Wiktionary
sneakbox
n. A small boat that can be sailed, rowed, poled or sculled, predominantly associated with (w: Barnegat Bay) in New Jersey.
Wikipedia
Sneakbox
A sneakbox is a small boat that can be sailed, rowed, poled or sculled. It is predominantly associated with the Barnegat Bay in New Jersey, just as the canoe-like Delaware Ducker is associated with the New Jersey marshes along the Delaware River near Philadelphia.
Railbird skiffs and garvey-like sneakboxes are other American hunting-boat types. Typically, they were all used for hunting waterfowl and marsh birds but also have been used by trappers.