I had a similar problem with my Hobie 18. 2 could easily move it on beach wheels, one... not so much. Especially up the grade. So, I made a portable beach winch
with an ATV electric winch
(with remote), a battery, and a 4x4 post that I anchored at the top of the beach. It had about 100' feet of cable so I sometimes had to relocate the winch
if the distance was less than 100'. Worked like a charm.