Another option you may consider is to play multiple careers-each in a different flotilla.
That way, you get a variety of boats, areas to patrol, etc.
I currently have five careers going. When I get retired(via SH3Commander) or die

, I move on to one of my other careers and cycle thru flotillas like that.
If you don't have it yet, get SH3Commander. It adds to the immersion and makes multiple careers a snap. You can change your assigned patrol grid as well with it.
Like people have said, get GWX or one of the other super mods. It is well worth it.