The Collaborative International Dictionary of English v.0.48:
Shipboard \Ship"board`\, n. [Ship + board. See Board, n., 8] A ship's side; hence, by extension, a ship; -- found chiefly in adverbial phrases; as, on shipboard; a shipboard. [1913 Webster]WordNet (r) 3.0 (2006):
shipboard adj 1: casual or ephemeral as if taking place on board a ship; "shipboard romances"