A pontoon framing system using complimentary cross members and pontoons to form a pontoon frame. Making the pontoon is done by providing a flat sheet of material that has lateral edges. Rectangular notches extending inwardly at lateral edges are located opposite each other. The sheet is rolled into a cylinder so the notches in the sheet form a notch into the final cylinder that forms a central portion to the pontoon. The lateral edges are joined, and this is typically done by welding. A cross member having a rectangular cross section is placed into the notch formed in the cylindrical central portion. The cross member is then joined to the cylinder.The complimentary shape of the cross member and pontoon may also be produced by having a cylindrical central portion and then removing an arcuate portion of material in the cross member to match the shape of the pontoon.