Not sure about the Steam version of the game but I just completed an SH3 installation using my old DVD version of the game from 2005 and ran into the same issue.
My answer was I forgot to update Silent hunter III FIRST with the game patch to ver 1.4B.
Then I applied the HSIE patch.
Also,, after updating the game to ver 1.4b I had to apply the HSIE before anything else. If you apply the 4gig memory patch prior to HSIE it will not see a correct version of the game.
Here is a link to get that file.
https://www.mediafire.com/file/dvrtf...4b_us.rar/file
Hope this helps.