The Skaven ships in Man O' War are just as unpredictable as the army is
in Warhammer. The warpblast can be defistating but most of the Warpraiders
end up in smoking wrecks by the end of the game. Hopefully you've taken lots
of the enemy with you. Again the spells are very powerful and we tend  not to
use magic all that often in our games because sometimes it can really unbalance the results.