The Type=XX lines in the config files between "Data / Roster / Country / Sea / Ship.cfg" and "Data / Sea / Ship / Ship.cfg" have to match (as do all of the other category config files).
If you open the Museum and select "Japan", does it crash immediately, or do you see the Yamato? If you don't see it, it's supposed to be set to a Type=20 in most mods and stock. If you see the Yamato, but not the next BB, then that next one has issues, and so on down the line. If you can see the Yamato but it crashes on the next BB, use the drop-down boxes to select a different class and see what you get. Once you can get through the Museum without issues, you can generally get through the game. Double-check your spelling. SH4 does not like typos at all...
Another course of action would be to run
SH Validator on the install - in fact, you should do that first - see if you get Class= errors or some such. It does not catch all errors (it doesn't look into the binary files), but it does get you a good idea of where you stand. If you want, post the errors found in the log file, if you don't understand any. You'll most likely get a few "Out of sequence" errors and such, as well as either Class= and / or Type= errors. Also, check all of the dates (don't overlap them except in certain situations).
Someone with more experience probably has pointers that might be more efficient at getting you going.
