Next, I cut the 4x4 into two sections and attached scrap carpet as padding, using Monel staples shot from a T-50 stapler. I secured the padded blocks with galvanized deck screws from below. I used 4-by material since the skeg on my boat is 4 inches tall, allowing the blocks to hold the boat upright while the skeg fits in the slot between them. Then I simply slid the bicycle tires on and secured them with double nuts. I say "simply" but I had to re-tap the nuts for the coarse thread rod (I tried to buy fine thread rod to match the nuts but couldn't find it locally). As a finishing touch, I secured a length of web strapping to the blocks with stainless-steel screws and cup washers. The idea is that these will hold the skeg. I intend to place the stern/skeg in the slot between the blocks and push the boat across the street. The strap will keep the cart in place under the boat.