baggywrinkle
/ˈbæɡɪwɹɪŋkəl/Definitions
1. noun
A type of marine growth, particularly a type of seaweed or barnacle that forms a wrinkle-like growth on the hull of a ship or boat.
“The old sailing ship had a thick layer of baggywrinkle on its hull, which made it difficult to navigate through the harbor.”