How to build your own kayak cart that is lightweight and floats for $25. Purchase plans from this site. Appears to be made of push lawn mower wheels and axel surrounded by a configuration of PVC pipes and elbows. Covered in foam; that looks like a dollar store pool noodle. Add a web strap band to hold kayak to the cart.
Homemade PVC kayak rack , can store 4 kayaks,paddles ,kayak car rack .made from 1.5" schedule 40 PVC 40"wide X 5' long (cost around $250 in 2015 prices) has 4 swiveling casters with two being lock kind ( otherwise rack will roll away when loading) . To make the wheel mounts I used 1 1/4" metal conduit cut to 2.5' long and weld a pre-drilled plate for the wheel . I bolted thru the PVC and conduit pipe to lock them together. The conduit helps reinforces the PVC when pushing the cart around .