Small boat that's easily damaged (6)
I believe the answer is:
tender
This clue is a double definition.
'small boat' is the first definition.
(type of small boat)
'easily damaged' is the second definition.
(I've seen this before)
'that's' acts as a link.
(Other definitions for tender that I've seen before include "'Soft, sensitive offer? (6)'" , "Gentle and sore" , "Ancillary vehicle" , "Offer, gentle, boat" , "Affectionate - easily hurt" .)