So, it appears, that something is wrong with Hull1.msh
Maybe you have isolated vertices? Vertices which are not part of a polygon.
Can you post Hull1.msh so we can take a look. Paste contents as code
..insert here..
To test. Assume that the other meshes are ok.
Rename Hull1.msh to Hull1.bak
Copy Hull2.msh and rename to Hull1.msh , then try reloading the model in the game.
If it works then the ship will appear, with a missing bow, and we will know that Hull1.msh must be fixed.
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I see that you appear to have gone straight to exporting the full model.
Small errors are common with most of my projects and require to be debugged.
I usually start just by exporting the LOD0 Hull and check that it is ok in the game before adding more parts.
Then add the other parts a few at a time.
When the LOD0 model is complete and working, then I will add the other LODs etc.
This makes it easier to identify bugs.