For me, the games' prolonged bad weather problems relate to crash issues on my PC.
From observations, what I believe is happening is for example, chasing a convoy in horrendous waves and rain causes small ships of the convoy to sink or start sinking, and/or they all just start making zig-zag patterns like a convoy is under attack, but they still keep their same heading for tens of kilometers before eventually straightening formation.
It is nearly is impossible to attack in this scenario and going to periscope depth has caused my game to -crash, more than a few times.
Also, as I've happened upon lone mercs in high seas/waves/rain, down by the bows like it's sinking, but still making progress, as our boat plows into big waves burrowing under 10 meters depth, I get another game crash.
In another thread, (can't remember where) fellows talk of the game save issue of never saving while at periscope depth when a ship nearby is, or may be, sinking. Seems these two problems are related, in my estimate.
Prolonged bad game-weather makes me head south toward the Equator and forget attacking anything in those big squalls.
