Foiling boats.
 

https://m.youtube.com/shorts/Z1Fm-LCpj9A

https://m.youtube.com/shorts/Z1Fm-LCpj9A

I always thought the old Hydro foils from back in the 60s were cool and now that foiling boats have taken over in high speed racing sail boats I’m surprised that it hasn’t been applied to some high speed cats.

I can see it would need to have some progressive foils that would need to be of less surface as the speed dramatically increased but it would be an interesting endeavor to conquer.

What do the Offshore rules say about foiling race boats?


https://m.youtube.com/watch?v=2i2Zf9WVlNY&pp=ygUbRm9pbGluZyBlbGVjdHJpYyB yYWNlIGJvYXRz


Explanation of the foil control

https://m.youtube.com/watch?v=H7oPQGPAXu4

Quote to have links appear. What’s still up with that OSO ?

again

First video, the Candela is a nice looking boat.
I’m not sure about the seas, at first, that was nasty water. When he was up and running on the hydrofoils, it looked a bit placid.

What would a drive that can handle bigger hp look like when lowered 3’ below the boat?

I’m glad I watched the second video to tne end when he answered the question “Why hasn’t anyone done this before?” :)

RR

Not thinking about electric motors just the foiling idea.

I will say as exciting as the added speed is on the foiling Americas cup sailing cats they’re boring compared to the old F40 class .

I think for power outboards on a rear foil that would progressively lower with the forward foils as speeds increased would be the trick.

Foil heights would be optimized for 3-4 waves but think about the control they would have in controlling blow overs with their interaction speeds

I’m curious what the drag of a small foil would be compared to hull hydrodynamic drag at 150 mph.

Something similar to breaking the sound barrier in air occurs in water at speeds between 45 and 60 mph, depending on the hydrofoil and wing loading. Ride above this speed means dangerous dynamic pressure shocks and extreme water resistance.
Surface propulsion solves this problem with propellers by using an air cushion, and modern super-fast torpedoes solve this problem in a similar way, but for the load-bearing elements of a speedboat, this would not be a safe solution.
In addition, at high speeds, a speedboat on a pad keel or a catamaran with air tunell have much less drag than an adequate hydrofoil.

I've always been intrigued by hydrofoils
Thank you Plavutka for the explanation on the limitations.
This is a Canadain Navy ship that was launched in 1960's using hydrofoil technology

You're spot-on with your post from a quick conversation I had with Pete about hydrofoils. He said they lose their speed advantages past 50mph or so. Obviously, this was in context of high-performance catamaran powerboats, I can't say the same would hold true for sailboats and/or other displacement type hulled boats.

Speed ​​limits apply to all hydrofoils, regardless of propulsion. No commercial hydrofoil goes over 50 mph because it becomes dangerous to the wing structure.
About 15-20 years ago, a French sailboat - foil catamaran was setting a lot of speed records until it exceeded 48 mph on a Mediterranean cruise and broke apart due to pressure shocks in the foil structure.
Surface propellers spin at a peripheral speed well above the "speed of sound" for water, and if you look at the foil of a performance clever prop it is not too different from a rocket wing, or the rudder of an X-15 aircraft, because they are moving under very similar conditions. OK, cup..., but basic it is the same.