the support sailors always level up slower than the arm sailors/gunners make sure
you leave them on all the time its better to have good sailors and less armour! than
all armour and crap sailors. makes it much better especially once you get higher.

Have them "equipped" and play lots of games. Thats the way to lvl them.

Also check out trainworld and look for the xp%/lvl chart that explains what type of
ship gives the most % of xp to each range of lvl.