[tony]

The seam in the middle of the scupper hole tubes is the weakest part of the kayak mold. Constant jarring and banging within those scupper tubes could break the seam and start a leak.If you dont frequently go a lot of distance with the cart it probably doesnt matter, but if you develop a leak later its probably the scupper tubes. If you want to be super safe, pad the poles that go thru the scuppers as well as the area of the cart where the kayak sits, and perhaps goop the scupper tubes from inside your kayak. Scupper tube leaks can also develop from cranking down too hard on your vehicle tie down straps.The scupper carts are fast and easy, so it might save you that valuable minute or so when a cold beer is screaming your name at the landing. Unless you like building your own stuff it might be easier and about the same price to find a used one (scupper or sit on/with strap). I built one from PVC and it kind of sucked, but others on this site that are more mechanically inclined have had success.