Raft I'd lost at sea (6)
I believe the answer is:
adrift
'at sea' is the definition.
(drifting at sea)
'raft i'd lost' is the wordplay.
'lost' indicates anagramming the letters.
'raft'+'id'='raftid'
'raftid' is an anagram of 'ADRIFT'.
(Other definitions for adrift that I've seen before include "Floating uncontrolled" , "without purpose or direction" , "Undirected" , "Aimlessly floating" , "Unanchored - lost" .)