High TC can certainly
seem to cause problems with weather, but smarter people who understand the nuts and bolts of the program swear it doesn't.
Personally, I do not quite buy it either, but that's what they say...
And it can certainly screw up your day if you run across a destroyer in moderate visibility. At 256TC, 1 second of real time = over 4 minutes of game time that you may or may not lose depending on the skill of your watch crew.
One trick, if you simply must cross some water at higher TC, is to set SHIII Commander to automatically set TC to 0 when a plane or ship is spotted. But since TC goes to 0 then whenever a ship is detected, it can be quite frustrating when waiting for a convoy to approach underwater.... every time your sonar team reacquires a target, the game stops.