Thanks for the response and I actually tried using H.sie's V16B1 realism mod which has the 4GB patch in it.
After that it worked but what i did noticed that the merchants did not had correct names and nationalities.
For example I sank a M14X boat with a Dutch flag painted on the hull simply because I saw it was doing evasive maneuvres when i was submerged.
Shot it with the deckgun and saw that it was a enemy unit.
The name is not supposed to be M14x neither.
Then when i closed SH3 and restarted it i had CTD's constantly.
Now im wondering wether or not it's MFM acting up or H.sie's patch that is making it happen.
But the 4GB patch definately helped (for a while)