Here are a couple of pics of the woodhauling flatsled that I made. The sled is 10 ft. long, 36" wide, 9.5" high. Runners were made out of 2"x6"s, for the front curve of the runner I usually make a 4 piece design so when I lay the 1/2" plywood on top and press it down it curves naturally without cracking up the plywood, while I am securing it in place. All the pieces are glued before I screw them together, makes for a stronger bond. The cross pieces 2"x6"x 36" and are there for support, makes the sled stronger for the days when you are hauling a heavy load of logs. They are spaced approx" 20" apart on center. On top of the crosspieces I bolted down a 2"x4" on each side, make sure you predrill the holes before putting in your lag bolts and use flat washers for each bolt. The slots you see in the pic are for running your rope through. Then on each side of the runners I covered the 2"x6" lumber runners with plywood to cut back on wear and tear of the runners on the trail, this is done on both side of the runners. Also makes the runners stronger so that a heavy load doesnt cause them to cave in when you are driving on a rough trail. When I built this sled I used Grip Rite Fastners Primeguard Plus Exterior Screws both 1-5/8" and 3" much stronger than nails. Last thing I need to do is put a couple coats of weatherproof paint on it to seal it up. Overall it is a good basic design out here, a lot of woodhaulers use the same design of sled. Over the years sled construction has been evolving, some woodhaulers now use homemade metal sleds, sleds that are made out of 2"-3" square metal stock. These sleds are very sturdy, maybe I will ask my friend if I can take a few pics of his sled to show on here.