The "dillon mini tunnel" gt pro racing tunnelboat. redesigned for 2014 see the new plans. also available: cockpit plans can be adapted to the mini tunnel. Purchase online, then download start building today! the dillon mini tunnel: boat plans: a racing/recreational tunnel boat for 15 hp to 30 hp motors. The hull is about more than just good looks. the shape of the hull affects the speed, stability, and maneuverability of the rc boat. flat-bottom, monoplane.