# How to Make a Pontoon Boat Faster

by Will Charpentier

A boat operates at the boundary of two fluids, water and air. The pontoons of your boat move through a single fluid--water--and are affected by the same forces as an airplane: thrust (the power from the engine), lift (the planing capabilities of the pontoons), drag (the interaction of your pontoons with the water) and gravity (your boat's weight). This means that, to make your pontoon boat faster, it will be necessary to concentrate your efforts on the hull to increase lift, the power available to overcome drag, and the weight of the boat to decrease the effects of gravity.

## How to Make a Pontoon Boat Faster

Determine your hull's "design speed." With enough power, you can sail an aluminum john boat across a lake at 100 miles per hour, but if the john boat's square bow falls apart at 80 miles per hour, then the design speed of the john boat was less than 80 miles per hour. Because typical pontoon boats use displacement hulls and have no planning capability, the design speed can be approximated by multiplying the overall length of one pontoon by 1.5. Thus, the upper end of the performance envelope for a pontoon boat with pontoons 25-feet long would be about 37 miles per hour. To reach this upper end of performance, one of the four factors affecting the vessel must be changed.

Change the effects of gravity by lightening the vessel. Remove all nonessential personnel, fixtures and equipment from the vessel. The decrease in weight will mean that the vessel will "ride higher" in the water and your motor will have to push less pontoon through a very dense medium.

Increase the laminar flow of water around the pontoon hulls by cleaning the surface of the pontoons, removing any debris or marine life that has attached itself to the surface of the pontoon. If you leave the boat in the water for even a few days, you will find that algae will begin to accumulate on the surface of the hull. While it might seem that painting the bare hulls with marine anti-fouling paint would fix this problem, anti-fouling paint can weigh 14.6 pounds per gallon or more, while conventional marine paint weighs about 11 pounds per gallon, nullifying any savings in drag by an increase in weight.

Change your boat's thrust. Increase the thrust available to move the boat through the water by tuning or upgrading your boat's motor to obtain more horsepower. If this does not have the desired effect, it will be necessary to re-power your boat with a larger engine that produces more horsepower.

Change your boat's "lift" to reduce the drag on the pontoons. Drag is reduced by increasing lift, and lift can be increased by changing from displacement pontoon hulls to planing pontoon hulls. Pontoon boats are equipped with displacement hulls---the pontoons force their way through the water and have no lift, save that of their buoyancy. Recent advances in pontoon hull technology mean that planing hulls for pontoon boats are commercially available from some manufacturers. Planing hulls are zero-displacement "lifting" hulls, designed to have only minimal contact with the water, running on top of it.

• A calculator

#### Tip

• Remember that your hull is being pushed through a very dense substance: water is essentially incompressible at depths less than 6,732 feet beneath the surface of the ocean (204 atmospheres, or 2998 psi) and then, only by 1 percent; in the Challenger Deep of the Marianas Trench, water is compressed by only 5.67 percent at a depth of 36,201 feet (1097 atmospheres, or 16,120 psi).

#### Warning

• Sweeping changes to your boat may adversely affect the safety of waterborne operations.