Thanks, i appreciate, JScones.
No, i don't have SH3 Comdr.
While trying to fix this issue today, i was wondering if this line of code (SeaInfName=SeaInf.raw) was part of the solution;
[SeaInfo01]
StartDate=0101
EndDate=1231
SeaInfName=SeaInf.raw
Compressed=NO
...because it's referring to a map that shows the limits of each Seatype with 3 different shades of gray.
Maybe, the game was rushed, and the programmers left this option unfinished...