Hydrofoil quad

[dspring...@googlemail.com]

I've seen hydrofoil singles but is this a hydrofoil quad??
@tgeraedts: Is it still called sculling when your are flying? Massive effort by @tudelft RISE sport innovation @ProteusEretes http://t.co/DKPJbE11jK

[marko....@gmail.com]

Impressive, no sliding riggers either. I wonder if there is a video anywhere?

Should have used fluid bow mounted riggers to help of course since as we know they lift the boat ;)

[Henning Lippke]

Am 18.08.2015 um 22:19 schrieb marko....@gmail.com:
> Impressive, no sliding riggers either. I wonder if there is a video anywhere?

It has sliding riggers / fixed seats. Check out the facebook page, there
are photos.

https://www.facebook.com/RISEdelft/photos/pb.218254375013673.-2207520000.1439931860./425368930968882/?type=1&theater

Still impressive.

[carl]

If you'd like to see the hydrofoil system, which seems to be either
missing or hidden in that FB photo, go here:
https://www.facebook.com/RISEdelft/photos/a.219377631568014.1073741828.218254375013673/339892322849877/?type=3&theater

From the small amount visible here, it is a pair of relatively standard
T-foils:
https://www.facebook.com/RISEdelft/photos/a.219377631568014.1073741828.218254375013673/299507336888376/?type=3&theater
Perhaps with some type of surface sensor to adjust AoA or camber for
ride height?

But they're not using the foil shape shown here:
https://www.facebook.com/RISEdelft/photos/a.219377631568014.1073741828.218254375013673/271396366366140/?type=3&theater

Question: are the sliding riggers really necessary or just a
complication? The relative movement of the crew's CofG is rather small
in relation to the length of a 4x. One of our (Dutch) clients has
fitted a hydrofoil system, with similar cambered foil section, onto one
our sliding seat singles & it flies pretty well.

It's great to see people willing to break out of the narrowly & mentally
narrowing conventional format into which rowing has locked itself. I'd
like to see special events for "alternative" rowing shells, under which
heading I'd include not just foiling shells but 100m races for
conventional shells too, and other suggestions welcome. Rowing
equipment evolved through the work of experimenters, unconstrained by
arbitrary rules concocted by a bunch of people who neither build nor
design shells. It would be good for rowing to evolve some more.

Cheers -
Carl

--
Carl Douglas Racing Shells -
Fine Small-Boats/AeRoWing Low-drag Riggers/Advanced Accessories
Write: Harris Boatyard, Laleham Reach, Chertsey KT16 8RP, UK
Find: tinyurl.com/2tqujf
Email: ca...@carldouglasrowing.com Tel: +44(0)1932-570946 Fax: -563682
URLs: carldouglasrowing.com & now on Facebook @ CarlDouglasRacingShells

[David Cormack]

Out of interest Carl, a rowing boat, completely unconstrained rules, what would that entail?

Maybe a few rules? the rower must face the stern and propel the boat a rowing action.

Hydrofoils? Flywheels? What would there be?

[dspring...@googlemail.com]

I've heard rumours that just such a race series is being considered....sprint distance, no regulations on boats....fingers crossed it comes to fruition.

[carl]

Good questions indeed, David.

My answer is that I don't know. Yes, I do have a few ideas of my own,
including the 2 which I suggested, but I am very sure there are people
out there with great ideas who'd be willing to experiment at their own
cost with a view to extending the scope & attraction of our sport.

I find it strange, given the technological opportunities now available
(and I mean technology in its all-embracing sense, not in today's narrow
definition of "anything to do with computing"), that rowers are so
ignorant of real technology that they won't even undertake comparative
testing of existing equipment. I'm sure there's a safe place to play
for those who see "technology" in a paint colour, in a branding exercise
& in celebrity acclaim, but I'm sad that rowing is so shy of anything
which might prove radical & game-changing.

Other sports have been bold enough to experiment. Sailing would be good
example: if we consider only hydrofoiling, consider the huge advances
made at one end of the scale in current America's Cup boats &, at the
other, the foiling Moths.

I'm also surprised, just for instance, by the eagerness of rowers to
believe that just changing materials somehow changes conventional shell
performance, & to unquestioningly swallow a suite of banal explanations
of what moves boats, with no sport-wide attempt to correct Victorian era
misconceptions - & instead we have the new-age numpties cheerfully
telling crews to wait to feel "the lift" on their blades before pulling.

So, returning to your question, let's have suggestions for what rowers
would like to see change & develop.

[Henry Law]

On 19/08/15 09:05, David Cormack wrote:
> rowing boat, completely unconstrained rules, what would that entail?

Categories for "clean" and "drugged-up" crews?

--

Henry Law Manchester, England

[Kit Davies]

One feature that has been discussed here in the past are gates mounted
on arms forward of and pivoting around the pin. I'd be interested to see
what the outcomes would be, both positive and negative.

Kit

[marko....@gmail.com]

On Tuesday, 18 August 2015 23:48:40 UTC+1, carl wrote:

> It's great to see people willing to break out of the narrowly & mentally
> narrowing conventional format into which rowing has locked itself. I'd
> like to see special events for "alternative" rowing shells, under which
> heading I'd include not just foiling shells but 100m races for
> conventional shells too, and other suggestions welcome. Rowing
> equipment evolved through the work of experimenters, unconstrained by
> arbitrary rules concocted by a bunch of people who neither build nor
> design shells. It would be good for rowing to evolve some more.

Sailing has been good at this with development classes being places for builders and designers to try out new things with a varying measures of restriction to make sure costs don't go mad. The Austrian systems is good: they set a value and anyone is able to offer that value for someone else's boat and they have to agree to sell. The moth fleet are now almost entirely foiling and some formula cat classes are trying. The International 14 fleet have T-foils on the rudders for lift with various ideas as to why this is faster (I have always wondered if this would help pitching in rowing.)

What you suggest might be more half way to Weymouth Speed Week where people turn up with all sorts of sailing contraptions to see what speed they can clock rather than race.

[Henry Law]

On 19/08/15 13:00, marko....@gmail.com wrote:
> The moth fleet are now almost entirely foiling and some formula cat classes are trying.

How exciting; but the Wikipedia entry makes an interesting point:

"Originally a cheap home built sailing boat designed to plane, now it is
an expensive largely commercially produced boat designed to hydroplane
on foils ..."

[Kit Davies]

On 18/08/2015 23:48, carl wrote:
> Question: are the sliding riggers really necessary or just a
> complication? The relative movement of the crew's CofG is rather small
> in relation to the length of a 4x. One of our (Dutch) clients has
> fitted a hydrofoil system, with similar cambered foil section, onto one
> our sliding seat singles & it flies pretty well.

Does the length of the shell make a difference?

I was under the impression that the problem lies in the oscillations in
boat speed, and that that depends on the relative masses of boat & crew?
Would that not be the same (or at least similar) between small and large
boats?

Kit

[2potsin...@gmail.com]

Interesting idea there. A practical question - how does the rower accommodate the change in seat/rigging height off the water so as to keep the oar blades in the water when the foil starts to lift the boat?

[John Greenly]

On Wednesday, August 19, 2015 at 5:41:09 AM UTC-4, carl wrote:

It would be good for rowing to evolve some more.

Yes, that's a fine challenge! Looking at our basic constraint of moving oars through the water to propel the boat, I always find myself thinking about the fact that we, the fastest human-propelled boats over significant distances, really don't use our blades the right way at all. The Inuit, the Vikings, in fact all old-fashioned self-propellers, used long narrow blades oriented nearly horizontally and with a lot of vertical motion in the water to make them efficient foils all through the stroke, as we have often discussed in the past. Modern kayakers with "wing" paddles work very efficiently as well, but with a different stroke geometry, a nearly vertical foil moved horizontally.

Our big advantage over all those is that we use our leg power properly. But as we do it now, the resulting stroke geometry means that we shove our blades through the water mostly horizontally with a ridiculously bad blade aspect ratio, rapidly and widely varying angle of attack, and terrible lift efficiency through almost all of the stroke. Can we somehow fundamentally change our blade and stroke geometry so that oars move in such a way as to present high aspect ratio to the flow and generate good lift efficiency all through the stroke?

--John

[jonathan...@gmail.com]

Oars have pretty high efficiency, higher even than propellers, and have the advantage over paddles of using leverage to increase the gearing.

There seems to be more room for improvement on the drag side. Even short of hydrofoils, a non-smooth surface seems promising: http://www.natureworldnews.com/articles/5697/20140118/researchers-create-rough-surfaces-that-reduce-drag.htm

[carl]

On 19/08/2015 17:25, jonathan...@gmail.com wrote:
> Oars have pretty high efficiency, higher even than propellers, and have the advantage over paddles of using leverage to increase the gearing.
>
> There seems to be more room for improvement on the drag side. Even short of hydrofoils, a non-smooth surface seems promising: http://www.natureworldnews.com/articles/5697/20140118/researchers-create-rough-surfaces-that-reduce-drag.htm
>

What that report appears to describe is already known, & of long
standing, as Riblets - by 3M. Available in adhesive tape form, it is
applied with its fine surface grooves aligned with the local flow
directions.

Riblets work by suppressing "bursts" of localised mini-vortices from a
hull, wing or foil surface. The effect of those bursts is otherwise to
trip an existing laminar boundary layer & convert it from laminar to
turbulent, whereupon the rate of energy exchange between the surface &
the bulk fluid is much increased, resulting in higher surface drag/skin
friction.

I'm unsure to what extent Riblets could be used on oarblades, but FISA
has long since banned their use on hulls.

[jonathan...@gmail.com]

On Wednesday, August 19, 2015 at 10:43:03 AM UTC-7, carl wrote:
>
> What that report appears to describe is already known, & of long
> standing, as Riblets - by 3M. Available in adhesive tape form, it is
> applied with its fine surface grooves aligned with the local flow
> directions.

I see another study from 1987 reported a 2% reduction in drag when testing Riblets with rowing. One problem they ran into was the effect of the Riblets would vary from day to day. The more recent results also add in a superhydrophobic material that creates an air cushion on the Riblets. That would increase the effect and perhaps reduce fouling of the material.

For just 2% it's probably a good idea to ban such materials. The question is what improvement would be enough to make it worth it to recreational rowers for the extra expense. The videos on youtube of hydrofoil singles makes it look those make rowing more difficult, so it would probably not be appealing to recreational rowers. On the other hand, special materials would not change much, apart from creating more sense of speed.

[marko....@gmail.com]

On Wednesday, 19 August 2015 21:19:06 UTC+1, jonathan...@gmail.com wrote:
The videos on youtube of hydrofoil singles makes it look those make rowing more difficult, so it would probably not be appealing to recreational rowers.

It looks like high pressure/rating is required to be maintained otherwise the boat sinks at the catch (even with sliding riggers). Just dealing with the varying high off the water must be difficult to adjust to too.

[Valgozi]

Video sneak peak of it on youtube is available now - https://youtu.be/6Mb_U-ne89A

For it to work optimally would the rigger heights need raise and lower?

[Kit Davies]

On 18/08/2015 20:57, dspring...@googlemail.com wrote:
> I've seen hydrofoil singles but is this a hydrofoil quad??
> @tgeraedts: Is it still called sculling when your are flying? Massive effort by @tudelft RISE sport innovation @ProteusEretes http://t.co/DKPJbE11jK
>

Now with added video:

https://www.youtube.com/watch?v=6Mb_U-ne89A

Kit

[Valgozi]

On Tuesday, August 18, 2015 at 8:57:08 PM UTC+1, Daniel Spring wrote:
> I've seen hydrofoil singles but is this a hydrofoil quad??
> @tgeraedts: Is it still called sculling when your are flying? Massive effort by @tudelft RISE sport innovation @ProteusEretes http://t.co/DKPJbE11jK

This design on the Dyson Awards website of a Quad is quite interesting.

http://www.jamesdysonaward.org/projects/quad-scull-hydrofoils/

It looks to retrofit Hydrofoils on to a rowing boat with reinforcement of the washboard.

[Kit Davies]

Why are they looking to lift the boat at the gates? That feels like the
worst place of all. At a minimum, lift the riggers close to the
gunwales, but better, lift the hull from the bottom, surely?

Kit

[Valgozi]

It is probably one of the worst places, I assume it is so they can be fitted to any rowing shell, without changing the hull. Although it would need strengthening at the washboard. The riggers would have to be very strong if it had the weight of the crew and boat suspended from the ends.

It seems a concept, I wonder if it will ever get to a prototype stage.

[Kit Davies]

Additionally, this would only really work on fixed rigger boats, ie one
with the normal fluctuations in hull speed. So the boat will be rising
and falling by 6+ inches on every stroke, if it ever flies at all.

It makes me wonder about the validity of the Dyson Awards, TBH ?!

Kit

[andymck...@gmail.com]

So mash together the spirit of Walter Bradford Woodgate, a multi stage rocket and the Disco Volante from Thunderball and we have my 'LightFoil', the ultimate head race winning boat!

Rowing up to the start it looks like a normal 8, but the bow 4 seats and riggers are actually attached to a lightweight carbon fibre spine and not actually connected to the hull by anything other than gravity. As you wind up to full power, the bow 4 seats and rowers rise up on the foils, lifting the rowers clear of the hull, with its redundant henchmen style stern 4 rowers and cox left to navigate on their own. The bow rowers, un-encumbered by any thing as old fashioned as a hull, power to victory.

I admit that the Lightfoil may not meet FISA buoyancy standards, but it is un-swampable and totally self draining - so no pumps required.

Andy