WordNet
n. game played mainly on board ocean liners; players toss a ring back and form over a net that is stretched across a small court
Wikipedia
Deck tennis is a sport that was played on the decks of passenger and cruise ships and is still practiced to a small extent. The sport is a hybrid between tennis and quoits, and is played with either the rubber disk or ring, or a similarly-sized rope ring. The sport has been standardized and formalized in several countries under names such as " tennikoit" or "ring tennis".
American sources from the 1930s and 1940s attribute the origin, or at least formal establishment of the game, to Cleve F. Shaffer.
Usage examples of "deck tennis".
Having plunged they sported like water babies in the swimming pool or frolicked at deck tennis and as each day passed, and the ship steamed slowly south into equatorial waters, their passion grew inarticulately.