Announced they'd holes in their sail off the coast there (6)
I believe the answer is:
islets
'announced they'd holes in their sail off' is the definition.
I can't judge whether this definition defines the answer.
'the coast there' is the wordplay.
I cannot quite understand how this works, but
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is present in the answer.
The remaining letters 'isles' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Another definition for islets that I've seen is " small keys".)