Tullibee could use the turbo-electric approach because her single shaft ran at about the same power as those of existing direct-drive diesel-electric submarines. Initially, it was assumed that a scaled-up equivalent would be installed in the new attack submarine (Thresher) [....] The 15,000 SHP of a fast submarine, however, was a different proposition from Tullibee's 2,500-SHP plant. A slow-turning electric motor that was large enough did not exist [....] rafted, geared turbines were formally chosen in April 1957 as the lightest, most compact arrangement -- and also requiring the least additional development (p.142)
Admiral Rickover disliked rafted geared turbines; at best they were a brute force solution to the gear noise problem. At worst that solution could fail because of some minor imperfection. In 1964, OpNav made one of its periodic attempts to obtain a less expensive SSN. Tullibee had been far too expensive for mass production, but she was also much less expensive than a production Sturgeon. OpNav asked whether a somewhat more capable version could be produced.
Rickover saw the request as a chance to reopen the silencing question. He began work on a turboelectric version of the Sturgeon powerplant. Tullibee's big DC motor would be simply scaled up by a factor of six. A big AC motor would have been much smaller and would have presented fewer design problems, but DC was conceptually simpler. A submarine so powered could easily back down by reversing polarity. That might be rather important for her safety in an unintended dive. Too, a big DC motor could be run very quietly off the submarine's battery, with the reactor turned off altogether. To do this with an AC motor and turbogenerator would require extra equipment, such as an inverter to turn AC current into DC and vice versa. Rickover personally rejected this complication.
As it turned out, the theoretical simplicity of the DC plant masked some terrible practical problems, such as the sheer size of the bus bars needed to carry its current. Quite soon, it also became clear that the DC turbo-electric plant would be massive; the submarine would have to be considerably larger than a standard Sturgeon. Some in BuShips tried to hold down the size by offering an S3W-powered turbo-electric submarine. Rickover rejected it.
[....] The turbo-electric drive submarine (TEDS) was tentatively included in the FY 67 budget, but OSD rejected it as too expensive and unsuited for series production. Rickover objected vigorously. He justified TEDS as a test bed for future silencing techniques on the ground that eliminating the loudest source of noise altogether (gear whine) would make it much easier to test for other sources. After a brutal fight, a TEDS, Glenard P. Lipscomb (SSN-685) was included in the FY 68 budget. The extent to which she was conceived as a straightforward machinery replacement in a Sturgeon hull shows in the fact that she was not allocated a separate SCB number during her design phase. The TEDS did not turn out particularly well. The turbo-electric machinery was unreliable and inherently less efficient than geared turbines. Because she was also considerably larger than Sturgeon, Lipscomb was also much slower. She operated very little after Rickover retired in 1981 and was stricken in 1989 after only 15 years of service. The TEDS fight did make OSD more wary of attacking Admiral Rickover; as a result, TEDS deeply influenced the later decision in favor of Los Angeles (pp. 147-149).
