Aux Bal, Tk No1 Blow", "Aux Bal, Tk No2 Blow", "For'd Trim Tank Blow", "Aft Trim Tank Blow".
Bottom Row: "Aux Bal, Tk No1 Vent", "Aux Bal, Tk No2 Vent", "For'd Trim Tank Vent", "Aft Trim Tank Vent".
The three valve handles on the left read, Top: "200# Air For'd" and the bottom one reads "200# Air Aft". The center handle has nothing readable except "open"
The bottom large handle says "200# Air From Reducer" Meaning Higher pressure air was sent through a reducer to become 200 pound air.
US Navy Photo Contributed by Roger Torgeson
The heavy casting of this manifold indicates that it is the high pressure air manifold. In looking at the gauge faces numbers can be seen that have pressures from 2000 to 4000 PSI on them.
US Navy Photo Contributed by Roger Torgeson
Low pressure air manifold.
US Navy Photo Contributed by Roger Torgeson
These two valve handles are seen in the overhead of the control room in the large scale photo above, directly above the trim manifold.
This is the earliest mentions we have seen to anything dealing with a hydraulic system on a submarine. The valve wheel says "Hydraulic Refill Supply". The other valve is unreadable. What this hydraulic system ran is not known at this time.
US Navy Photo Contributed by Roger Torgeson
This valve, also in the overhead above the trim manifold, is the conning tower flood valve. If for some reason, such as fire or escape procedures opening this valve would flood seawater into the conning tower, allowing it to be used in a fashion similar to an escape trunk.
US Navy Photo Contributed by Roger Torgeson
Pump Room Starboard Side
The control room compartment has two levels. Below the deck is the pump room, containing the trim pump used to move ballast water to various tanks, and the refrigeration machinery for the cold storage room. This photo is looking to starboard and shows the trim pump. The location corresponds with the with the trim manifold located directly above in the control room.
US Navy Photo Contributed by Roger Torgeson
Closeup of the tachometer for the trim pump.
US Navy Photo Contributed by Roger Torgeson
Closeup of the manufacturer's plate on the trim pump. It is from the Electrodynamic Co., Bayonne, NJ. The rest is illegible.
US Navy Photo Contributed by Roger Torgeson
Pump Room Port Side
On the port side of the pump room is the "Ice Machine" for refrigeration and freezing in the cold storage room. It was made by the "York Ice Machinery Corp". The York Corp. is still in business today. It should be noted that refrigerated storage for food was a luxury virtually unheard of on submarines in any other of the world's Navies. The long (70 days +) patrols in the warm waters of the Pacific that were anticipated for these fleet boats virtually required refrigerated storage. Without it, food could not be kept fresh for the entire patrol.
US Navy Photo Contributed by Roger Torgeson
Pressure gauge for the York compressor.
US Navy Photo Contributed by Roger Torgeson
View of the port side of the pump room giving a wider angle view. The York compressor is visible in the background. The flask seen in the right foreground could hold a variety of gases including Freon used in the York compressor. Forward is to the right. The Chill box and freezer are also to the right.
The large vertical cylinder seen to the left side is the periscope well for the # 2 periscope.
US Navy Photo Contributed by Roger Torgeson
Cold Storage Room
The cold storage room. It isn't known if this was used as a refrigerator or a freezer. The slabs and sides of meat suggest it could be being used as a refrigerator. A ladder up to the Control Room is seen on the left. The quality of the food on the fleet submarines was excellent and it was envied by most other navies.
US Navy Photo Contributed by Roger Torgeson
Close up of some of the contents. Whole sides and quarters of pork and beef have been placed in the room. It seems as though the cooks had to cut their own steaks and chops unlike today when it all comes pre-cut and prepared.
US Navy Photo Contributed by Roger Torgeson
Close up of the bottom of the room showing wooden crates of poultry and more meats on shelves to the right.