I was wondering about the wheels, what a good idea. I presume they just slot into a tube or two in the deck?

Et

The wheels are used by about half of the competitors in the 19 mile race at the Run of the Charles. the wheels make it a lot less tiring if all goes well but they add some frustrations as well. The 19 mile race features 6 portages of the following lengths: 0.2 miles, 0.3 miles, 0.5 miles, 0.2 miles, 0.1 miles, and 0.1 miles. Most competitors kvetch about the third portage because of its length, however, in my humble opinion the 2nd, the 4th and the 5th are far tougher. All three feature very slippery rocks and steep banks at the takeout. Also the first, second, and fourth have lots of thin little trees, roots, and uneven ledge along the route that grab at soft boat shoes and wheel axels.

Lots of folks took a look at the wheels before the race. Some were favorably impressed, while others engaged in not so subtle psyops wagering that they would not last the race. I started by making sure I placed a backer of 18mm Baltic birch plywood in the stern of the deck that would hold screws.

A threaded insert with a 1/4"x20 threaded insert is epoxied into the deck to hold the assembly.

The wheels themselves are made of 6 mm thick Baltic birch plywood and are 6" outside diameter. They are reinforced with Kevlar fabric. The tires are 6" diameter O-rings. Wheel axel is a continuous length of pultruded carbon fiber tube that fits into another carbon fiber tube. Pultruded tube has very little hoop strength and it did split during the race. The CF tube was purchased from Dragon Plate. The leaf spring that connects the axel to the base is 6mm Baltic birch plywood covered with graduated lengths of 9 oz e-glass and some bias cut 6 oz glass. The bias cut glass reduces torqueing of the leaf spring.