Designed for outboard power, all square stern canoes feature a transom gusset of tough .125" aluminum, motor pads to secure outboards and ribs for added stiffness. Stability is a top priority for the Grumman square stern, available in 16, 17 and 19 foot lengths.Tough as nails. Designed to last and perform, every Grumman® Canoe is hand-crafted from a special age-hardened, stretch-formed aluminum alloy substantially stronger than traditional alloys. ◦Each Grumman Canoe is hand riveted with specially-designed T-6 Alumilite rivets for maximum strength along gunnels, keels and ribs. The stretch-forming process permanently shapes the curves designed into the bow, stern and sides for maximum strength. ◦For added rigidity and unbeatable strength, Grumman Canoes use die-formed aluminum ribs and thwarts, and solid aluminum extruded gunnels.