My oldest son loves kayaking and bicycling. There is a beautiful lake not far from our home that he often frequents with his kayak or bicycles to and from. For him to kayak, it ultimately requires waiting for his mom or me to provide transportation, tossing the kayak atop the car, strapping it down and driving him over there. It's not that we don't want to, but for lean, muscular teenager, waiting for transportation from mom or dad, can be frustrating.
I built him a kayak trailer from used aluminum crutches (2 pair (4 crutches)) purchased from the Goodwill. They were purchased for less than $4 a pair. Aluminum crutches are consist of 1" and 1/2" diameter tubing. The crutches were taken apart and all piece parts saved. One pair was bent with a tube/pipe bender to make the main frame portion. Wheel and pneumatic tire assemblies were bought from Harbor Freight for another $4 each. The trailer tongue was fashioned from a crutch and bolted to the main frame. A 1" diameter dowell was inserted into the end of the tongue, so a 1" diameter eye bolt could be screwed into the end to form the trailer portion of the hitch.
The spare parts from the crutch were used as padded supports on the main frame as shown. An old bow pad was drilled with a 1" spade bit to allow it to be slid down the trailer tongue for additioal support of the kayak.
Two pieces of 1/2 " metal electrical conduit 24" long were placed on the lower portion of the bicycle frame. To hold in place I used stainless steel 2" adjustable hose clamps (2 each). Above either side the the rear axle of the bicycle frame are two metric threaded bolt holes which are used for accessories. After assembly was attached to bike frame, I covered the hose clamps with PVC electrical tape.
I retapped them out to 1/4" by 20 and ran threaded bolts throught the conduit to the frame for additional support. You will have to cut the bolts to length as to not to interfere with the derailer. I fashioned a hitch block out of some leftover pressure treated lumber and ran a 2" pipe clamp for the bicycle portion of the hitch assembly. This assembly is attached to the 1/2" metal electrical conduit by sheet metal screws from the sides and to the top.
I retapped them out to 1/4" by 20 and ran threaded bolts throught the conduit to the frame for additional support. You will have to cut the bolts to length as to not to interfere with the derailer. I fashioned a hitch block out of some leftover pressure treated lumber and ran a 2" pipe clamp for the bicycle portion of the hitch assembly. This assembly is attached to the 1/2" metal electrical conduit by sheet metal screws from the sides and to the top.
On the trailer, the Pelican kayak is strapped down with standard 1" webbing tie down and the bow is held in place with a bungee.
My son is now able to ride over to the lake (after his chores are done) and enjoy kayaking to his heart's content. (Did I mention there is a "small" mountain between our house and the lake?) The weight of the trailer is only a few pounds (aluminum crutches weigh next to nothing) and his kayak is but 26 pounds at most with oars, PFD and miscellaneous equipment.