Are you interested in a hydrofoil for your pontoon, tritoon, or power catamaran? Perhaps you are wondering what makes one hydrofoil different from another. Hydrofoils have been around for a long time. In fact, Alexander Graham Bell launched HD-4 back in 1906. Since then, research and formulas for hydrodynamic lift have been refined and proven.
We know the science: as a hydrofoil watercraft increases speed, the hydrofoil produces more lift. This process decreases wetted surface and parasitic drag while keeping a stable platform with less boat in the water. Consequently, by reducing drag, both boat speed and fuel efficiency increase. It’s all in the math!
Let’s review a few basic rules. These rules will help you understand the amount of lift a pontoon/tritoon hydrofoil will produce. For this discussion, you will need to understand the following fundamental terms:
Fundamental Hydrofoil Terms
Span: the total length of corresponding hydrofoil, or wing.
Speed: the speed or flow of water over the hydrofoil. Our examples are calculated in MPH. Remember: going down current decreases water flow speed over a hydrofoil. Going into the current increases water flow speed over the hydrofoil. This usually produces more lift.
Angle of Attack (AoA): the degree of angle for a given hydrofoil or wing. A larger positive number (angled up in front) usually creates more lift as it increases. A negative number (angled down in front) usually decreases lift. For this discussion we will use a moderate angle of 2 degrees AoA.
Lift: the dynamic force perpendicular to the water flow direction.
Boat Needs: All boats have different specifications. These include speed potential, beam width, static weight, crew weight, length, center of gravity, horsepower, wave and water conditions, owner use, and performance needs.
Knowing a bit about drag and the other 5 basic concepts, let’s put it all together.
Rule 1: Doubling the Span
Doubling the Span of the hydrofoil will approximately double the amount of liftgenerated. As the area of a hydrofoil increases, it’s lift percentage increases close to a 1-1 ratio.
Example:
Use a stock tritoon with a max speed of 25 MPH. If we add a tritoon hydrofoil with the AoA set at 2 degrees, the amount of lift produced is 1061 lbs. If we double the span to 100 inches, the 2x longer tritoon hydrofoil will create 2399 lbs. of lift. That equals an increase of 1338 lbs. Both lift outputs produce different speed ranges for each application need.
Our engineering team at PHA, Inc. matches the hydrofoil size to your specific boat needs. Therefore, we do not sell a “one-size-fits-ALL” product.
Think of it like tires for cars. Not all tires will perform correctly on every car. It’s the same with an incorrectly sized hydrofoil for a boat: it will not produce the needed lift or provide maximum performance.
Rule 2:
Doubling the Angle of Attack
Doubling the AoA adds 50% more lift. If we double 2 degrees AoA to 4 degrees AoA, the lift generated will increase by 510lbs, from 1061 lbs. to 1571 lbs.
Adjustability is key. A VARA® Foil hydrofoil provides flexibility to achieve more or less lift depending on your boat needs. This adjustability sets our designs apart from others currently available in the industry.
Rule 3:
The Speed Factor
Speed is a hydrofoil’s best friend! Doubling the speed increases the amount of lift by 4 times. Tripling the speed increases the lift by 8 times.
For example: If we use a 50-inch hydrofoil span and our boat speed is 15 mph, we create 377 lbs. of lift. At 30 mph, we create 1509 lbs. of lift. Furthermore, at 45 mph, we create 3390 lbs. of lift. Our engineers use this speed/lift ratio to offer you maximum performance for your boat needs. We provide a lift graph of recommendations with your VARA® Kit.
The VARA® Foil Difference
When you add a VARA® Foil Kit to your boat, you receive a guarantee of a 25% speed increase. In fact, to date, none of our customers received any less than a 32% speed gain.
Just imagine getting a 69% increase in speed like one of our recent customers! With a huge smile on his face at 30mph, he said he was “Walking the Dog” with his 70hp 20’ pontoon boat, after doing 19mph max standard!
Remember, too, that fuel savings are considerably matched at 25-35%. Do the math to see how much money you can save on gas.
Easy Installation & Affordability
These kits are easy to install, affordable, fully adjustable, and require NO permanent gluing, destructive cutting, or grinding of the strakes or toons. No pontoon trailer mods are needed. A VARA® Foil kit can be installed in the water, on the trailer, or in a lift.
Furthermore, what other pontoon accessory or hydrofoil offers the pontoon/tritoon boater a 25% minimum increase in speed at an affordable cost? The answer is none. In addition, a new larger motor cannot offer the benefits of a VARA® Foil at a comparable price.
Pontoon Hydrofoil, Size, Speed & Design Matters—It’s SIMPLE Math. There are options for the pontoon and tritoon enthusiast to purchase. There are “wings.” There are “one size fits all” solutions. However, just keep in mind what your “MATH” will confirm: Our VARA® Foil will get your job done… guaranteed!
Schedule a call or email us with any questions you may have.
In Addition, join us for our next Blog where we will further discuss how adding a VARA® Foil hydrofoil system decreases the load on the engine and boat structure while decreasing maintenance costs.
Angle of Attack (AoA): the degree of angle for a given hydrofoil or wing. A larger positive number (angled up in front) usually creates more lift as it increases. A negative number (angled down in front) usually decreases lift. For this discussion we will use a moderate angle of 2 degrees AoA.
