I just made a cattrack for way less than $500 and its as good as the Cattrax version.
Go to Seitec and get a set of wheels.
I used the A wheels $59 each.
http://www.seitech.com/product_details.a...mp;riIDClass=92If you want the fat wheel they are the F wheel, $94 each
http://www.seitech.com/product_details.a...mp;riIDClass=92Get a section of 2"OD aluminum as wide as your boat, and 1" aluminum for the axles. The ID of the Seitech wheels is 1". 2" OD Aluminum is available at Dwyer or your local aluminum distributor
http://www.dwyermast.com/items.asp?cat1I...Aluminum+TubingThe 2"0D tubing is $8.60 per foot. You'll need about 8 ft
The 1" OD tubing is $5.40 per foot. You'll need 2 ft for the axles.
You'll need to get some Delrin to go from the 1"3/4 ID alum tube to the 1" Axle. Get a 12" long Delrin Rod round from McmasterCarr.
Part # 8579K38, $47 for one foot and you'll have some for your next set of wheels.
Assembly
I put the wheels on the OUTSIDE of the boat, its more stable, but you'll need to make the 2" tube as wide as the boat.
Cut 4 2" pieces off the delrin rod, and then drill 1" hole in the middle, so the axle fits into the delrin, which will slide into the 2" 0D tube. (The ID of the 2" is just over 1 3/4", and once you put a bolt thru the 2" tube, the delrin and the axle, its nice and solid.
Drill two holes in the axle, delrin and 2"tube, so that you can bolt the whole assembly together.
Bolt cradle on the 2" tube.
So, now you have a 2" tube as wide as our boat, with 1" aluminum sticking out the ends. Put the wheels on the ends and bolt the cradles to the 2" alum tube in the right spot.
Your wheels on the outside will be much more stable on rough ground and you wont risk hitting curbs or rocks that the wheels dont roll over.
Bill
