Usage examples "keel":
These people are wonderfully expert, remaining under the surface nearly two minutes; and the water in the harbor of Nassau is so clear that they can be distinctly seen even at the keel
of a vessel. - "The Narrative of a Blockade-Runner",
The skeleton and the keel
are made of very thin deal planks, fastened together with the sinews of the whale, and covered with the skin of the sea- horse cleared of the hair. - "A New Voyage Round the World, in the years 1823, 24, 25, and 26, Vol. 2",
Otto von Kotzebue.
They crossed the clearing and boarded the keel
boat which rested against the bank. - "The Prodigal Judge",