Fifty in high wind on the ship (7)
I believe the answer is:
galleon
'ship' is the definition.
(type of ship)
'fifty in high wind on' is the wordplay.
'fifty' becomes 'l' (Roman numeral).
'in' means one lot of letters goes inside another.
'high wind' becomes 'gale' (I've seen this in another clue).
'l' placed inside 'gale' is 'galle'.
'galle'+'on'='GALLEON'
'the' acts as a link.
(Other definitions for galleon that I've seen before include "Large old square-rigged sailing ship" , "All gone (anag.)" , "Historical warship with three or more masts" , "Old Spanish ship" , "Large old sailing vessel" .)