[Snarf]

I've just finished reading Wahoo and Clear the Bridge! also. An interesting tidbit with the screw count for knowing the enemy's speed. On Tang, they ended up bringing aboard a metronome. The sound man would match the metronome to the ships screws, and he could instantly tell if the ship was speeding up or slowing down before you would ever be able to tell by ear.

O'Kane had a bit of frustration with the Mk 18 torpedoes too (a bit of an understatement since one sunk Tang). Before the war torpedoes were made at one place and they were handcrafted, even though they had exploder and depth keeping problems, the rest of the torpedo functioned quite well. During the war, they had many contractors who bid bottom dollar to make the Mk 18's so the build quality really left a lot to be desired. O'Kane talks about this in Clear the Bridge!, after their problems getting hits with the Mk 18's he had his torpedomen take apart and test everything and fine tune the torpedos, and then he started getting hits with them. His last patrol, the whole lot were Mk 18's taken aboard from Tambor (as they were experiencing shortages at the time). Once again he had his men make sure the torpedoes were functioning in top shape, and they scored hits with nearly all of their torpedoes, save the last fateful circular run.

Regarding speed again, O'Kane said they were doing 22 knots when they were picking up downed aviators off Truk. I wonder now on the performance difference between the F-M and the GM Vinton engines, as Tang had F-M engines and Barb had GM Vinton's. From what I've read, Barb seems to have the speed record.

Another interesting thing, O'Kane mentioned using the turbos (the air compressors for the ballast tanks) to blow air out the bottom of the ballast tanks to keep the sub as high out of the water as possible with the added effect of creating a layer of air bubbles under the sub which reduced drag, and it made a difference of a knot or two.