[Silent Steel]

Originally Posted by GeneralLawson

My game crashes to desktop within the first 20 minutes or so every time I start the game, but then it won't crash again for the rest of the time I play it.

Ahoy general & WELCOME to the forum. Looking forward to hear more from you.

Here are some suggestions + I've done a few changes in your list.

Open Horizons II full 1.4 => Try the 'Base' version instead. As the 'Full' version is heavy on your CPU maybe that's why you get those CTDs.
FX Update 0.0.19
New UIs TDC 6.8.0
New UIs TDC 6.8.0 Patch 1 => Please tell how you applied this mod. With the Migrator app?
IRAI 0.0.30
20% Mines ice dolphines v2
50% reduced port ships from OHII full
Remove mines-ice-dolphines from OHII full
Dynamic Environment=> Try this, you won't be disappointed
Nauticalwolf's Interior Mod 1.0 => Try this Steel Viking's Interior Mod - don't forget the patch
Trevally Automated Scripts 0.6
Trevally Harbour and Kiel Canal Pilot 2.8
Accurate German Flags
MightyFine Crw Mod 1.2.1 Alt w Beards
German U Boat Crew Language Pack
Stormys DBSM SH5 1.3 Basemod