DIY Party Barge Plansby Pauline Gill
Barges are flat-bottomed, shallow-draft watercraft that were originally used to carry freight and cargo on calm rivers and lakes. They are usually not powered and require tugs or push-boats. Heavy work barges are used as a stable platform for dredging and construction projects. In recent years, barges have found their way into recreation. Party barges with wraparound seating and fun-time amenities just beg for an occasion to get the gang on board for a day of festivities. Here is a design that incorporates surprising performance along with comfort and versatility.
Basic Party Barges
Most entry-level to mid-grade party barges integrate an aluminum frame and a carpeted marine plywood deck over two aluminum pontoons to supply buoyancy and a somewhat streamlined hull profile to the water. The pontoons are displacement hulls, however, and require far more power to move through the water than the planing hulls of normal runabouts that run on top of the water. All displacement hulls have a terminal velocity defined by the hull’s length because the craft cannot go any faster without creating a vacuum behind it. From that point, adding power merely generates more turbulence and wake with no increase in speed. Therefore, most party barges traverse the water at moderate speed at wide-open throttle and leave huge wakes.
Nuclear submarines running at high speed underwater face the same issue. They overcome it by streaming air bubbles out at the nose of the sub, which effectively lowers the resistance of the hull moving through the water. This same influence can be put to work on the party barge to noticeably improve the performance. Most party barges have a single outboard engine pod on the extreme aft between the two pontoons. This novel design puts one smaller outboard engine in front of each of the two pontoons. While the main thrust of each propeller is directed under and not at the pontoon behind it, the entrained air in this turbulence quickly rises to the surface and moves along the surface of pontoons until it reaches the rear-most section and breaks the suction behind it. The other positive effect is that the outboards also tend to flatten the surface before the boat gets to it, which smoothes the ride.
Barges designed for a single 50-horsepower outboard motor should get two front-mounted 30-horsepower units. A 90-horsepower design should get two 50-horsepower units. Beam cages will need to be constructed from the front of the pontoons to provide twin transoms in front of the barge. These transoms should then have half-eggshell baffles on the front to protect the motor connections. These should be made from fiberglass over hard foam. Wiring, steering and other controls, including fuel, should be moved forward. Batteries, fuel tanks and all other mechanisms should be moved aft to a platform extending between the two pontoons to help offset the forward weight. The captain’s helm should be moved rearward into a raised, center console-type helm at the extreme rear of the barge. This will help offset some of the forward weight.
The rear-mounted raised helm provides an exhilarating view of the entire ship as it moves forward smoothly and powerfully with its new power and operating strategy.