Island cheers beginning of sailing craze (8)
I believe the answer is:
tasmania
'island' is the definition.
(I know that Tasmania is a island)
'cheers beginning of sailing craze' is the wordplay.
'cheers' becomes 'ta' (both can mean thank you).
'beginning of' suggests taking the first letters.
'craze' becomes 'mania' (I've seen this in another clue).
The first letter of 'sailing' is 's'.
'ta'+'s'+'mania'='TASMANIA'
(Other definitions for tasmania that I've seen before include "State off 23 [VICTORIA]" , "What a relief!" , "somewhere in Antipodes?" , "Asian ATM in Australian federation" , "Commonwealth state" .)