double wheels double the weight. would be loaded oddly when you go lift a wheel

I'm not worried much about the extra weight. My sailing will consist going straight one way down the beach a few miles and then straight back and I'm not going to be racing.

I would go with a larger diameter wheel if could find one, but I've been searching the WWW and can't seem to find anything better than what I have.

I'm probably getting ahead of myself anyway as I haven't tried my yacht on my beach yet. It will probably be fine as is.

My beach can be very variable so I run 20 x 12 slicks on the rear with a normal wheel barrow wheel on the front, overall the effect is beneficial keeps you moving in the soft stuff, takes the bumps and hollows.

its a great waay to make a cheap balloon tyre, the woomeral yacht club did it alot. . pull the second wheel off the axle when your on the hard. make a set of stubs and try it let us know the results

We use Beachracer tyres,
example;www.kitebuggys.nl/en/21-bigfoot-banden

Here's another way to arrange double-wheels: in-line:

Sorry for the poor quality photo, it's a small section of a wide-angle video frame.
I don't have any better photos, but the rear wheels are slightly staggered (i.e. stub axles sticking out of opposite sides of the horizontal connecting piece. IIRC the connecting piece pivots where the normal axle would be mounted so the tires can ride over bumps.



Video(Mike is at about 1:38):