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Moth Developement

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hey guys

so i have been thinking about what people can actually do to make moths faster

and to be honest, i cant think of too many more ways that moths can be improved a whole lot

everyone is spending so much time fixing wind drag, which in the scheme of things is only making the tinyest of differences

from what i heard about the Garda worlds, the decksweeper main and fairing was not the best and just got in the way, but it looks like the sail is of good use (outteridge is using it at the moment)

i'm not too sure how much better the latest foils are nowadays, but i've heard that there is not too much that is improving

and i don't believe the hulls make a whole lot of difference when they are up and going

so my question is, hat are people working on, or what could people work on to make the moth a faster boat?

and also, is match 2 being overtaken by exocets now? or do the better sailors just like to look special?

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Speedwise most foils of all latest boats are very close. Only Mach2s do not have a good big foil (so people buy the lanulfi gp or will buy the new damic bigfoil), other than that it will be all small incremental changes imho. You cannot get stiff foils much thinner than what we are using now. Surface Finishing matters, but that is just a matters of hours put into painting and sanding, not of real developement

Key in the hull is stiffness and control system. uk boats are stiffer than mach2s (but they are heavier) and this helps, all control system are very similar now, except the cams system some aussie have, which may be a good developement.

There is a lot of rig developement right now. The balance between span, capsizing moment, sail shape, usability and eventual endplating (so interaction with hull ) is hard to get right. The 2017 rules which allow 10cm more span could also play a role in defining where the right compromise is.

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What's the feel in the class on considering an electronic ride height system? I realize currently it wouldn't be allowed in the rules, but it could have a significant impact on the boat's performance not to mention making it easier to sail. 

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The feeling in much of the class is that the boats are getting way too expensive. Since the huge fleet at the Malcesine WC last year most regattas have suffered from very poor numbers. There were less Australian boats in the Wangi Nationals this month than there were in Malcesine last July. The entry numbers for the Bermuda WC are even poorer and its on in a few weeks. 

Adding something new which will increase costs again would be very unpopular. Changing rules would open up another design race with associated development costs. I do not see not happenning.

There are several new boats in the pipeline and some new foils. These designers are hoping for minor improvements on existing performance.

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1 hour ago, Phil S said:

The feeling in much of the class is that the boats are getting way too expensive. Since the huge fleet at the Malcesine WC last year most regattas have suffered from very poor numbers. There were less Australian boats in the Wangi Nationals this month than there were in Malcesine last July. The entry numbers for the Bermuda WC are even poorer and its on in a few weeks. 

Adding something new which will increase costs again would be very unpopular. Changing rules would open up another design race with associated development costs. I do not see not happenning.

There are several new boats in the pipeline and some new foils. These designers are hoping for minor improvements on existing performance.

Hi Phil,

If this is the case would the class be open, there I said it, to reducing it's development of foils and rigs, and to limiting the #s of foils and rigs that they are allowed to use at a regatta (maybe just 1 of each)?

Having classes that are expensive is not good for the class nor the sport of sailing. 

I'm sure the moth class would still move forward with these limitations.

Fish

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5 hours ago, vox said:

What's the feel in the class on considering an electronic ride height system? I realize currently it wouldn't be allowed in the rules, but it could have a significant impact on the boat's performance not to mention making it easier to sail. 

I don't think an electronic height system will have much benefit at all.

In flat water (say up to 0.3m chop) wands do an excellent job, you can pretty much just ignore waves. It's hard to see an electronic system doing any better so zero performance gain there. Once the water get's lumpy (say more than 0.5m chop), it's a very much more complex situation and sailor skill is the key to speed, especially if it's chop plus swell. An electronic system would need to balance changes in the distance between the boat and surface, then work out whether that's due to pitch, waves or boat handling, then take into consideration inertia and momentum in any wave–associated flap adjustment, and whether any adjustment was needed at all. It's not just a matter of keeping the boat at a specific distance above the local water surface, but anticipating what the surface is going to do and where the boat needs to be in a few moments time.

Waves do not form a nice sinusoidal shape, they vary greatly in size and are affected by currents, boat wakes, rebound from shorelines, bending, interference, etc. So an electronic system would need to be very, very good to beat the current wand system with a skillful sailor.

If the intention is to make the boats easier to sail, I don't think an electronic system will do that either. Better just to not sail in unmanageable conditions.

But the bottom line is always that someone needs to invent one, see how it goes against other boats and if the class thinks it's a good thing, maybe it will get the nod. But probably not.

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1. The class voted in Japan 2016 for a two equipment rule, two sets of foils, two masts, two sails, and this was applied for the 2017 Malcesine WC. There has been discussion amoungst moth sailors that a one equipment rule might be better but there is no consensus yet. Another option raised is to limit foils to one set but allow two masts and sails. More discussion is happenning, but there are no formal proposals at present.

2. Someone in UK developped an electronic control system on a moth like foiler several years ago. Videos show it working OK in at least flatish water. No idea if it worked in waves. Apparently no one was convinced that it had any functional or cost advantages over the mechanical wand as it was not put into production nor used on any of the new OD foiler monohuls.

While the Mach2 wand linkage system uses a big number of specially machined parts, many home builders manage with quite simple systems built from parts worth less than $100. The principal is not complex, good design is usually the simplest.

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Phil S,

  In the A-Cat class there is a 1 equipment rule that seems to work quite well. Frankly I am quite surprised at the costs in the Moth class, for example a Rocket Main foil and rudder foil package cost ~50% more than a pair of daggerboards and pair of rudders in the A-Cat from one of the builders. On par with the other class builder I believe, but we are talking two sets of foils! My point here is I think the class would be well supported by finding a lower cost builder/product, i.e a baseline Mach 2 that is still competitive but not crazy in terms of rig or foil development at a lower price point. Just my thoughts as an outsider looking in, the A is doing well in the U.S and globally at the moment as the boats are getting easier to foil, handle chop reasonably well, and can still be sailed in 'classic' or 'safe mode' in bigger breeze and chop or in light air floating mode. Anything the Moth class can do to cover those ends and put together quality events will drive up participation.

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Moth foils cannot significantly cheaper. They take a loooot of man hours to build and to finish to a decent standard.  They have t-joints, flaps, control systems embedded in them, etc. And everything on them has a significant impact on perfomance; so there is no way that a "cheap" builder will reign the moth foil market. We are a developement class and people will always want to get the fastest foils.

There is definitely a point in discussing a 1 foil per regatta restriction. After the chat in Garda Luca (imca pres) was keen on a public consultation (not necessarily a vote) to see where most of the guys want to go. I haven't heard from him in the past few weeks, so I don't know if something is happening now, or if that discussion will be directly held in the class meeting in Bermuda.

I just bought 2 mainfoils for my latest boat, and spent like 20 hours to finish them, so I want to use them both in 2018 :D, but if I have to admit that I do not see a 1 foil limitation in the SI of moth events hurting the class. I'd be really curious though to see where the class wants to go on that. 

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Well, don't know why you picked on me, but you try sticking a T foil on the bottom of your A mainfoil and see how long it stays there after a few good launches. There's a shitload of high grade carbon in them, and it's there for a reason.

 

6 hours ago, samc99us said:

Phil S,

 Frankly I am quite surprised at the costs in the Moth class, for example a Rocket Main foil and rudder foil package cost ~50% more than a pair of daggerboards and pair of rudders in the A-Cat from one of the builders. On par with the other class builder I believe, but we are talking two sets of foils! 

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Like Mika says the moth foils are much more complex than ACat foils, but its hard to see where all the extra money goes. Rudders are comparable but moth main centreboards/foils are a complex item.

Most of the cost of foils is in the mold and labour, and the hardware. Carbon laminate only costs about $300 per kg for material. A set of moth foils weigh maybe 4kg, but cost over $10,000. Moth sailors also are much more particular about foil finish than the ACat people. I see lots of sand scratches on ACat foils just from inserting them in the cases, and no moth sailor would tollerate marks like that. Almost no moths use foils straight from the mold. Everyone paints them. But a lot of people have tried making foils and few manage to get into production and make it profitable. Winning races is still vital for sales, not cost.

But I am also interested in radio control gliders and these are also complex in construction with many components and even smaller mechanical parts. But several manufacturers in Europe can produce and sell gliders up to 4m wing span, weighing well under 2kg, all for less than $3000. Similar CNC molds, but bigger and more complex in design, similar detail fit between components, and similar internal linkages, many more stages in  construction and customers with similar performance demands as moth sailors. Compared to moth foils these seem incredible value. 

I have made both moth foils and gliders and know I find the moth foils much easier.

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First of all, thank you for your help offline, Phil S.  You're a great ambassador for the Moth class.  Wish we had more ambassadors like you here in the US.

Wouldn't a single foil rule change nothing?  What I mean is that just because you have to choose which foil you take to a regatta, it doesn't change that you spend the money for two sets in the first place, just like Mika pointed out above. The competitive sailors are going to buy multiple sets anyways, the money has been spent, taking one or two sets to a regatta doesn't change the price.

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What a one foil rule would do is promote foils which work over a wider range of conditions. Designers would be encouraged to make more universal designs and not speciallist high wind or light wind foils. After a while the exteme designs would disappear altogether and everyone would only have one set. It would take time but the end result would be less foils and less expense. ACats and I14s have had one equipment rules for years.

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I am 100% with phil on that. People and builders would adapt pretty quickly to the rule.

Only thing I would not like of a 1 foil rule, though, is that we would probably loose the chance we have now to start foiling regattas in 7 knots with the big foils on.  And I know very few life activities which are more painful than lowriding a moth :D

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It's not just about the top guys though. There are a lot of weekend warriors who would prefer high–lift foils so they can go out in lighter breeze and have more of a chance of foil tacks. They really don't care about losing a knot or two off their maximum speed once the breeze is over 15kn or so, where it's much more about skill through waves.

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1 hour ago, RobG said:

It's not just about the top guys though. There are a lot of weekend warriors who would prefer high–lift foils so they can go out in lighter breeze and have more of a chance of foil tacks. They really don't care about losing a knot or two off their maximum speed once the breeze is over 15kn or so, where it's much more about skill through waves.

+1

and this goes for the sport of sailing too!

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6 hours ago, aardvark_issues said:

Well, don't know why you picked on me, but you try sticking a T foil on the bottom of your A mainfoil and see how long it stays there after a few good launches. There's a shitload of high grade carbon in them, and it's there for a reason.

 

Aardvark,

  That was not my intention and I apologize upfront. Your prices were public so I referenced them; I was trying to find the Mach 2 foil prices but they weren't readily available in a quick google search, so again my apologies. Your boats are also works of art and I'm not saying that level of detail could be justifiably sold for less.

I am also by no means discounting the t foil junction. I do composites engineering professionally to pay for my sailing addiction so I am pretty familiar with these sorts of issues; a straight T is among the worst load case for carbon (a thin L junction is worse) and I know at least one person locally who broke a lot of main foils at that junction.

All that being said, the tooling costs are lower, by roughly 50% for a set of Moth foils than for a set of A foils. A cat main boards and rudder winglets are different from port to starboard, so that is 4 complete sets of tools required for a re-spin, plus the rudder tool, and the main board molds are larger rather complex shapes that practically require 5 axis milling. I think what we have going for us right now is a lower priced, reasonable quality Eastern European builder that has outlayed a lot of their own time and money developing new foils. They also have in-house machining or very reasonably priced local machining services (think 1/2 or more less than what you would pay for comparable services in the U.S or Western Europe). A complete set of foils from the main Western European A builder is probably closer to Moth foil prices, $8k or so last I heard.

Phil S, once upon a time I built 1.5m carbon composite gliders in a low rate production environment. Getting the finish quality up is important and you are right, there are a lot more excellent products in that space now at phenomenal prices. When I started, models simply weren't available as they were mostly built by smaller shops (much like many of the Moth foils), prices haven't changed much since higher volume production came on line (primarily out of Asia) but quality has kept going up.

BTW I will be painting my A foils and babying them as I do understand the importance of scratch free foils to performance. Unfortunately the realities of inserting from the top limit damage control measures as sand and dirt are naturally attracted to daggerboard trunks.

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During the 2017 AGM at Garda Worlds I brought up the idea of 1 equipment rule (with the aim of reducing cost), however I had very little support in the room. Maybe 3-4 people expressed their support, however majority felt that it was not necessary and that the "unwritten rule" of 2 pieces of equipment is adequate. The argument back was "you cant stop people spending money if they want to". I agree, however you certainly can reduce the price of a competitive moth. I have to admit that I had similar response years ago when I first suggested this. Bruce McLeod and I discussed it on Mothcast too. Majority of the members (present at these AGM meetings) do not want to see a change.

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So I actually put together an electronic control system for a moth, but decided that with current technology its benefits were limited so never installed it. My reasoning is

  • Although sensors can pick up the level in 100ms or less, the speed of response of the actuator was limited. A 6V actuator was responding at about 3s full range which is substantially less than the speed of response when using a wand. Faster actuators were possible but with a substantial power demand impact
  • The actuators required significant power demand, and when you consider the time required for a 4 race day plus some maneuvering time, resulted in a very hefty battery pack, the size of which was impacted by the speed response of the actuator - so either a large amount of weight(several kg), or a battery pack that may mean you do not finish a race or 2.
  • As Rob said, the maximum benefit of electronic control would require complete knowledge of the boats situation, and to do that would require a large number of sensors, and failure of any $1.50 sensor could put paid to a whole race and then cause hours of faultfinding work.

So in anything other than butter smooth conditions where response time dynamic impacts are minimised, the wand still offers the best overall response.

Strictly speaking, electronic control has two potential benefits.

  • Offset compensation from your target ride height, which is done by the standard ride height adjuster on every modern moth, and
  • The ability to move away from the standard sine/cosine control dynamic function that all the existing linkages are dependent on, however with the advert of cam control this has also been resolved without the use of electronics. The use of cam control now means that the dynamic response can be  changed for at most the cost of $1 worth of plastic and a phone conversation, rather than a process control degree, and plastic does not have an issue if it gets wet. 

Personally I would love to play with electronic control, but I don't see it offering any real benefit for the moth class in terms of competitive development as yet. For the record, I have now bolted on a cam system and wouldn't go back. For those questioning the cost of the electronic system, in terms of components, it was comparable in cost to a full standard wand installation. But probably alot less reliable.

But to go on with your idea of development, I think the Furuya-San Foil design shown at Japan to be a potential significant step forward. No exposed push rod, interference drag of the main foil minimised even further. I would love to see this concept explored further. As always with he moth class, the step forward will come from an angle you do not expect. I can't wait to see what good idea someone comes up with next.

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Hi punchy,

I have seen the picture of the Furuya-San foil in the 2016 worlds thread. Is there any information on how it works or is that a trade secret? Some sort of bent leaver that moves the attachment point of the push rod to the inside of the vertical?

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Let’s look at a comparison of two theoretical sailors with some fictional assumptions for comparison. 

Sailor A - 65KG - 6 knot take off

Sailor B - 90kg - 9 knot take off

Let’s assume three foil designs. 

Foil A - General foil with a top speed of 25 knots.

Foil B - A high lift. Lowers the take off to 5 knots for Sailor A and 6 knots for sailor B top speed 20 knots.

Foil C - Small foil. Raises take off to 9 knots for sailor A and 11 knots for sailor B. Top speed of 28 knots.

Based on sailing bits prices, the foil sets are about $5000 each, so to have all three choices you need to spend $15K (the price of a waszp)

Those who can only afford one set (they do exist) will choose the least worst foil option trading take off speed vs top speed.

With the current 2 sets foil rules, the small sailor with multiple foils has a distinct advantage, they can use a high lift in light winds for a 6 knot takeoff and then swap to a small foil when the wind kicks in for a high top speed.

Compare that with a larger sailor who can only afford one foil. 

The larger sailor, can try and minimise his take off disadvantage with a high lift, but he risks significantly impacting his top speed if the breeze kicks in.

If the larger sailor chooses the small foil, he risks destroying his light air take off if the breeze drops.

The larger sailor will probably choose the mid range foil and try and live with a lower top speed, and higher takeoff,  loosing at both ends but trying to be ok in average conditions.

A one foil rule, basically will force the  whole fleet into a midrange foil optimised for a wide effective range, with a slightly higher takeoff and lower peak top speed. 

People are against the one equipment rule mainly because it reduces their personal options. The problem is that as the cost increases, less people can afford those options anyway.

The most important voice in this debate is not the people at the AGM, it is the ones that love sailing Moths but can’t afford to be at the worlds to discuss the issue .

 

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2 hours ago, m_kiel said:

Hi punchy,

I have seen the picture of the Furuya-San foil in the 2016 worlds thread. Is there any information on how it works or is that a trade secret? Some sort of bent leaver that moves the attachment point of the push rod to the inside of the vertical?

It would be nice to see what is inside that but I suspect you are on the right track. My bet is it is some form of internal drive system, RDS is one, IDS is another very popular one these days on the RC side: http://servorahmen.de/index.php?id=112

Very stiff linkage setup that keeps everything internal.

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Its just internal linkages, nothing complicated but pretty fiddly. Furuya-San had made the whole foil as one piece and then put an opening at the bottom to allow you to connect it all up.

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If we all need to make our T foils in one piece to gain a few % performance, attendance at distant Championships will become more expensive and fleet numbers will suffer further.

Already the iminent Bermuda WC attendance numbers have crumbled compared to last year in Malcesine, mostly due to the costs involved. The class is becoming much more cost sensitive.

Total sales of new boats has shrunk considerably. But the up side is that used boats have never been better value.

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Thanks for the info. Already checking on one that was listed for sale.

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On 1/26/2018 at 6:31 PM, Phil S said:

If we all need to make our T foils in one piece to gain a few % performance, attendance at distant Championships will become more expensive and fleet numbers will suffer further.

Oh boy, you'd hate the design I did.

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Hi Moth Sailors,

If somebody could provide me with a simple figure I would be very happy.

I have no Mach2 near home at the moment, and I would like to know the vertical distance between the horizontal "wing" of the main foil and the sail foot or boom gooseneck, in sailing conditions or maximum cunningham tension.

Thanks in advance

Erwan

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7 hours ago, Erwankerauzen said:

Hi Moth Sailors,

If somebody could provide me with a simple figure I would be very happy.

I have no Mach2 near home at the moment, and I would like to know the vertical distance between the horizontal "wing" of the main foil and the sail foot or boom gooseneck, in sailing conditions or maximum cunningham tension.

Thanks in advance

Erwan

The gooseneck position remains the same no matter what the downhaul tension or sailing conditions are, what exactly are you looking for?  What design sail are you using. Bent boom or straight boom?

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I am looking for average dimensions in order to compute the righting moment when the boat is foiling.

As the boat heels to windward, I need the the distance between the foil and the gooseneck or the sail foot; Does nt matter that much. Good proxies would be perfect,; it is not about 1 or 2 cm.

I will be travelling for the next days and be back saturday.

Best regards

Erwan

 

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I meaure my boat as around 1.75m. So between 1.7 to 1.8m depending on boom heoght and which model CB is used.  Mine is 1.35m for the CB and 0.45 for the boom above deck.

 

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Similar in my case. 135cm centerboard. 25 stump, 5 cm from stump to boom attachment. So 165 to boom attachment and probably 170 to 175 to sail tack, depending on downhaul tension

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Thank You very much Mika,

At first glance, you don't need much twist in your sails 

ie: with 5 m/s TWS or 10 knts you have barely more than 2.5°  apparent wind twist Windward  and 6.5° downwind, (between 6 and 23 feet above the water)

You probably need very stiff leech .

And according to the low AR, you probably need deep camber and powerful sail section downwind in this kind of wind speed (10 knts True Wind Speed)

Best Regards

Erwan

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