This versatile 3-in-1 "boat" can be paddled, rowed or outboard powered. An extra-wide beam and "Bulb T" keel gives it added steadiness and strength.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.The special "Bulb T" keel on Grumman"s 15" Sportboat and 19 ft. Square Stern makes larger canoes stiffer and stronger. Both keels are made of tough, solid aluminum extrusions. 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.