Definition of keelson in US English:


(also kelson)


  • A centerline structure running the length of a ship and fastening the transverse members of the floor to the keel below.

    • ‘The ribs would have been treated with steam so that they could be bent sharply over the keelson.’
    • ‘When we found she could sail in stronger winds, we fitted a stronger mast and rigging and, later, a keelson, an internal timber spanning three frames.’
    • ‘One of the main uses we have made of it is for the keelson which required a piece of wood 6.7m in length.’
    • ‘There was no central keel in the hull, but a large extruded central keelson was used.’
    • ‘‘A few short ribs at the bow and stern will be fitted later when the new keelson is in place,’ said John Steer, one of the committee members.’


Middle English kelswayn, related to Low German kielswīn, from kiel ‘keel of a ship’ + swīn ‘swine’ (used as the name of a timber).