Thought this was inventive. The direct link is below.

Building a Custom Kayak Cart

These plans are for a custom kayak cart. Special thanks go to Tom Powers for the extraordinary effort and detail of these plans.



NOTES.
  • <LI class=MsoNormal>Attach 2x4s with 7/16 x 3 ½ inch galvanized lag bolts. Two per joint. Assemble outside box first. <LI class=MsoNormal>Cut angle steel to length and attach to wheels. One of the center holes will have to be cut into a slot so that the cart can be maintained in the long run. <LI class=MsoNormal>Determine spacing between interior frame pieces and outside pieces based on spacing of angle steel. Attach interior frame pieces using 7/16” x 3 ½ inch lag bolts. <LI class=MsoNormal>1x4 or 2x4 cradle pieces cut to fit boat. Leave about ½ inch clearance to allow for carpet thickness. Mount with 2 ½ inch galvanized deck screws. <LI class=MsoNormal>Attach carpet to all surfaces that come into contact with the boat. Aluminum roofing nails work best. <LI class=MsoNormal>Attach wheels off centered with a more of the cart on the front end. This will allow you to drag the cart around easier when there is no boat on it. <LI class=MsoNormal>Attach a loop of rope to the front of the cart. This can be tied to the front of the boat and used for dragging the boat around the yard. <LI class=MsoNormal>If a back wheel from a bicycle is used you must open it up and remove the interior coaster brake pieces from the hub. Lawn mower wheel are available from Northern Tool and Supply. They last longer and are maintenance free. However, bicycle wheels work better on pavement or soft sand. Both work for short distances on most any surface.
  • Width options. In general narrower carts work better for storage, etc. Wider carts are more stable if you are dragging it behind a bicycle. In either case make sure that the wheels clear the boat by at least a few inches. This will depend on the width and shape of the boat.

Materials.
2 ea. 8 foot pressure treated 2x4s
1 ea 6 foot pressure treated 1x4 for cradle (can be 2x4)
1 ea. 4 foot galvanized 1 ½ x 1 ½ x 48 inch, angle steel
(the kind with pre cut slots and holes)

30 feet of ¼ inch to 3/8” rope.
16 ea. 7/16 x 4 inch galvanized lag bolts
16 ea. 7/16 x 2 ½ inch galvanized lag bolts
32 ea. 7/16 galvanized washers.
2 each 20” bicycle wheels*
or
*2 each 16 to 18 inch lawn mower wheels and
*2 each 5 inch x ½ inch galvanized bolts
*4 each ½ inch galvanized nuts
*8 ea ½ inch galvanized washers


Figure 2. Bicycle wheel and lawn mower wheel as mounted on different carts.


Figure 3. Wide cart with lawn mower wheels.


Figure 4. Narrow cart with lawn mower wheels.




http://images.search.yahoo.com/image...sigb=13j7g7tu1