
1) Beam 2) Ship-strengthening timber
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https://www.crosswordclues.com/clue/keelson

lengthwise wooden or steel beam in ship for bearing stress
Found on
http://phrontistery.info/k.html

lengthwise wooden or steel beam in ship for bearing stress
Found on
http://phrontistery.info/nautical.html

Timber(s) bolted on top of the keel, or the frames above the keel, to reinforce it.
Found on
http://shipwrightjournal.blogspot.co.uk/p/glossary-of-nautical-terms.html

• (n.) 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.
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http://thinkexist.com/dictionary/meaning/keelson/

A beam attached to the keel on a wooden boat to add strength.
Found on
http://www.diy-wood-boat.com/Boating-terms.html
Keel'son noun [ Akin to Swedish
kölsvin , Danish
kjölsviin , German
kielschwein ; apparently compounded of the words
keel and
swine ; but confer Norweg.
kjölsvill , where
svill is akin to English
sill ,
noun ]
(S...Found on
http://www.encyclo.co.uk/webster/K/4

In wooden shipbuilding, a keelson is 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.
Found on
http://www.probertencyclopaedia.com/browse/RK.HTM

A structural member above and parallel to the keel.
Found on
http://www.sailinglinks.com/glossary.htm

[
n] - a longitudinal beam connected to the keel of ship to strengthen it
Found on
http://www.webdictionary.co.uk/definition.php?query=keelson
[Treasure Island] a longitudinal beam or set of timbers fastened inside the hull of a ship along the keel to add structural strength.
Found on
https://www.cliffsnotes.com/literature/t/treasure-island/study-help/full-gl
noun a longitudinal beam connected to the keel of ship to strengthen it
Found on
https://www.encyclo.co.uk/local/20974

any of various fore-and-aft structural members lying above or parallel to the keel in the bottom of a hull.
Found on
https://www.infoplease.com/dictionary/keelson
No exact match found.