A pole with a hook at the end.

1

1850.  Richard, armed with a picaroon, descended the slip, some thirty feet, to the basin, where the logs lay in the water ready to be drawn in, and by aid of the tooth of the mill-chain dog, to be hauled to the bed of the mill.—S. Judd, ‘Richard Edney,’ p. 42.

2

1850.  The Boy made his picaroon fast to his boat with a rope.—Id., p. 220.

3