The age of wrecked boats? (5)
I believe the answer is:
sabot
'the age' is the definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.
'wrecked boats?' is the wordplay.
'wrecked' is an anagram indicator.
'boats' is an anagram of 'SABOT'.
'of' acts as a link.
Can you help me to learn more?
(Other definitions for sabot that I've seen before include "Wooden clog" , "This from last" , "Wooden-soled 13 down" , "French clog" , "Boast (anag) - shoe" .)