| Term | Definition |
|---|---|
| floor keelson | Timbers bolted to the floors and running parallel to the main keelson. |
| keel | A steel beam or timber, or a series of steel beams and plates or timbers joined together, extending along the center of the bottom of a ship from stem to stern and often projecting below the bottom, to which the frames and hull plating are attached. |
| keelson | A structure of timbers or steel beams that are bolted to the top of a keel to increase its strength. Also spelled kelson. |