The Writings of Abraham Lincoln, Volume 2 by Abraham Lincoln
Request for a Patent
IMPROVED METHOD OF LIFTING VESSELS OVER SHOALS.
Application for Patent:
What I claim as my invention, and desire to secure by letters patent, is the combination of expansible buoyant chambers placed at the sides of a vessel with the main shaft or shafts by means of the sliding spars, which pass down through the buoyant chambers and are made fast to their bottoms and the series of ropes and pulleys or their equivalents in such a manner that by turning the main shaft or shafts in one direction the buoyant chambers will be forced downward into the water, and at the same time expanded and filled with air for buoying up the vessel by the displacement of water, and by turning the shafts in an opposite direction the buoyant chambers will be contracted into a small space and secured against injury.