Swell accommodation? (3,4)
I believe the answer is:
sea legs
I'm afraid I can't even guess how this answer relates to the clue.
Can you help me to learn more?
(Other definitions for sea legs that I've seen before include "Balance on board" , "not to feel sick on board?" , "What a good sailor has" , "Ability to maintain one's balance on a ship" , "resistance to sickness" .)