Hat Money Publique Deposited
According to Wharton, Law Lexicon, 1864, this was "a small duty paid to the captain and mariners of a ship, also called primage."
The custom appears to have been in force in the seventeenth century, for C. Molloy, in a work De Jure Maritimo, 1676 (ii. 9, 6), says: "Petty Averidge is another small Duty which Merchants pay to the Master.... The French Ships commonl term the Gratuity Hat-money."
- Frey's Dictionary (American Journal of Numismatics, Vol. 50, 1916)