Word was passed "Rig ship for dive" at 0800 DST on 23 May . At this time I took my usual position at the diving control station in the control room and proceeded to check the trim of the Squalus while awaiting the first reports from compartments that they were rigged for the dive. The man stationed at the phones in the control room reported each compartment to me as each compartment completed its rig, whereupon that particular compartment was checked off on the rigging board provided for the purpose, at the diving station. The compartments forward of the control room were checked by Lieut. (jg) Nichols and the compartments aft of the control room were checked by Ens. Patterson. In addition to the reports by telephone, as each individual compartment completed its "rig for dive", Lt. Nichols and Ensign Patterson personally reported to me that their portion of the ship was rigged for dive.
It was approximately 0825 before the ship was rigged, whereupon the word was passed "submerged trial crew take stations". Shortly thereafter word was passed "Observers to take station", since the trial board procedure was going to be rehearsed and all data was to be recorded as on actual trials. At the diving station all main ballast kingstons were operated to check their operation. Following this, all main ballast vents were operated to test them and also to vent all pressure therefrom. Two 2800 pound air banks were cut into the air manifold. The stern planes were tested both by power and by hand. All indicator lights at the hydraulic manifold were indicating properly. Word was then given to the bridge at approximately 0830 "Ship rigged for dive, with the exception of engine exhaust valves, engine and hull inductions, radio antenna trunk, bow planes and conning tower hatch". Word then came from the bridge to rig out bow planes, which were then rigged out and tested. The diving message was sent and the radio antenna trunk secured. Word was passed "standby to dive", which word was relayed by the control room talker to all compartments.
The dive was to be a quick dive from four main engines, with no main ballast kingstons or vents open, until the first diving alarm was sounded. At the sounding of the first diving alarm all main ballast kingstons were opened, followed immediately by opening vents on bow buoyancy, #1 main ballast, #2 main ballast and safety tanks. Bow and stern planes were put on hard dive. About 10 seconds later the indicator lights showed the conning tower hatch closed and the four main engine outboard exhaust valves closed. Telephone reports from the forward and after engine rooms came simultaneously, that all engines were stopped and valves closed. The hull and engine inductions were then closed immediately and indicated such on the indicator board. The air manifold man bled air into the boat until there was a pressure indicated on the barometer. At this time I held up two fingers as the signal for the second diving alarm and at the same time opened the vents on #3 and #4 main ballast tanks. As the C[ommanding]. O[fficer] entered the control room, I reported "pressure in the boat, green board" and proceeded to take the vessel down to 63 feet. The main motors were now driving the vessel at the one-hour, 1280 spec. gravity rate and when I last looked at the revolution indicators they were indicating 220 r.p.m. The dive took on the attitude of an excellent one and as we approached 40 feet and closed all vents. Our maximum diving angle was 9º, and at 45 feet I began to ease the angle off. I kept a close watch on the indicator light board, since I wanted to be ready in all respects to blow in case our high speed drove the vessel down too deep. The hull opening indicators continued green at all times, and both the kingston and vent indicators showed green.
As we approached 50 feet, which was the depth to which the time of the dive was taken, I ordered all diving angle taken off and to level off at 63 feet. The C.O. had been standing alongside me up to this point and as we began to level off he walked to his station at the periscope. We had just commenced leveling off when telephone report came that the after engine room was flooding. I immediately ordered "blow main ballast", followed immediately by "blow safety and bow buoyancy". Another air bank was cut in on the manifold shortly after this. At 80 feet it seemed as though our downward progress had stopped and we had about 14 up angle, but this angle suddenly increased until the bubble was lost and without an definite sensation of going down we settled at 206 feet, with an "up" angle of 11º. Blowing of ballast was stopped when it was certain that no water was left to be blown. Light and power was lost simultaneously with settling on the bottom. Up until the time lights went out, the lights on the indicator board showed no change over their original status at the start of the dive. Emergency lights were lit, but shortly after went out, after which, Gainor reported that he had pulled the disconnected switches in the forward battery tank. Means of further lightening the vessel were discussed and it was decided that the after trim tank was the only tank which would be blown to effect any change. This tank was blown as dry as possible without any change in the vessel's position. Further expenditure of air was not deemed advisable at this time, as it was considered possible that we might aid salvage attempts in getting the vessel to the surface.
All men were equipped with "lungs" and a review of their operation held. Cans of CO2 absorbent were made ready, and the oxygen system was tested up to the Schrader valve connections in the conning tower. A red rocket was fired from the signal ejector and hourly from then on until the [U.S.S.] Sculpin was heard. The telephone buoy was released from the forward torpedo room. Telephone communications was possible forward, but no communications could be gotten with the after section. Slugs of oil were blown out of the toilet bowl periodically to augment the smoke rockets. At no time did any sound come from aft to indicate that there was life there. The crew was instructed to move about as little as possible and aside from getting food, replacing flashlights, replenishing the air or tapping signals, there was little movement.
Soon after settling on the bottom the relief valve on the hydraulic system lifted and oil discharged therefrom. Salt water finally took the place of the oil which indicated a break in the hydraulic system. The forward battery room was investigated and found to be very warm but no indications of chlorine gas. Chlorine gas was present when the 18 men in the control room proceeded to the forward torpedo room after the first [rescue chamber] bell trip left the vessel.
During the emergency and the entire time we were on the bottom, all hands exhibited coolness and precision in carrying out the duties of their stations. Orders of the Commanding Officer were carried out promptly and efficiently. In spite of the low temperature and cramped quarters there were no complaints. A finer quality or higher spirited group of men, than those on the Squalus, will never be surpassed.
Source: USS Squalus file, World War II Command File, Operational Archives Branch, Naval History and Heritage Command, August 2001