Keelson

n.

1.

(Shipbuilding) A piece of timber in a ship laid on the middle of the floor timbers over the keel, and binding the floor timbers to the keel; in iron vessels, a structure of plates, situated like the keelson of a timber ship. Cross keelson a similar structure lying athwart the main keelson, to support the engines and boilers.

Noun

1.

keelson - a longitudinal beam connected to the keel of ship to strengthen it

beam, hull