Yes, there are many designs out there with either rigid or folding frames that the kayak needs to be secured to or need to be inserted into the scupper holes. Wheels that handle loose soft sand well have to be large diameter or wide. Due to the width of some kayaks this makes the assembly quite tall and or wide. This is something a little bit different in that it is held in position by cords in tension but is towards one end of the yak to keep the width down. With the wheels towards the rear, some weight needs to be carried when dragging from the other end of the kayak.
Step 1: Materials and Tools.
A pair of wheels. This is the most important item before you begin as it will drive your design. Look for golf carts in your local thrift store or re-purpose a pair of children's bicycle wheels? The largest diameter, non metallic are ideal to avoid corrosion and or flat tires. The ones I found were off a golf cart.
PVC plumbing tube and fittings, diameter and type to suit your design. This uses 5 elbows, 4 tees, 2 tapped reducers and 2 threaded caps
Rod or tube (stainless or anodized aluminum) for the axle. Diameter to suit the wheels.
2 hitch pins, 2 "S" hooks, cord, plastic scraps.
Saw or PVC tube cutter, PVC cement, Drill, File.
Step 2: Design
With your kayak upside down slide the wheels on the axle rod and position the axle on the kayak in the position you want. The closer to the back, the narrower the frame will be but the heavier it might be to haul while the nearer to the center you place them then wider the frame will be and the easier it will be to pull. I positioned the wheels so they were inboard of the kayaks width so the cords could connect to the kayak without rubbing the wheels. If the wheels are wider then the blocks and cord will need to be placed inboard of the wheels.
Layout your PVC elbows and tees in the rough locations and cut the tubes to approximate lengths erring on the long side since they can easily be shortened. Drill a hole to suit the axle diameter in two end caps or adapter pieces depending on what fitting you chose. Slide the tubes into the fittings to complete the frame assembly. Thread the axle the end caps and slide the wheels on. Adjust the various tube lengths until the frame sits neatly against and cradling the kayak hull. Take into account the disassembled state of the cart by reading the next step. Make all fittings with a dot to ensure alignment. Disassemble noting the order the pieces can be pulled apart. Reassemble in the reverse order using the PVC cement and aligning the marks.
Frame is complete. Once the cement is set slide in the axle with a wheel each side and set the kayak on top of it gently. Without support it might shoot out like a bar of soap.
Tie one loop around the rear of the kayak attached onto the toggle or with a carabiner.
Drill two blocks of plastic with one hole for the axle and another hole big enough to accommodate a knot in the cord you are using. Drill a hole the diameter of the cord to intersect this hole. Feed the cord into the hole and push the end out and tie a knot in the end and pull the cord back tight so the knot is in the hole but cannot pull through. Place the block on the outside of the wheels both sides and tie an S hook to attach to a deck feature. Adjust the hooks position until the frame is held tightly in place.
Slide the axle so only about 1/2" protrudes through the block on one side and then cut the axle to length to leave 1/2" protruding out the other side. Drill 2 holes through the axle for the hitch pins. If you blocks are inboard of the wheels you might like to incorporate a washer outboard of the wheel.
To avoid losing the pins I connected them to the cord with a plastic zip tie.
Step 3: Disassemble for Stowing
In the design step I positioned the stub ends cradling the hull about a wheel diameter from the end elbows so one wheel sits in the space. The other wheel sits outboard and the cords tie it together so not loose or lost parts. It also stands up on end nicely. The axle can be removed to make the storage space required a bit narrower.
Step 4: Project Complete!
Enjoy being able to cart your yak down to the waters edge more easily. Remember to load the cooler and any other heavy items at the back above the wheels to make it easier.