I use a winch system with my hartley trailer which I made myself.
Basically mounted a winch bought on ebay for about a tenner with 2 bolts onto a piece of 1 inch box tubing cut to about 12 inches.
Tie a sheet around the mast upto the bow for the winch cable (or better still a belt) hook to pull from.
Job done.
The mast support tube (with the 2 reinforcements) is well up to standing the forces required to pull a wayfarer out of the water with the launching trolley.
When I want to use the road trailer on road, I can remove the winch and pop in the mast support tube and vice-versa.