GO to the LDWF office in Lake Charles. Get a registration transfer document and fill it out.
Keep one of the pages for your temp. registration and mail in the other one along with the sellers registration that is signed on the back by the seller.
That should take care of the boat.
You will need a trailer title signed by the seller along with the registration. Bring that to the dreaded place you get your drivers license and they will take care of that part for you. This will take care of the title and registration for the trailer.
In La., you don't pay taxes on a boat older than 10 years old.
If you buy new from a dealer, they normally take care of everything. When new, you have 3 places to send paperwork to.
http://www.wlf.louisiana.gov/boating/bo ... gistration