[Capt. Morgan]

I've noticed that the displayed speed on the status-bar for my own sub is always an integer, while the displayed speed on the dial can show fractions, so I've always assumed that the TDC/status bar is programed to only show the approximate speed.

I always enter my exact calculated speed into the TDC, and my torps. almost always hit the part of the ship I'm aiming at.

(I must say that I do like German targeting computer better though)