Select raft to carry mythological princess (7)
I believe the answer is:
electra
'mythological princess' is the definition.
(I've seen this before)
'select raft to carry' is the wordplay.
'to carry' indicates the answer is hidden within the clue (I've seen 'carrying' mean this).
'ELECTRA' is hidden in the letters of 'select raft'.
(Other definitions for electra that I've seen before include "complex character" , "type of complex" , "Female avenger" , "Tragic daughter of Agamemnon" , "It's a kind of complex" .)