[Muas]

STREL_ALT_SHRT1 is coded in the Hurricane Mk.I hier.him cockpit, and of course in java, so it's needed. With Winmerge you can simple merge it form Hurricane Mk.I hier.him into SeaHurricane hier.him. This should fix the problem.

Yes, the problem is that the file only exists in its SFS container, that means that the complete path to the mesh must be included in the hier.him, as long as it accepts it - something like "3do/cockpit/HurricaneMkI/STREL_ALT_SHRT1.msh".

Working on hier.him delete all the mesh you don't need (for ex. [FONAR], [FONAR_GLASS]) and add the new ones ([FONAR1], [FONAR_GLASS1], [FONAR2], [FONAR_GLASS2], [Arrester1]). In the Hurricane MkI cockpit folder copy the new files you have created for Sea (FONAR1.msh, FONAR_GLASS1.msh, FONAR2.msh, FONAR_GLASS2.msh, Arrester1.msh, PRIBORY3.mat, PRIBORY3.tga ecc. ecc.
I'll give it a look, but it should work fine. Hier.him must be renamed as SeaHurricane1.him for ex. also DOSKA must be renamed if i'm not wrong, for ex. DOSKA2.

You're right, that's the renaming of the new him that I missed. I guess this is the early technique used when first sound mod came out, and new flyables were using existing cockpits.

Somehow I end up with complicated solutions whan all should be kept simple and reliable.
Thanks for the tips.