Rescue craft (8)
I believe the answer is:
lifeboat
'rescue craft' is the definition.
(I know that lifeboat is a type of sea rescue vessel)
This is all the clue.
(Other definitions for lifeboat that I've seen before include "It's used to rescue people at sea" , "I bet loaf on maritime rescue vessel" , "Sea rescue craft" , "It carries out rescues at sea, and is carried aboard large ships" , "Rescuer" .)