Couple involved in canasta aboard ship? (5)
I believe the answer is:
decks
If this is the answer I cannot explain how the clue works.
Can you help me to learn more?
(Other definitions for decks that I've seen before include "Platforms on a vessel" , "Embellishes" , "Packs of playing cards" , "Sets of cards" , "Packs of cards (US)" .)