Boat and trailer left behind by previous owner

[Traci Lovelace]

Just closed on a house in our neighborhood to renovate and sell.  Its waterfront, that is the big appeal. It was formerly owned by a hoarder and the basement, attic and garage are full of junk.  In addition, there's an abandoned john boat with a motor, and a separate large trailer for a substantial boat on the lot.  It has permanent trailer tags.

The seller was supposed to clear all personal property out prior to closing and we delayed for a week in order for them to do so.  However, they failed to take any action.  We got some cash back at closing instead, and a signed addendum that stated all personal property transferred to us at the time of sale.

My junk guy is going to do a cleanout, but we are thinking of selling the boat and trailer.  What do we need to do to get title? Anybody?