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Re: Foiling M20?! [Re: Rolf_Nilsen] #185781
07/22/09 04:57 AM
07/22/09 04:57 AM
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Melbourne, Australia
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Originally Posted by Rolf_Nilsen
Originally Posted by taipanfc


In August last year on Sydney harbour, the moth beat the all the A-Cats in 3 out of 4 races. The first placed A was Steve Brewin who is a quite handy sailor.


Do you have a link to the event? Not going to nit-pick details but I would like to see it confirmed that the Moth is faster around the course than high-perf cats, when comparing apples to apples.


I don't think the reults are available on line any more but I was there as a spectator that year (as I just sold my Cap).

The Moth guy was one of the very top Moth sailors and as we know, Stevie can sail an A OK.

The conditions were enough for foiling each race with the second day from memory being fresh. It was a typical winter regatta on Sydney Harbour and the wind was very shifty. Stevie was edged out by the moth for both handicap and line houners in this regatta. When I discussed with him, he said he was supprised with the pace of the moth and said he was a little quicker in this regatta (because he won). Boat for boat I believe they are very close, perhaps equal in these conditions. The shifty nature and better tactical decisions may have also lead to the Moth winning the regatta, however I think you will find they are about on par.

The previous years, the Moths did not even come close to the cats in any race however the conditions ranged from non foiling on one day and blowing on the next with holes of no breeze...... Typical Winter Sydney Harbour. The last year I raced, only an 18 beat us for line hounours in one race (where we started late and gave him a 1/2 leg lead on the first upwind. Every other race we took line honours by 3 to 5 mins from an 18 with all other boats not even close.

TaipanFC, when he raced at our club was a very passionate (and very quick) Taipan sailor. In Singapore he has both an A Class and a Moth so will give you a very fair analasis of both boats.


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Re: Foiling M20?! [Re: Wouter] #185783
07/22/09 05:21 AM
07/22/09 05:21 AM
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Originally Posted by Wouter
To all (and not specifically to James)

Just for the record.

I do think the moths are very exiting sail craft and really respect the guys that developped the full foiling moth into a viable alternative to the non-foiling moth.

The fact I have serious doubts about a full foiling catamaran doesn't mean I look negatively upon the moth themselves.

I do believe that partial foiling like the ORMA tris and the John de Vries special are doing is viable for large cats. This involves bruce foils (or curved foils) and only lift the boat up by say 60% at their absolute full speed.

The reason for this are the control issues that arise when more of the boat is lifted and a positive feedback is created between the rise of the hull and increasing the angle of incidence of the foil which in turn ... well the famous foiling jump.

I also have a question for James. Do you feel the VYC rating of 84 is correct for the Moth, considering it is an average that is to be taken over all windconditions ?


Wouter


I don't think ratings will work well for Moths as their performance is not consistent for all conditions. When not foiling then I am as quick as a Laser if I am lucky and they rate over 100 in VYC. When foiling in a wind range of 8-12 then no cats can get close as you are still powering up. 20+ is survival mode in the Moth (at least for me) and lots of issues with just keeping the mast pointed upright whilst the boat is going like a scalded cat (awesome fun though and scary). If you don't have your foils set up correctly for lift then prepared to be lightning fast with a massive crash at any moment.

As for foils on cats. Will happen. I don't think the current approaches have worked or were the best ideas, but I don't know what the alternative will be or should be. Someone I am sure will get the lightbulb idea and make it work.

Drag is the big issue, but also auto-adjustment on the fly too. The amount of time I spend adjusting and re-adjusting the foils is quite significant. Really set it up for the conditions, wind and wave. All down to the gearing and how it reacts. So for a cat with 2 hulls this could become a fine art.

Re: Foiling M20?! [Re: taipanfc] #185784
07/22/09 05:47 AM
07/22/09 05:47 AM
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Thanks for answering my question James,

Actually about 2 year ago I propose the control of a foiling Moth as a 2nd year design assignment for control systems students at my university. I thought it was an excellent concept vehicle to have them try to design a proper controller to ease the load of the sailor. I feel that relatively simple control concepts can go a very long way in stabilizing the Moth while sailing

The problem with a catamarn is of course that it will have two foils (each in one hull) and that leads to a multivariable control situation where control actions on one foil setup will have a noticable effect (disturbance) on the other foil setup. This is typically a difficult control problem to solve.

I feel hydroptere is on the right track with regard to a viable full foiling multihull, but I don't think it is a very good windward/leeward racer. Its bruce foils provide a level of automatic control that you just don't have with T-foils. That is one reason why foiling motorboats often used the V-foil setup.

I am however convinced that the path to succesful foiling requires the assistance of a skilled control systems engineer and that had been lacking up to now. The rave was apparently hard to control and only the Hobie Tirfoiler seem to have gotten the T-foil setup working right on a multi hull. I think that was mostly due to the way they had implemented the control setup.

But I wish everyone who tries the best of luck.

Wouter


Wouter Hijink
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Re: Foiling M20?! [Re: Wouter] #185822
07/22/09 11:54 AM
07/22/09 11:54 AM
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Asuncion, Paraguay
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Originally Posted by Wouter



The problem with a catamarn is of course that it will have two foils (each in one hull) and that leads to a multivariable control situation where control actions on one foil setup will have a noticable effect (disturbance) on the other foil setup. This is typically a difficult control problem to solve.


Alinghi seems to be raising its windward foil all the time. It requires crew work, but eliminates this problem.

Quote


I am however convinced that the path to succesful foiling requires the assistance of a skilled control systems engineer and that had been lacking up to now.



Agreed. The ORMA 60s have no control system, though. I think there is a good possibility that symetrical section T or L foiled rudders combined with S foils would be a self-stabilized setup.


Luiz
Re: Foiling M20?! [Re: Luiz] #185831
07/22/09 01:30 PM
07/22/09 01:30 PM
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Quote

I think there is a good possibility that symetrical section T or L foiled rudders combined with S foils would be a self-stabilized setup.



Yes, but someone with skills in this area still has to design it to the proper dimensions for it to work well.

Wouter



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Re: Foiling M20?! [Re: Wouter] #185832
07/22/09 01:33 PM
07/22/09 01:33 PM
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Portland, Maine
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Sounds like you just volunteered.

:P

Re: Foiling M20?! [Re: Wouter] #185859
07/22/09 05:29 PM
07/22/09 05:29 PM
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Asuncion, Paraguay
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Originally Posted by Wouter

Quote

I think there is a good possibility that symetrical section T or L foiled rudders combined with S foils would be a self-stabilized setup.

Yes, but someone with skills in this area still has to design it to the proper dimensions for it to work well.


Or add flaps to the rudder foils in a prototype and keep prototyping and testing until the flaps are no longer necessary.


Luiz
Re: Foiling M20?! [Re: Rolf_Nilsen] #185864
07/22/09 05:52 PM
07/22/09 05:52 PM
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France
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Originally Posted by Rolf_Nilsen
Not going to nit-pick details but I would like to see it confirmed that the Moth is faster around the course than high-perf cats, when comparing apples to apples.
Wednesday club races tonight at DWSC: 10 knots of wind or so. A varied set of boats around a triangle course. After an hour racing:

After 4 laps a Hurricane 5.9 finished first, I was further behind by 3/4 minutes, two other F16 and another hurricane finished in the next 4 minutes behind me, a well driven solo Dart 18 shortly behind them. The moth, a bladerunner, finished right behind me, before the other F16. But the bladerunner lapped *everyone* but the first two cats.

He was first to the windward mark by a mile, by the C mark when I rounded the B mark (I was second at that point) and then just gone.

So in one hour, the moth did 5 laps, we fast cats did 4, the asymetrics where somewhat behind us but on 4 laps as well and the slow boats (laser and all) did 3 laps.

Foiling: way faster.

We don't have the results yet, but they will be posted there hopefully sometimes tomorrow.

Re: Foiling M20?! [Re: pepin] #185920
07/23/09 12:59 AM
07/23/09 12:59 AM
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Yeah but what is the rating for a Bladerider compared to a 110(?)kg F16? It only weights 30kg right?

Re: Foiling M20?! [Re: Tony_F18] #185923
07/23/09 01:32 AM
07/23/09 01:32 AM
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West coast of Norway
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I was mostly interested in pure speed around the course and it sounds like it is faster when it can foil. Assuming sailors are competent of course.

Re: Foiling M20?! [Re: Tony_F18] #185924
07/23/09 01:34 AM
07/23/09 01:34 AM
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Originally Posted by Tony_F18
Yeah but what is the rating for a Bladerider compared to a 110(?)kg F16? It only weights 30kg right?


Probably more like mid-30s. The home built ones can be sub-30, but you find those guys spending each evening repairing the boat.

Only has an 8 sq m sail. F16 has 13 sq m or so mainsail, 17 sq m spinnaker, plus a jib too... I am sure Wouter has the exact numbers to divulge here.

Re: Foiling M20?! [Re: Rolf_Nilsen] #185925
07/23/09 01:37 AM
07/23/09 01:37 AM
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Originally Posted by Rolf_Nilsen
I was mostly interested in pure speed around the course and it sounds like it is faster when it can foil. Assuming sailors are competent of course.


Haha, big understatement about competency. I have capsized more in the first 3 months of owning a Moth than I did in my whole 20 year sailing career combined. I think I capsized 5 times or more just getting out of the marina the first day and that was a distance of 100m.

Re: Foiling M20?! [Re: ThunderMuffin] #185928
07/23/09 03:16 AM
07/23/09 03:16 AM
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Quote

Sounds like you just volunteered.



Good point !

But first I have to finish some other projects I'm afraid.

Worth considering though !

Wouter


Wouter Hijink
Formula 16 NED 243 (one-off; homebuild)
The Netherlands
Re: Foiling M20?! [Re: Tony_F18] #185929
07/23/09 03:23 AM
07/23/09 03:23 AM
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Rating Moth

If you punch in the moth numbers in the Texel rating calculator then you get a rating of 130 (=about the same as a Hobie 14); but of course this calculator assumes that the hull is fully in the water.

When converting the VYC rating to Texel you get 118 (= on a par with a Hobie 16)

Wouter


Wouter Hijink
Formula 16 NED 243 (one-off; homebuild)
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Re: Foiling M20?! [Re: Wouter] #185935
07/23/09 07:08 AM
07/23/09 07:08 AM
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Originally Posted by Wouter

Rating Moth

If you punch in the moth numbers in the Texel rating calculator then you get a rating of 130 (=about the same as a Hobie 14); but of course this calculator assumes that the hull is fully in the water.

When converting the VYC rating to Texel you get 118 (= on a par with a Hobie 16)

Wouter


Depending on LOCATION and also Sailor Skill.

PY rating (NOT SCHRS) is nywhere between 900 (slow) and 650 (Fast). For comparison

F18 is about 691, F16 is similar and the Tornado is 650.

Problem in the UK is that we have very few (if any) Tornado's that club race against the moth, and no really decent teams doing this limit club racing.

Is the Moth quicker than a Tornado around the course? No is Sub foiling for the Moth. Similr in ideal MOTH foiling conditions and when howling the T will win.

Still very good for an 8 foot boat!!!


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Re: Foiling M20?! [Re: scooby_simon] #185941
07/23/09 07:31 AM
07/23/09 07:31 AM
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That's the first time we had a Moth on our Wednesday race, and unfortunately our only active Tornado team was not on the water. They are good, they finished second at the last national if I remember correctly. And they usually lap everyone on our relatively short courses.

Hopefully, one of these days the two of them are going to be on the water at the same time with a decent amount of wind...

Re: Foiling M20?! [Re: pepin] #185956
07/23/09 10:17 AM
07/23/09 10:17 AM
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I don't see what difference it makes as I never expect to see the two (cats vs. moths) on the same starting line, except maybe a fun club type race.

Each type (cat vs. foiling moth) has it's own "perfect conditions" for going maximum speed, I doubt it is the same for both boats, so you are still comparing apples to oranges. Which ever boat the prevailing conditions favor will do better, obviously.


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Re: Foiling M20?! [Re: Wouter] #185961
07/23/09 10:48 AM
07/23/09 10:48 AM
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Originally Posted by Wouter

Actually about 2 year ago I propose the control of a foiling Moth as a 2nd year design assignment for control systems students at my university. I thought it was an excellent concept vehicle to have them try to design a proper controller to ease the load of the sailor. I feel that relatively simple control concepts can go a very long way in stabilizing the Moth while sailing


Any results to actually divulge from this? Control systems for the Moth are still being actively developed and will do so for a while to come.

Re: Foiling M20?! [Re: taipanfc] #185971
07/23/09 12:54 PM
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As with so many things at the university it disappeared into that big black hole.

They did put a PHD student on the idea to see if he could develop it into a viable assignment. He contacted my once, I gave him a very good head start on nearly everything and then he disappeared of the face of the world. I dare say that he did the motions in order to not upset the professor who gave him the assignment but other then that deep sixed it.


May be contact me in 6 months or so and see if I'm still tickled by it ? Till then I have my hands full in getting the final report on my other research accepted.

Wouter

Last edited by Wouter; 07/23/09 12:55 PM.

Wouter Hijink
Formula 16 NED 243 (one-off; homebuild)
The Netherlands
Re: Foiling M20?! [Re: pepin] #185986
07/23/09 03:07 PM
07/23/09 03:07 PM
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Originally Posted by pepin
That's the first time we had a Moth on our Wednesday race, and unfortunately our only active Tornado team was not on the water. They are good, they finished second at the last national if I remember correctly. And they usually lap everyone on our relatively short courses.

Hopefully, one of these days the two of them are going to be on the water at the same time with a decent amount of wind...


I have to concur with Pepin, the Mothie simply blitzed us last night, so much so I want one but being a biggie fat arsed sort of bloke, it aint going to be a Moth. Seriously though I was impressed with the speed and handling of the Moth, the upwind was not as much as a problem as I thought it would be for him, really dramatic to watch as he lapped me, the really deep starting angle ( speed ) and then the really arched curve onto the remainder of the tack ( building apparant wind ).

In the right wind conditions ( to be fair we couldn't really wire properly last night with about 8 knots to 12 knots at times wind ) the mothies are going to blitz some race records. I think with another year or two of development, they are going to pretty special.

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