I have a .5 mile walk to the lake to launch a new-to-me rowing shell. The shell is fragile so I needed a safe way transport the shell, oars, etc. I purchased a kayak cart for the stern and made a fabric sling for the cart since the supports were too wide for the shell. I made a sling with handles to carry the bow and "pull" the shell down the road but it was awkward going a mile round-trip. I also tried using the bow sling with a shoulder strap but again, it was awkward. I found Maker Pipe and rented a pipe bender to make a cart for the bow. With David's recommendation for pneumatic caster wheels and the Maker Pipe adapters for the wheel posts and my set of connectors (90, 180 and T), I was able to build a cart that allows me to easily roll the shell to the lake and back. The shell is suspended from the center bar using a bungee cord connected to the sling I made and the shell is level bow to stern. The cart shape keeps the boat from touching the cart when I turn so I don't have to worry about damaging the shell. I am so happy with this solution to my problem -- not sure how I could have solved this without Maker Pipe. :-)
Any detail on the casters that were used?
"I think something like this would do the trick for the next build. We could make you an insert to fit these into the ends of conduit."
https://www.wttool.com/index/page/product/product_id/39802/product_name/Shepherd+Institutional+Series+Pneumatic+Casters?gclid=EAIaIQobChMImM3g5rW26wIV54FaBR2J5g_MEAQYBiABEgIEyfD_BwE