What is a centimeter?
A centimeter (cm) is one hundredth of a meter and just under four tenths of an inch (0.3937 inches). The prefix comes from the Latin centum, a hundred.
Divide centimeters by 30.48 to get feet, or multiply feet by 30.48 to get centimeters. The factor is exact, as a foot is 30.48cm, and a single centimeter is about 0.0328 feet.
The centimeter was the base unit of length in the CGS (centimeter, gram, second) system that physicists used before SI, which is why older physics talks about dynes and ergs.
What is a UK nautical league?
A UK nautical league is three UK nautical miles, ie 18,240 feet or 5,559.552 meters, which rounds to 5.56 kilometers. The international nautical league is slightly shorter at 5,556 meters.
Don't confuse it with the land league, which is three statute miles. The nautical league is three nautical miles, about 3.45 statute miles, so it's roughly 15% longer.
Britain's territorial waters once reached one marine league – three nautical miles – from the coast. The limit has been 12 nautical miles, or four leagues, since 1987.