JamesI is right... The ship should be like 10 levels ahead of your crew or close to that.
Having more than that will give you a crappy exp since the bigger gap between lvl of ship
and lvl of your crew, the lesser exp you will get. But it really depends on your
performance in battles, play your ships the right way (KM style) and get some good attacks
and youll be fine.

good hunting.

Use the search function. For advice typically look in tip and tactics:
http://www.navyfield.com/board/view.asp?
Num=43764&Sort=D07&Order=re_upday&PageSize=20&Page=1&SearchPart=title&S
earchText=experience&Ctg_1=&Ctg_2=&Ctg_3=

I.E. go with the ship that is closer to the level of your sailors. Also, note, the bigger
the ship, the better the experience.

A ship within + or - ten levels of your sailors levels