The difference between SH4 and 5 is that in 5 many of the ships use more than one texture for the diffuse maps.
Those can be found in SilentHunter5\data\Textures\TNormal\tex
For example, Black Swan Sloops uses the following textures:
- ship_T02.dds
- ship_N02.dds
- ship_hull_T02.dds
- ship_hull_N02.dds
Beware! Some of them are shared between multiple ships, which means changing it for one ship changes it for the others too. Normally you wouldn't need to do it, can change just the Ambient occlusion texture as we did for many ships in the game.
If you really must, make a copy of each texture you need to modify and add a suffix to it - for example
- ship_T02blue.dds
- ship_N02blue.dds
Then all you need to do is add the following in the roster file:
[Texture 2]
TextureName=*blue.dds
Check Northampton, Brooklyn and the AMC version of Rawalpindi for reference.