Vessels just about wrecked at Spithead (1-5)
I believe the answer is:
u-boats
'vessels' is the definition.
(U-boat is an example)
'about wrecked at spithead' is the wordplay.
'wrecked' is an anagram indicator.
'at' means one lot of letters go next to another.
'spithead' becomes 's' (head letter of 'spit').
'about' anagrammed gives 'uboat'.
'uboat'+'s'='U-BOATS'
'just' acts as a link.
(Other definitions for u-boats that I've seen before include "Submersible warships" , "German submarines of second World War" , "German submarines in WW2" , "German subs" , "Submersible ships of WW2" .)