The Gunboat Mk.II, code named (Narwhal), is a bigger, badder, and improved version of the previous gunboat design. The biggest difference is the addition of a deeper hull which significantly improves buoyancy in the Narwhal. I also added a slot along the keel so that a penny can be used for ballast. The penny fits really tightly; however, the ballast is not necessary as the vessel still floats great without it. Furthermore, no support structure is needed for this print. The boat/toy is fun for for kids of all ages: great for the tub or pool. Hope you enjoy and happy boating!