More than likely a 28-29' boat will be a lot more weight than you're rated to tow. Your MH is probably rated to tow 3,500-5000#. I tow a boat and trailer that weigh over 6,000# with a a 97 24' V10 powered MH. The hitch that was on the MH when I bought it was rated for 3,500# and was what Coachmen rated the MH to tow. I pulled off that hitch and had a welding shop custom make a new hitch, which ties into the main chassis frame. As far as I'm concerned I'm now good for the full GCWR of the Ford van.
Have never had any problems towing or launching/retrieving.