Bed in a ship for a girl (6)
I believe the answer is:
bertha
'girl' is the definition.
'bed in a ship' is the wordplay.
I cannot quite understand how this works, but
'bed' could be 'berth' (berth is a kind of bed) and 'berth' is found in the answer.
'a' is found in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
'for a' is the link.
Can you help me to learn more?
(Other definitions for bertha that I've seen before include "big woman?" , "Big ..., heavy German howitzer in World War 1" , "43-ton German howitzer, Big _____" , "Breath (anag) - girl's name" , "Female name; Big -, World War one German howitzer" .)