Are you interested in a hydrofoil for your pontoon or tritoon boat but wondering what makes one hydrofoil different from another? Hydrofoils have been around for a long time, and since the launch of the Alexander Graham Bell 1906 Hd-4, the research and formulas for hydrodynamic lift have been refined and proven. We know that as a hydrofoil watercraft increases speed, the hydrofoil produces more lift which raises the pontoons out of the water, greatly reducing drag. By reducing drag, boat speed and fuel efficiency increase. It’s all in the math! Let’s go over a few basic rules to help understand the amount of lift a pontoon/tritoon hydrofoil will produce. For this discussion you will need to understand the following fundamental terms:
Angle of Attack (AoA): the degree of angle for a given hydrofoil or wing. A larger positive # (angled up in front) usually creates more lift as it increases. A negative # (angled down in front) usually decreases lift as the # increases. For this discussion we will use a moderate angle of 2 degrees AoA.
Knowing a bit about drag and the other 5 basic concepts, let’s put it all together.
Rule 1) Doubling the Span of the hydrofoil will approximately double the amount of lift generated. As the area of a hydrofoil increases, it’s lift percentage increases close to a 1to1 ratio.
Example: Using 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”, the 2x longer tritoon hydrofoil will create 2399 lbs. of lift which 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 boat needs, and 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 a hydrofoil that is sized incorrectly for a boat – it will not produce the needed lift or provide maximum performance.
Rule 2) Doubling the AoA will add 50% more lift. Starting with a 2 degrees AoA and doubling it to 4 degrees, the lift generated would increase from 1061 lbs. to 1571 lbs., an increase of 510 lbs. The ease of adjustability of the VARA® Foil gives our designers the flexibility to calculate and achieve more or less lift depending on your boat needs with our range of -5 to +6 degrees of AoA adjustability feature. This adjustability also sets our designs apart from what is currently available in the industry.
Rule 3) The square of speed. 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” hydrofoil span and our boat speed is 15 mph, we create 377 lbs. of lift, and at 30 mph, we create1509 lbs. of lift. At 45 mph, we create 3390 lbs. of lift. So, you can see that speed is a hydrofoil’s friend! Our engineers use this speed/lift ratio to offer you maximum performance for your boat needs and provide a lift graph of recommendations with your VARA® Kit.
When you add a VARA® Foil Kit to your boat, you receive a guarantee a 25% speed increase. Although, 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 @ 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.
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 can’t offer the benefits of a VARA® Foil at a comparable price.
Pontoon Hydrofoil, Size, Speed & Design Matters-Its 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.
Thanks for reading!
Mike Gable, PHA, Inc.
11-13-2023
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