What a Hydrofoil is and Why You Need One
If you’re not familiar with what a boat hydrofoil is, let us explain. Created for boats up to 25 feet long, a hydrofoil is essentially a curved wing for the water that’s mounted to an outboard engine’s small “cavitation” plate. Similar to an airplane wing, a hydrofoil directs water flowing out from the propeller downward. As a result, the hydrofoil and entire rear of the boat (stern) are pushed in the opposite direction upward.
By extending the boat engine’s built-in cavitation plate with a hydrofoil, the chances of the propeller drawing in air and creating an air cavity are greatly reduced. Air pockets around a propeller can cause an engine to rev to high rpms while the boat struggles to go anywhere. Hydrofoils capture the water pressure that would normally escape to the top and the sides, holding more of it in close proximity to the propeller. Not only are air pockets eliminated, this pressure also creates a more powerful level of forward thrust.
Once the stern area is pushed higher up onto the water in this fashion, the entire boat remains level under throttle instead of bogging down in the rear and rising too far up in the front (bow). This is known as “getting the boat up on the plane”, where the boat appears to be gliding on top of the water at speed. The reduction of drag that occurs on plane leads to even quicker and more efficient performance in the water – saving time, fuel, and engine wear. For situations where an engine is underpowered for the size or weight of the boat, hydrofoils have been shown to deliver noticeable improvements in performance.
In addition, a level boat does not suffer the same degree of pronounced bouncing over waves that occurs when the bow area is raised too far upward. Any time the boat is in motion, a hydrofoil will yield a ride that’s smoother, less jarring, and more stable – especially as speeds increase and waves become larger. You and everyone aboard will physically feel better and continue to enjoy the boating experience much longer, reducing unwanted “drop me back off at the dock early” requests.
When it comes to watersports activities, hydrofoils add to the quality of life as well. Experienced waterskiers will be happier with your boat’s faster out-of-the-hole responsiveness, and you can maintain lower planing speeds without constant throttle adjustments if you’re towing beginning skiers, wakeboarders, or anyone in a tube.
In short, this inexpensive, easy-to-install, and mechanically simple part known as a hydrofoil allows you to operate and maneuver your boat like an experienced pro. And, for pennies on the dollar, you’ll get performance and efficiency gains without making a single engine modification.
Another common issue hydrofoils correct is “chine walking” which can occur on performance boats at higher speeds. If the bow is angled upward excessively, the boat’s hull can lift off the surface of the water to the point where the contact patch is minimized too much. Balancing the hull straight on its keel becomes difficult, and much more steering corrections are required to prevent the boat from bouncing left to right continuously. With the stern pushed upward, the front is lowered and the hull maintains proper contact with the water.
If you’ve got a deep V boat where a larger portion of the stern sits deeper than the bow, slow speed wander (or “deep V wander”) can occur when water rushing along the sides of the vessel collapses into the hole behind it. Swirling vortices create suction on each side of the transom that ends up pulling the boat rearward and to the left.
Let’s take a look at the hydrofoils we recommend.
Trolling Plates for Small Electric Motors
We’ll start with trolling plates designed for slow-speed electric trolling motors. These feature an adjustable flap designed to reduce trolling speed down to a desired 1 mph crawl when it’s in the down position in front of the propeller, then act like a traditional ride stabilizer once it’s in the up position. Choose the Davis Instruments stainless steel Happy Troller Trolling Plate or the Ironwood Pacific stainless steel Easytroller Stainless Steel Trolling Plate if you prefer manual control of the flap. The T&L hardened nylon Trol-A-Matic Trolling Plate features a flap that swings up automatically as speeds increase.
2-Piece Hydrofoils for Small Boats & Engines
When it comes to best values for smaller boats such as inflatables, jon boats, and other lightweight craft, we’ve got 2-piece hydrofoils including the Davis Instruments Doel-Fin Hydrofoil, Attwood Hydrofoil, Sea Sense Hydrofoil, Stingray Hydrofoils AIRO Hydrofoil, and T-H Marine Hydro-Tail Hydrofoil. These are typically flat all the way across and shaped like the wings of a fighter jet. However, we’ll note that the Stingray Hydrofoils AIRO Hydrofoil does feature pronounced curvature for better lift on heavier small boats.
1-Piece Hydrofoils for Medium-Sized Outboard Engines
Compared to two-piece hydrofoils, single-piece ones deliver stronger performance thanks to greater surface area that results from overhang extending out past the propeller. The Stingray Hydrofoils Hydrofoil represents a best value pick in size choices of “junior” for small engines up to 40 horsepower and “senior” for bigger motors up to 300 hp.
We also offer SE Sport’s 200 Series Hydrofoil and 300 Series Hydrofoil which can be bolted in place or attached to the cavitation plate with an optional clip instead. (We’ll note that if you’re travelling at higher speeds and/or in rough water, you may prefer to secure your hydrofoil with screws instead of clips). For those that prefer lightweight construction, the Davis Instruments Whale Tail Hydrofoil is crafted from high grade aluminum and features an overall shape that curves down at the sides for better performance.
Hydrofoils for Maximum Lift
The Stingray Hydrofoils Classic Pro Hydrofoil features larger wings for maximum lift and stabilization on big engines with powerful thrust. Stingray’s XRIII Hydrofoil features a high degree of curvature across the entire width of its wings in order to pack water more tightly around the propeller and cavitation plate. This creates great lift, and it’s also recommended for the pontoon boat owner who’d like to make sharper turns without throttling down. The SE Sport 400 Series Hydrofoil features a crescent-shaped surface designed to direct water for better handling and thrust-cutting at speed.
The Stingray Hydrofoils Hyperfoil 500 Red also features a higher degree of wing curvature. Designed for the professional bass boater who needs to reach top speed quickly in order to get to schools of fish as soon as they’re detected, this is an excellent choice for powerful speedboats. Additionally, Stingray recommends their Stinger Hydrofoil for significant lift on smaller boats and engine setups while providing larger boat and engine setups with improved launches and maximum top-end speed.
In addition to the hydrofoils covered here, we also offer a selection of trim tabs and powerful compact directional thrusters - along with a full array of hardware and components related to each.
And when it comes to everything else, we’ve also got the boating items you want and need such as electronics and navigation equipment, must-haves for interior cabin & galley areas, items for on-deck, replacement engine parts and hardware, plumbing-related items, maintenance, and other upgrades to make the boating experience more enjoyable. Whatever you’re looking for, we’re confident you’ll find the right products on the digital shelves of our online store. Visit us at www.BOATiD.com for all your marine needs, or contact our knowledgeable specialists at 888-453-5144.