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0n the first patrol of the USS S-31 off the Paramishiro Islands in the North Pacific. a large ship appeared out of the ever present fog. close aboard – with avoiding action necessary for the S-31 to avoid a collision. Having radar would have eliminated this embarrassing wartime situation.

Returning to San Diego in late 1942. the S-31 had an SJ radar with an A-scope presentation. installed.

Later. while acting as a training submarine at Espiritu Santos. and in combination with this chore, the S-31 tracked. with her new SJ radar. a good many warships as they came and went from this refit base in Noumea. Caledonia. One of those ships. the USS SOUTH DAKOTA, our newest battleship at that time. brought into port an ex-submariner who was eager to get back into submarine duty. Chief Radio Electrician Dolan had cruised with the SOUTH DAKOTA since her commissioning and knew that this battleship had the latest electronic equipment on board. the latest radars and the latest communications gear. Fortunately. he was transferred to the S-31 because of a vacancy we had in our crew. Dolan knew there were spare General Electric Plan Position Indicator (PPI) scopes on board which would never be used and were just what the S-31 should have to greatly improve her radar readouts. Hence, along with Chief Dolan, a plan was developed to purloin a spare PPI console from the battleship and bring it aboard the S-31. The plan called for a midnight snatch, or “an approprialing for one’s own use without proper authorization” a spare part, for which a forged requisition was duly left behind on expropriating the spare PPI console.

The deed. though clandestine in nature, was easily done and a G.E. PPI console was quickly brought back to the S-31, on a hot night in June of 1943. This all sounds real simple, but the rest of the story gets far more complicated.

Upon delivery, it was discovered that the measurements of the console, prior to bringing it aboard, had been in error by an eighth of an inch. It would not pass through the conning tower of the S-31. Every conceivable method was tried in order to fit the console through other hatches on board the submarine — all without success. Fmally, since the decision had been made that the PPI was absolutely necessary, it was agreed that it would have to be chopped up in order to get it into the boat; then it would have to be re-assembled after all parts had been struck below. Hack saws, chisels, screw-drivers, soldering irons, pliers and name tags were obtained and the work was started. On each console strength member, as it was cut, a colored name tag was attached in order to match up the joints when re-assembly was attempted. Likewise, each wire connector which had to be cut was tagged. Finally, the entire PPI console was deposited in the control room of the S-31 because the small S-hoat conning tower was not large enough to hold the assembled PPI. Then the work really started. After some fifty hours of exceptional effort on the part of Ensign E. I. Malone and Radarman 3/c Reinsch, the console was re-assembled and made ready for electrical hookup and testing.

It was discovered, however, that a compatibility electronics problem was just commencing. The SJ radar was a Western Electric product, while the PPI scope was a General Electric product It was then belatedly discovered that different voltage supplies, different frequencies, and different components were involved. Even though neither Malone nor Reinsch were particularly experienced in the fundamentals of the G.E radar, they rapidly acquired the knowledge for combining the differences between the two systems by substituting resistors and capacitors, adjusting the two sync voltages, substituting relays, and inserting delay lines where necessary in order to utilize a common frequency. In the space of sleepless application, they were ready to test their jury rigged system.

As in any new radar equipment of those days, warnings had been issued as to the danger of overloading a magnetron. Even though the “maggie” of this period was rated at only a half a megawatt, this was something to contend with since explosions and implosions had been recorded and written up in publications issued by the Bureau of Ships. Therefore, after the proper precautions had been observed, all hands were ordered to clear the control room when the system was energized.

Nothing untoward occurred. It seemed that our PPI was in business. Aside from such factors as the PPI not tracking with the A-scope of the SJ and the sea return of the PPI being of unusual proportions, everything seemed to operate well. With a few more adjustments and substitutions of various components by the trial and error me.!hod, all hands were truly amazed when the hand crank mechanism of the SJ finally influenced the PPI magnetic field to follow it with a reasonable amount of accuracy.

With the new SJ system under control, the modification team were given two-day passes to catch up on lost sleep. In the meantime, the skipper, a USNA graduate, who felt he could practice his mechanical and electrical ability on the basis of his eight year old BS degree, decided that a fully electrical training gear was much better than the hand-train presently installed. So, a half horse power motor was also filched from a warship and a spur gear was designed which could be inserted in the hand-crank-to-motor system in order to eventually provide a completely automatic system. This reduced the need for an additional watch-stander in the conning tower. It turned out, however, that the skipper did not remember very much about cutting gears. He designed the teeth from an old steam engineering text book found on board. His design was then sent over to the USS ARGONNE, a destroyer tender, but the ARGONNE’S repair officer sent word back that, with the gear ratio specified, the spur gear would not work. However after several boat rides to and from the tender, a satisfactory gear was designed, manufactured and installed. Even though it was noisier than a threshing machine, it worked admirably. Later modifications moreover quieted the mechanical aspects of the assembly.

It was believed that the SJ’s new radar system would enable fleet-boat skippers to conduct night surface attacks without forcing them to stay on the bridge. In fact, a more effective fire control solution was obtained with the C.O. in the conning tower watching his PPI scope and the IDC simultaneously.

Thus, the marriage of the Western Electric SJ radar with the General Electric PPI scope in a submarine came into being. The concept, with a detailed design description, was submitted to the Commander Submarine Force. He then put qualified engineers on the job who provided the radar attack system which was used so successfully for the duration of World War IT in all U.S. submarines.

Mike Sellars 

Naval Submarine League

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