The C-Tug is a very good cart, especially for kayak fishing for not having to unload your kayak to flip on side to insert the scupper cart. Just lift stern slide back onto cart.
I have had some slipping issues. My first problem was buckling the strap itself. You have to buckle it as specified in the directions (not how you would think to typically run the strap) or it will slip and loosen making the cart slip off your kayak. I was doing mine backwards tag end on top exiting the buckle. The strap actually enters the buckle first then the tag end goes out underneath to pull to tighten. I found that strapping correctly solved most slippage issues. A half hitch knot at the buckle once tight helps to hold buckle in place too. See the following strapping instructions.http://www.c-tug.com/uploads/files/english.pdf
The next issue was hitting a bump, curb, rock or other high uneven surface would tend to stop the cart but the kayak kept going once again falling off the cart.
I found the use of a footman loop on each side of the kayak to hold strap securely in place did the trick. Slide straps through the loops buckle as per instructions and you will have a secure hold on your cart.http://www.strapworks.com/SearchResults ... rch.y=-156
I hope this helps. I have a revolution but the footman loop solution will work on any kayak.