I'm buying out a partner and selling his half to another partner. I already bought out my original partner and he signed a generic bill of sale for his 50% to me that was not notarized. I have to update the coast guard documentation to take him off and add my new partners. The coast guard said I would need to send them a notarized bill of sale from him to me and another one from me to my new partners. I started to wonder if we're going to have to pay sales tax on both of these transactions. I can't seem to find a good answer from anyone. I've already paid the full sales tax on the boat. If this does trigger a new sales tax, should I just get my old partner to sign and notarize a new bill of sale directly from him to the new partners? I really don't want anyone of us to have pay sales tax again. Please advise.

This is probably going to be different depending on which state you're in. For my state, Texas, here is what the comptroller has to say:

"Boat and Boat Motor Sales and Use Tax
The boat and boat motor sales and use tax applies to the purchase of a boat that is 65 feet or less in length measured from the tip of the bow in a straight line to the stern.

This includes:

motorboats
sailboats
jet skis and other motorized personal watercraft
Boat motors subject to boat and boat motor sales and use tax include:

outboard motors (gasoline or diesel)
electric motors attached to a boat subject to boat tax and sold with the boat for one price, such as trolling motors
The boat and boat motor sales and use tax rate is 6.25 percent. The tax is based on the sale price less any allowance for the trade-in of another boat or boat motor.

Permitted dealers collect the tax at the time of sale and remit it to the Texas Parks and Wildlife Department. If the seller does not collect the tax, the buyer must pay the tax when obtaining the boat’s title and registration from the Texas Parks and Wildlife Department or participating County Tax Assessor-Collector’s Office."

https://comptroller.texa...Collector's%20Office .