Sea bed? (7)
(Other definitions for hammock that I've seen before include "Hanging cloth bed" , "Bed tied between trees?B" , "String bed" , "A suspended canvas or rope bed" , "Hanging bed of canvas or rope" .)
'sea bed?' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for berth that I've seen before include "Bed on a ship/train" , "Bed for traveller" , "Bunk; mooring place" , "Bunk on ship or train" , "Place to sleep on a ship" .)