The Keel is the backbone of the majority of ships and boats. It runs longitudinally along the bottom of the boat, in the center of the hull from stem to stern. Depending on the vessel it will be made of metal or timber or another robust and rigid material. It gives a boat greater control and stability when moving forward.
A Knot is a unit of speed used in marine navigation. It is defined as one nautical mile per hour. A nautical mile is a little over a standard mile. One nautical mile = 1.15 miles = 1.85 kilometers. One knot = 1.15 miles per hour = 1.85 kilometers per hour.