I too would like to request this, if someone is able to decipher it.

I am also interested in moding SH3. So here is what I know.... As far as *.dat files there is already unpacker available. You can find it at http://www.subsim.com in SH3 modding section. Or send me PM and I ll share it with you. It requires Java though. Now as far as two other files *.sim and *.zon...

Oh not sure if this is within the scope of what you do, but there are also 2 other files important to the modding of this game. .sim and .zon, which we currently have no option but to hex edit only.

I was wondering if you could add support for Silent Hunter 3 .dat.

I cant vouch for the demo, but pre patch 17 files are actually already able to be extracted. Everything past 17 isnt.

Yes textures are .dds