[TorpX]

Originally Posted by Sailor Steve

Maybe you should fill in the blanks for me. The tachometer is no more accurate for measuring ship speed than the pitot tube is for measuring aircraft speed. There were P-47 pilots who claimed they broke the sound barrier in a dive. That's how 'accurate' they are. A shipboard tachometer doesn't have direct contact to the surface medium like a car's does. It can't account for propellor slippage or cavitation.

I'm not saying it didn't happen. What I'm saying is that I have 35 years experience playing tabletop wargames with 'gamers' who want every advantage, and their justification is always the same: "I read it in a book somewhere".

I've read the same thing that Eric did. I believe it was in O'Kane's CLEAR THE BRIDGE. His claims would be based on the speed incicated by the Bendix log. I don't know what you refer to when you use the term tachometer. While the Bendix log would not be as accurate as a timed trial, great care was taken to calibrate it for accurate results. If it had not been accurate, the firing solutions genarated by the TDC, would not have been sound.

Did any timed trials ever get a Gato past the claimed 20.25 knots?

Perhaps not, but there are more variables here in a Gato or any sub, than with a battleship. Current displacement, and charge on the battery would affect this. Do timed trials usually involve pushing engines beyond their design limits?

Of course you are free to accept whatever sources you choose, but I am inclined to take O'Kane's word for it, as he has spent more time in fleetboats than I.