A boat rowed by one man with a light kind of oar, called a scull; also a one-horse chaise or buggy.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Scull * Scull ThatcherNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes