How do hydrofoils work?

Sean and Robot have been using the Boatadex to figure out how hydrofoils work – they look cool but they can help craft go faster too.

The very first hydrofoils were seen in the late 1860s when an inventor called Emmanuel Farcot came up with a plan and if you look at his design, he was using many little foils along the side of his boat to lift it out of the water.

The main reason people install hydrofoils is to decrease the drag of the boat as it travels through the water. By decreasing drag, boats are able to travel at higher speeds while burning less fuel. It also means a smoother ride for the people on board so could be a good choice if you get seasick!

Hydrofoils are also used in sea planes too. Putting foils on seaplanes makes the landings smoother and takeoffs much quicker. The plane can get out of the water much faster with foils because there is less drag holding the plane back and stopping it from gaining speed to get airborne. Which is pretty handy if you haven’t got much water, like when taking off on small lakes or in rough water.

Hydrofoils create lift using the same science that gets planes to fly. It’s all to do with differences in pressure on either side of the wing – or in this case foil. Foils create lift when the water travelling over the top surface of the foil goes faster than the water travelling over the bottom – and is happens because the top of the foil is either curved or angled.

They can give even tiny boats a power boost. Because there is less surface area “rubbing” on the water to slow the boat down. This means that even with gentle winds, a small boat can really get moving.

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