One of the things I treasure most about studying pirates and their ilk is the rich language they left behind. Sailing has a language all its own and crumster (also crompster or cromster) is an archaic word in that language. A crumster was a type of ship. Specifically, it is a dutch-made coastal vessel whose full name is a cromsteven, which means bent stem, referring to something in its construction, no doubt. A more English name for a crumster is a hoy. From the 16th to the early 19th century, the crumster was one of the most common types of ships sailing the seas.
A crumster was built to be a coastal vessel. They have 2 (or 2½) masts, carry about 60 to 80 men, 12 to 16 cannons, and were often used as armed-merchantmen. They are square-rigged on the fore-mast, spritsail-rigged on the main mast, with either a boom-rig from the main mast or a small lateen-sail at the aft of the ship. These sleek and low-slung ships were favored by buccaneers and Caribbean merchants alike.