Scot heading for rope in bottom of boat and fish (8)
I believe the answer is:
mackerel
'fish' is the definition.
(mackerel is a kind of fish)
'scot heading for rope in bottom of boat' is the wordplay.
'scot' becomes 'mac' (many Scottish surnames begin with Mac).
'heading for' indicates taking the first letters.
'in' is an insertion indicator.
'bottom of boat' becomes 'keel' (I've seen this before).
The first letter of 'rope' is 'r'.
'r' inserted within 'keel' is 'kerel'.
'mac'+'kerel'='MACKEREL'
'and' is the link.
(Other definitions for mackerel that I've seen before include "that's fishy" , "Banded food fish" , "Sea fish" , "Marine food-fish" , "Fish caught by spinner (or sprat?)" .)