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mmd
01-30-2018, 10:56 AM
The wFoil 18 Albatross, purportedly capable of 90mph:

https://gajitz.com/wp-content/uploads/2012/09/wfoil-18-albatross.jpg

https://images.fastcompany.net/image/upload/w_596,c_limit,q_auto:best,f_auto,fl_lossy/fc/img2-2.jpg

switters
01-30-2018, 11:09 AM
Does Chesapeake Light Craft know about those?

Nicholas Scheuer
01-30-2018, 11:12 AM
Where does one need to go at 90mph? Insufficient room for a family or friends; probably can't transport enough beer for a group of guys, eh?

mmd
01-30-2018, 11:17 AM
^Iceboating?

Figment
01-30-2018, 11:20 AM
For some reason, the first thing that comes to my mind is a very dramatic pitchpole.

mmd
01-30-2018, 11:31 AM
https://s-media-cache-ak0.pinimg.com/originals/3c/db/bf/3cdbbf553fc44eab545a2f39ca7330ef.jpg

Canoez
01-30-2018, 11:38 AM
For some reason, the first thing that comes to my mind is a very dramatic pitchpole.

Involving a very uncharted rock.

mmd
01-30-2018, 11:41 AM
For some reason, the first thing that comes to my mind is a very dramatic pitchpole.

Involving a very uncharted rock.


You can do that with a garden-variety Hobie cat:

http://www.johncaseyworldwide.com/wp-content/gallery/wipeout-wednesday/ek-hobie-cat-2009-italie-7621.jpg

Canoez
01-30-2018, 11:44 AM
Paddle, Michael. Paddle.

:d

mmd
01-30-2018, 12:00 PM
^ OK...

https://i.pinimg.com/736x/c1/70/28/c17028b2350194cc6dcfdcb4d96dae5f--pedal-boat-boat-design.jpg

Canoez
01-30-2018, 12:02 PM
:d:d:D

Garret
01-30-2018, 12:32 PM
For some reason, the first thing that comes to my mind is a very dramatic pitchpole.

Involving a very uncharted rock.


You can do that with a garden-variety Hobie cat:

http://www.johncaseyworldwide.com/wp-content/gallery/wipeout-wednesday/ek-hobie-cat-2009-italie-7621.jpg

Or a Nacra 17 & no rock at all. The trapeze ride is "entertaining"! DAMKIKT...

mmd
01-30-2018, 01:30 PM
Now this one is truly odd - hydrofoils gone wild...

http://sailinganarchy.com/wp-content/uploads/2014/07/render_hq_006-2.jpg

http://www.bluebird-electric.net/boats_images/quadrofoil-radical-hydrofoil-electric-watercraft-stern-drive.JPG

http://www.bluebird-electric.net/boats_images/quadrofoil-radical-hydrofoil-electric-watercraft.JPG

Keith Wilson
01-30-2018, 01:34 PM
But why in the world push on air, instead of much denser water? There are excellent reasons that boats have propellers below, rather than above.

http://forums.sailinganarchy.com/uploads/monthly_04_2014/post-105471-0-99799700-1398618554_thumb.jpg

Gerarddm
01-30-2018, 01:50 PM
I'm sorry, it's a dumb design exercise. A solution waiting for a problem.

Arizona Bay
01-30-2018, 01:54 PM
Needs wings!

mmd
01-30-2018, 01:58 PM
Keith, in an effort to defend the absurd...

There is a point of speed where the drag on a submerged propulsor is greater than the inefficiencies of propulsor operating in the air above, resulting in greater speed than if the same horsepower were operating through the water.

Garret, yes; but whom is to deny the nutty professors of the world. Folks said Alexander Graham Bell was wasting money and time playing with hydrofoils on Bras D'Or Lake in 1908.

https://tce-live2.s3.amazonaws.com/media/media/6cecea23-75d7-45b5-b758-2f53a1b5bce7.jpg

Garret
01-30-2018, 02:01 PM
Keith, in an effort to defend the absurd...

There is a point of speed where the drag on a submerged propulsor is greater than the inefficiencies of propulsor operating in the air above, resulting in greater speed than if the same horsepower were operating through the water.

Garret, yes; but whom is to deny the nutty professors of the world. Folks said Alexander Graham Bell was wasting money and time playing with hydrofoils on Bras D'Or Lake in 1908.

https://tce-live2.s3.amazonaws.com/media/media/6cecea23-75d7-45b5-b758-2f53a1b5bce7.jpg

Not I! I wish there were more.

Keith Wilson
01-30-2018, 02:55 PM
Keith, in an effort to defend the absurd... There is a point of speed where the drag on a submerged propulsor is greater than the inefficiencies of propulsor operating in the air above, resulting in greater speed than if the same horsepower were operating through the water. 475 MPH? :d

Thus surface-piercing props.

https://media.licdn.com/media/p/7/000/1b0/146/15818fc.png

Figment
01-30-2018, 02:55 PM
Now this one is truly odd - hydrofoils gone wild...

http://sailinganarchy.com/wp-content/uploads/2014/07/render_hq_006-2.jpg

http://www.bluebird-electric.net/boats_images/quadrofoil-radical-hydrofoil-electric-watercraft-stern-drive.JPG

http://www.bluebird-electric.net/boats_images/quadrofoil-radical-hydrofoil-electric-watercraft.JPG

Tubercles on the leading edge of the foils? I don't think I've seen that before. (except whales, natch)

Canoez
01-30-2018, 03:09 PM
When I did fluid mechanics work, we were focused on having the trailing edge be rippled or notched to avoid flow separation, vorticies and downstream drag effects. The only reason that we'd do something like that was to trip the boundary layer to simulate much larger foils, and an earlier transition from laminar to turbulent flow. Maybe they're using separation and cavitation to lower surface friction?

If I recall correctly, submarine racing teams would put a slot on the hull just before the length where the surface flow would turn turbulent and duct it to the rear of the sub. They might have several of these devices depending on length and hull speed.

beernd
01-30-2018, 03:12 PM
^ OK...

https://i.pinimg.com/736x/c1/70/28/c17028b2350194cc6dcfdcb4d96dae5f--pedal-boat-boat-design.jpg

WOW is all I can say :cool:

mmd
01-30-2018, 04:04 PM
Keith, all I can say is one of my favourite pithy statements from an old guy:, "For every problem, there are ten or twelve answers. Two or three of them are often correct," God love the wacky inventors; occasionally they get it right.

Chris249
01-30-2018, 04:20 PM
Hydrofoils! Bah humbug! Ptooey!!!

Actually foilers are cool and fun, but so many of the sailing world's media and officialdom are wetting their pants over them these days that it's bizarre. Almost no one is buying them and the numbers of the oldest foiling class, the Moth, are static, but superficial people who don't own racing boats are still telling everyone else to go out and foil. The funny thing is that I don't know of a single member of ISAF or the sailing press who has actually done what they tell others to do.

It's not the boats; they're cool. It's just that the "opinion leaders" and some unhinged fans are claiming that they are the future of the sport despite their cost and practicality issues, and that's an example of the way the sport has lost its way and lost its ability to actually think deeply or do any research on the affects of technological development on participation rates. Arguably, the fascination with foils is an example of harmful elitism in an era when the simple sports like SUPping are the ones that are growing.*

Ironically, I only just realised that I used to sail (and still own) what was arguably the first semi-foiling class; that is one that used the vertical lift of a foil in the water to increase speed. That's why foiling feels so familiar. And in typical fashion, that prehistoric semi-foiling class became extinct because it became too inaccessible for the average sailor.


* Yes, there may be foiling SUPs but go into any store or look up most ads and the foilers are being basically ignored by the mass SUP market. Sailing should IMHO do the same.

Phil Y
01-30-2018, 09:23 PM
Or a Nacra 17 & no rock at all. The trapeze ride is "entertaining"! DAMKIKT...
Me too.

JayInOz
01-31-2018, 01:02 AM
The wFoil 18 Albatross, purportedly capable of 90mph:

https://gajitz.com/wp-content/uploads/2012/09/wfoil-18-albatross.jpg

https://images.fastcompany.net/image/upload/w_596,c_limit,q_auto:best,f_auto,fl_lossy/fc/img2-2.jpg

I'll bet the noise from that engine/prop would be incredible. And you're sitting in the exhaust? And if anything falls off the motor, you can catch it in your teeth:) Does look like fun though.

DGentry
01-31-2018, 08:31 PM
https://oldmachinepress.files.wordpress.com/2016/01/2007-t-108-freri-siai-ar.jpg

skuthorp
01-31-2018, 08:36 PM
We had a couple of just obsolete foiling Moths at our regatta, A$40 grand new. Worth at present half second hand. Tomorrow scrap carbon fibre.

skuthorp
01-31-2018, 08:37 PM
https://oldmachinepress.files.wordpress.com/2016/01/2007-t-108-freri-siai-ar.jpg
TWO steering wheels for two rudders??????