Let's say a friend has a stalled restoration project. Let's also say that this particular project is an old Chris Craft cruiser on blocks. Is there a way to temporarily convert a tandem axle car trailer to boat trailer for a 50 mile tow?
My google skills turn up all kinds of examples that go the other way.
Wood deck car trailer? Depending on how deep the V is you can mount 2x10s on edge to act as hull supports. A lot of the modern saltwater trailers use that setup. Cover the tops with carpet scraps to protect the hull. Strap the boat down well and drive slow.
Build something like this?

I would just call a boat mover and save myself a lot of work and stress.
Paul
I converted my HF 4x8 trailer to haul a 14' boat. It was as easy as screwing some 2x6s to the deck.
Of course, that was a 500 lb hull, but it worked for 20 years.
If the hull is solid, just get it on the trailer and stuff some blocking under the hull with a piece of carpet on it.