[CapnScurvy]

As propbeanie stated, a lot of issues come from not having the same "UnitType"; "ClassName" found in the units "Roster" .cfg file:

[UnitClass]
ClassName=BBColorado
UnitType=11
AppearanceDate=19210721
DisappearanceDate=19470107
DisplayName=US BB Colorado

Compared to the corosponding units "Sea" .cfg file:

[Unit]
ClassName=BBColorado
3DModelFileName=data/Sea/NBB_Colorado/NBB_Colorado
UnitType=11
MaxSpeed=21
Length=190.2
Width=30.2
Mast=42.2
Draft=9.1
Displacement=32600
RenownAwarded=1500
CrewComplement=400
SurvivalRate=90
SurvivalPercentage=20

They have to be the same!!

If by opening up the Museum, you can at least get to the first displayable unit, then here's how to narrow down the culprit that's giving you a CTD.

If you know the trouble is in the Japan section, and it seems like it's just after looking at one of the Battleships, try to remember which one it was? Mouse over the top center console, use the top most "Nationality" field to go to the Japan group. Make sure you have "All" listed, then open the lower "List". This list of ships is in the exact "order" of appearance the ships will be in if you use the arrows to go through them. Try to find the last good ship you remember being displayed and write down the units that are displayed after that unit. With at least a half dozen written down, in their order of appearance, start going back down through the list in the Museum displaying them. When you find the CTD one, you know its just after the last good unit that was displayed on your list. There's you problem unit.

You may have more, so it's always good to fix one, then test things again.