have a buddy who carries a bunch of tip-ups around. he built a 3/4 inch plywood base with a box in the middle made from the same plywood, he then cut some heavy 4-5 inch (or whatever size your tip-ups) PVC about 18 inches long and set those around the box, there are 2 holes drilled through the PVC and lines up the pipes to the box and marks the holes on the box and drilled holes through the box. Attach the PVC to the box usung bolt and washers. The base would have to extend out enough so a row of PVC tubes can be attached to the outside of the box and still rest on the base. He has a handle added to the box. The box has no top but he made it the size to fit a couple plastic tackle trays in there. A picture would be worth a thousand words. This thing works well, I just cringe when we have to haul all his stuff around and we end up using two tip-ups.