
How a Boat-Plane Hybrid Shattered the Sound Barrier of Sailing - jchrisa
http://www.wired.com/autopia/2013/01/ff-paul-larsen-sailrocket/all/
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startupfounder
"Vestas are one of the worlds leading developers and manufacturers of wind
turbines for whom Malcolm is a senior test engineer."
(<http://www.sailrocket.com/node/136>)

Very cool that a senior test engineer from the worlds largest with turbine
manufacturers is able to take his domain knowledge and build a craft like
Sailrocket.

As a side note: I have spent time on Vestas wind turbine blades (rappelling
down them using ropes to inspect the fiberglass) and they are an amazing feat
of engineering. You can't really appreciate their strength to weight ratio
until you have been on the tip of a 40 meter blade.

~~~
sounds
Just curious, I frequently see turbine blades for wind installations hauled on
a sort of "trailer" down the interstate. I put "trailer" in quotes because
it's really two frames around the blade, one at the front and one at the rear.
The strength of the trailer seems to be the blade. I'm always surprised when I
see it, thinking surely that can't be safe? (But carbon fiber can be
completely safe.)

Do you know about these? Would it be a good guess to say the blades are Vestas
blades? Can you tell me more about their strength-to-weight?

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dhughes
There are some in my town too you see giant tubes and blades heading out of
town towards the testing facility, 90 metre monsters.

It's funny this article is about wind I guess that's the point him being an
engineer for Vestas. Here on the island I live on we often get windsurfers who
come here because it's so windy.

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ChuckMcM
As a sailor I cannot imagine what those speeds must feel like. I got a chance
to sail a Hobie 16 on San Francisco Bay and it was pretty amazing to see how
fast it could go and I doubt we even hit 20 knots. Nicely done Larsen, nicely
done.

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jfoucher
Wow this actually almost brought tears to my eye :D

These guys have been at it for so long it is hugely deserved !

listen to his voice on the record's video
(<http://www.youtube.com/watch?v=wnjyusAgk8I> ) I think it helps get a sense
of it must be like sailing at that kind of speed

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hencq
Yeah it's pretty amazing. I wonder if his comparison to the X-1 is right. That
now the barrier has been broken, we'll see even faster designs relatively
rapidly. The margin by which he went over it seems to suggest it might. I also
liked the part about the models disagreeing because there was no actual
experimental data. It's easy to forget that sometimes today when computer
models seem to explain everything.

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relix
If I interpret what I read correctly - that because of the new design there's
no turning moment, and that hence there's no point at which the boat would
capsize, and all energy is thus put into forward motion, that you can just put
a bigger sail/wing on it to get more energy from the wind, and go even faster,
linearly with the size of the wing (minus some extra weight overhead).
Basically, if true and I'm not missing something, the only limit to the speed
has become material strength and weight.

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jaggederest
Pretty amazing stuff. Reminds me a lot about reading about the Pegasus class
hydrofoils, reputed to have been capable of 55-60 knots

<http://en.wikipedia.org/wiki/Pegasus_class_hydrofoil>

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jacquesm
For an idea of the kind of challenges they faced in the past:

<http://www.youtube.com/watch?v=8Ow8QbXhZJU>

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martinced
It's obviously inspired by a much older design, the "Hydroptere". Give credits
where it's due ffs!

Which TFA doesn't mention at all.

Here's a Youtube video comparing the two:

[http://www.youtube.com/watch?gl=BE&v=qzkulFGa4Mc](http://www.youtube.com/watch?gl=BE&v=qzkulFGa4Mc)

These kinds of boat, which are lifting out of water as they gain speed, are
fast but can't really be used in real oceans unless the weather is nice
because they can't handle big waves.

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jfoucher
Sailrocket is no way inspired by Hydroptère, and in fact one might argue that
they could not be more different:

Hydroptere works by countering the heeling moment caused by the force on it's
sails and foils, with, basically, it's weight (it's weight times the distance
between the center of gravity and the leeward foil) whereas Sailrocket works
by having NO heeling moment and actually somewhat of a negative one, as the
leeward hull can be seen lifting clear out of the water at speed.

Hydroptere lifts out of the water by using foils, which are basically wings
that work in water (at the air/water interface actually, which causes a host
of problems) whereas Sailrocket skims along on planing surfaces, just like a
powerboat or a windsurf.

Sailrocket, as indicated in the article, owes a lot to Bernard Smith ( seminal
work : [http://www.amazon.com/Sailloons-Fliptackers-High-Speed-
Saili...](http://www.amazon.com/Sailloons-Fliptackers-High-Speed-Sailing-
Library/dp/0930403657) )

Finally, Hydroptere works on both tacks (wind coming from either side) where
Sailrocket only works on one tack. Some fascinating workarounds for this
issues have already been worked out by Bernard Smith by the way.

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bigiain
+1.

Look carefully at this picture from the article:

[http://www.wired.com/images_blogs/autopia/2013/01/ff_superca...](http://www.wired.com/images_blogs/autopia/2013/01/ff_supercavitation5_large.jpg)

Check out the orientation of the "bridle lines" from either end of the wing,
and the keel. When I saw that, it all went "click" in my head. This is just a
wing tethered to the keel - like a kite, or a paragliger - the hull/fuselage
and the spar and pods/floats are all just "unnecessary" bits, only used to
hold the wing and keel in the required orientation to get up to operating
speed. (I wonder if someone will build a version of this which jettisons all
of the boat-like structure when it gets the keel and wing up to the speed
needed?)

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jfoucher
AFAIK there is one project that tries to remove all "unnecessary" bits,
although it's just a model:
[http://www.youtube.com/watch?v=1tEw_mlUh7g&feature=playe...](http://www.youtube.com/watch?v=1tEw_mlUh7g&feature=player_detailpage#t=231s)

Just a kite tied to a "water kite"

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bigiain
Cool! Thanks for that link.

That's very close to the ideas floating round in my head right now. Something
very similar to that, a super efficient "kite" (think more like the SailRocket
sail or a glider wing), "tethered" underwater using this 50+knot cavitation
tolerant foil technology. I'm guessing it'd need a fair bit of "stuff" to get
it up to the speed where the wing and foil start to operate effectively, wich
might either be jettison-able floats/spars, or perhaps some technique where it
gets launched/towed up to speed - kind of like how big wave surfers use jetski
tow-ins to get on to big waves at speed - I wonder what the world record rules
would say about a 70+knot "sailboat" that need to be towed up to 50_knots to
work at all?

