It's a Bill of Sale, not a receipt
This is the form I used when I sold my last boat (and previous boats too). There was no mortgage on the boat:
Date:___________________
"Margaret W. Hall , of 5319 Littlebrooke Court, Dunwoody, Georgia 30338 (“Seller”) hereby agrees to sell to Melvin W. Meeks of 5102 Dunwoody Gables Drive, Dunwoody, Georgia 30338 (“Purchaser”) a boat known as a 1980 Trojan F32, HIN TRJ001170879 (“Boat”), for the sum of $48,000.00 (Forty-eight thousand dollars and no cents). Additionally, Purchaser agrees to pay 50% of the 2001 ad valorem tax when due.
"Seller warrants that there are no liens or other encumbrances against the Boat.
"It is understood that the Buyer purchases the Boat, including engines, generator and all other systems and included equipment “as is,” not subject to any conditions whatever, and that the Seller does not issue any other warranty, expressed or implied."
Signed by both seller and Purchaser and witnessed.
Mine was a twin engine power boat. Since yours is a sailboat you'd change it to include sails engine, maybe rigging...I dunno. The important thing is that you include your name, the buyer's name and the boat's HIN and state that the buyer is buying "as is" with no warranty expressed or implied.