
• (n. pl.) Raised pieces of wood of iron around a hatchway, skylight, or other opening in the deck, to prevent water from running bellow; esp. the fore-and-aft pieces of a hatchway frame as distinguished from the transverse head ledges.
Found on
http://thinkexist.com/dictionary/meaning/coamings/
Coam'ings noun plural [ Confer
Comb a crest.]
(Nautical) Raised pieces of wood of iron around a hatchway, skylight, or other opening in the deck, to prevent water from running bellow; esp. the fore-and-aft pieces of a hatchway frame as distinguished from the transverse head ledges. [ Written...
Found on
http://www.encyclo.co.uk/webster/C/99

On a ship, coamings are raised frames rather higher than the deck, about the edges of the hatch-openings, to prevent the water on deck from running down.
Found on
http://www.probertencyclopaedia.com/browse/RCA.HTM
No exact match found.