Re: Pontoon on a lift
You have not said whether the old v hull boat was lifted by a sling or if the boat was sitting on bunks or a rack.
What style lift are you talking about?
My boathouse has an Ace lift, and the boat is held up by 1/4" cables on 4 corners. A 6" nylon sling put a small dent in one of the toons--after 26 years usage. I've spent the last 2 weeks fabricating a 11' x 18' rack (4" channel iron) and my new Bennington's toons are each sitting on two 2X8's mounted flat on the frame.
It all comes down to how much you need to spend. If your boat's very old and not worth much, I'd just put it in slings. My rack cost $600 in parts, and it'd cost $2K+ to have a dock contractor fabricate and transport one by barge/tugboat/crane.