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Builder's Trials

Once the construction of a submarine was nearly complete, preparations were made for the builder's trials that would help test the boat's systems and to ensure there were no serious defects prior to the preliminary trials and then commissioning.

Each submarine would ease its way down the Manitowoc River towards Lake Michigan and then head for the assigned test area with a mixture of the crew, the trial board and shipyard personnel manning the various stations aboard. Pumps, valves, steering gear and the bow and stern diving planes would be tested along with the hydraulic systems as well as different combinations of the diesel engines and electric motors powered by the batteries.

The first test dive was, in general, performed while the submarine was stationary and with a trim that was lighter than normal so as to be on the safe side. With a green board, the main ballast tanks would be flooded, which would only partially submerge the boat because of the light trim. Adjustments would be made to the bow and stern buoyancy tanks to make sure the sub was on an even keel and then finally the auxiliary tanks would be flooded, giving the boat a negative buoyancy causing it to fully submerge beneath the surface of Lake Michigan. Minor adjustments were made until the trim was finally corrected and the results were noted.

Running submerged, the crew would continue testing the machinery and check for leaks or other defects throughout each compartment. Satisfied that everything was working as it should, the sub would surface and head back to the shipyard and a critique of the day's tests.

Over the next several days, the boat would be tested on running dives, full power and battery tests as well as the determination of its tactical turning diameter with adjustments and last minute installations continuing while the boat was dockside.

By far one of the most important tests during the builder's trials was the dive to the test depth of 300 feet or 400 for the Balao class boats at a suitable area located in the middle of the lake and opposite Sheboygan, Wisconsin.

The boat would submerge by 50 foot increments and then level off so that readings could be taken of the hull's deflection and ensure that it was within the acceptable limits. Machinery, especially the reduction gears, was also checked to make sure that their alignment was not affected by the increased water pressure on the hull.

When the test depth was reached, the submarine would surface and the hull checked again to see that it had returned to its original shape and any permanent distortion was within acceptable limits.

The last leg of the builder's trials would be completed the next day including running dives that were made within the standard dive time and a full power battery test. Once completed, a recommendation would be made by the Supervisor of Shipbuilding to the Navy Department that the submarine was ready for trials under the Trial Board.

Board Trials

The trial board was made up of Navy personnel and overseen by a flag officer. While the builder's trials checked the quality of the construction and ensured it met the standards of the contract, the board trials went a step further and indicated whether or not the boat was ready to join the fleet.

The numerous tests would take a couple of days to complete under the wary eyes of the board and would include maneuvering both surfaced and submerged, steering gear trials, diving place trials and periscope vibration tests.

When the submarines entered the Manitowoc River after completing their board trials, a broom would be lashed to the periscope indicating that it had passed all tests with flying colors. In comparison to other yards, the Manitowoc boats typically had less than six items found by the trial board that needed correction before they could be commissioned. The Manitowoc Shipbuilding Company would eventually be awarded six Navy "E" Awards indicating its reputation for production excellence.

Commissioning & Crew Training On Lake Michigan

Members of the crew would arrive in Manitowoc at various times to help during its construction and fitting out, with the remainder of the crew reporting aboard just prior to its commissioning.

Because several boats were being built at any one time, the crews would support each other with the numerous tasks they were faced with in order make sure their boat would pass trials and ready itself for war in the Pacific.

Other than the USS MENHADEN (SS-377)*, each crew was a mixture of experienced submariners, experienced but nonqualified sailors and recruits fresh from the Naval training center who had never even seen a warship before reporting aboard.

The plankowners of the USS MENHADEN, commanded by Cmdr. David McClintock, were made up by the entire crew of the USS DARTER (SS-227), which had been lost in action without loss of life when it became grounded on Bombay Shoal in the Palawan Passage during a surface attack on the Japanese task force headed for the Leyte Gulf in October 1944.

Some recruits in other areas of the military are generally treated with indifference or outright contempt, but aboard a submarine, a non-qualified crew member was a liability and would continue to be so until they had learned every system aboard. But rather then isolate the recruits, submariners would quickly indoctrinate them and push them to finish their qualifications because the sooner the recruits become a part of the crew, the better off the entire boat would be while out on patrol.

Immediately after the commissioning ceremony, the crew of the submarine would begin transferring their personal gear as well as outfitting the submarine with stores and spare parts from the dockside facilities which would typically last about a week. At the same time the crew would become familiar with their watch stations and be run through numerous drills until they were well acquainted with the rhythms of a submarine.

Communications between the shipyard and the submarine while it was out on the lake during training was handled by having the radio equipment of a boat still under construction placed in the Submarine Office ashore and then manned by the personnel of the next sub to be commissioned, giving them some valuable training time. Once the captain of the submarine felt that the crew was ready, he would begin the shakedown cruise to further test the men and the submarine over the next several days out on Lake Michigan.

Operating on Lake Michigan presented the crews with some unique differences and/or problems not found in the open ocean. One of biggest differences for the submariners was diving in the fresh water of the Great Lakes, which caused the subs to submerge much more quickly and easily because of the lack of salinity in the water.

Another effect of operating in fresh water for the submarines was experienced by the crews that trained during the winter months when their boats would become encased in a thick layer of ice. Because the waves on Lake Michigan were short and steep the submarines weren't able to ride them out like they would on the ocean, but instead cut through the waves causing a large amount of spray which would then freeze once it hit the deck and superstructure.

The problem with the heavy icing was the most apparent with the PETO on the first shakedown cruise on the lake when the temperature had dropped to 15 degrees. Shortly after the order to dive had been given, the diving officer shouted a warning that the main induction valve had not closed.

Quickly ordering the ballast tanks to be blown, the PETO surfaced safely and the crew continued to try and close the main induction valve with no luck.

An inspection of the valve located in the conning tower fairwater found that the valve was encased in a solid mass of ice and would not close. Only after chipping away at the ice was the valve able to close, allowing the boat to be submerged. From then on, the crews of other subs would regularly chip away the ice that would form on the vessel, eliminating the problem faced by the PETO.

The Quirks Of Lake Michigan

The PETO observed another difference with operating in fresh water, but one that wasn't so hazardous. While the radio operator was copying a schedule being transmitted from Annapolis, the PETO submerged beneath the lake. Normally contact would be lost during this time, but the radio operator continued to receive the message even though the sub was at periscope depth. The same interesting phenomena would be experienced by succeeding boats.

The lack of strong navigational lights along the Lake Michigan coastline also presented a problem for the crews. Many times the only lights were weak beacons on the breakwaters that became lost in the lights of the city. Navigating with such rough estimates, the submariners jokingly admitted that they were better off determining their position by being able to recognize the taverns and beer signs that dotted the shore of the lake.

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