working home made cat trax

Just curious....do the drums rotate around the axle or does the entire axle rotate? If the former, won't the drum bottoms eventually split from the strain? If the latter, won't the boat just roll away from the wheels?

I'm not quite done yet, I am working on cradles for the hulls and I originally planed to shorten the pvc to where it is just going through the barrels, then mount the barrels to the pvc so the barrels wont ring out.

there is a metal pipe inside the pvc for support

I've seen this done before. It will work for awhile but the drums tend to get brittle and crack. There is just nothing better than the rubber wheeled cat tracks. I've made wheels from golf cart wheels and pipe, wooden wheels and frame and a similar set-up like yours with metal kegs.

Another idea. It seems that older 3-wheeler "big red" front wheels would be great to use and must be similar if not larger in size than cat-trax. They are on ebay for $15-$25 including rims. shipping might jack the price. Just a thought. Also, in Northern tool there are plastic dock wheels very inexpensive also.