This is a screenshot of the start screen:
Notice on the right side, the third line - once you have selected your name and flotilla, then the available types will show up. Select one and the appropriate boat numbers will be in a drop-down menu. Or just type in whatever you want IF it is not listed - but the ones in the menu are the ones available in your year.
p.s. Notice I have a crew selection that matches my boat - one of the functions that you can add in SH3Cmdr!