. . . As 2010 is the International Maritime Organization’s Year of the Seafarer the theme chosen gives people a chance to read and think about exploring the undercurrents in the Numenorean romance the “Tale of Aldarion and Erendis” from “Unfinished Tales”, the journeys and ships of the Teleri, the flight of the Noldor, and the voyages of Tuor and Earendil in “The Silmarillion”, or Bilbo’s poem about the latter in LotR. There are also the poems “The Happy Mariners” and at a pinch “Bombadil Goes Boating.”
I'd go with "The Sea-Bell", myself. Or perhaps "AElfwine of England (from The Book of Lost Tales, part II). I don't suppose there's anyone out there who, finding "The Mariner's Wife" too cheery, wd give "The White Ark" (from A Secret Vice) a try?