Ship catching halibut originally coming in earlier (8)
I believe the answer is:
schooner
'ship' is the definition.
(I've seen this before)
'catching halibut originally coming in earlier' is the wordplay.
'originally' indicates taking the first letters.
'coming in' means one lot of letters goes inside another.
'earlier' becomes 'sooner' (synonyms).
The initial letters of 'catching halibut' is 'ch'.
'ch' put within 'sooner' is 'SCHOONER'.
(Other definitions for schooner that I've seen before include "Two-master; a glass" , "Two-masted sailing ship" , "In the main it is" , "Old sailing vessel and large glass" , "Measure for sherry or kind of sailing ship" .)