Go over front of ship, finding a weapon (8)
I believe the answer is:
crossbow
'a weapon' is the definition.
(crossbow is a kind of weapon)
'go over front of ship' is the wordplay.
'go over' becomes 'cross'.
'front of ship' becomes 'bow' (I've seen this before).
'cross'+'bow'='CROSSBOW'
'finding' is the link.
(Other definitions for crossbow that I've seen before include "Weapon firing bolts" , "historic weapon" , "Old weapon of war" , "Weapon (used to set off a quarrel?)" , "Medieval weapon" .)