[drewdotcom]

Are home built moths as competitive as those built by boat builders like Mach 2. I'd imagine the major problem would be weight? home builds being heavier on average

[aardvark_issues]

I dont think it is the fact that it is built at home that makes it heavy - what counts is experience and in this case persistence. I think unless you have good direction/instruction in how to do it expect your first one to be slightly below par and a learning experience. It also depends a lot on how much you are aiming to do - if you are just making the hull and buying in foils/spars and tubes (make up 80% of a Moth build anyway) then there is not too much to go wrong.

Having said that, boatspeed around the course is more dependent on whether you can keep it upright, not whether it is fast...

Either way, much fun to be had in building and tinkering with Moths and would recommend it heartily!

[Dave Lister]

drewdotcom, on Jan 22 2010, 08:57 AM, said:

Are home built moths as competitive as those built by boat builders like Mach 2.

YES

[J Buoy]

I think it depends upon whose home they were built in...and foils too....anyway I know squat about this subject as I sail ancient slow boats.

[TeamFugu]

Building your own boat has rewards way beyond just saving money. A Moth hull should be fairly easy to build. It is the internal structure that holds everything together that is important. They hull is just a minimalist float to get you started.

I would highly recommend giving it a go but your first boat should not be from your own plans unless you are an architect by trade. I'd recommend finding plans that someone has well sorted out and then follow them closely. Your next boats after that may be modifications you make based on what you think will improve the first.

I'll add a +1 to the comments about quickest around the course has more to do with ability to keep the boat upright all the time and in the case of a Moth, also airborne. We spend so much time stressing over the hardware we use when it is the software that makes the biggest difference.

I'd say if you have the time, space, and desire, go for it. One of the biggest problems is to keep going through the 1/2 way point. Early on, you have a lot of energy. About half way through you'll say, "This looks like shit and will never work." If you can get passed that point, suddenly you'll walk into the "shop" and say, "Wow that looks f'ing cool and I did it!"

[The Black Pearl]

There are 2 guys down at ABYC in Long Beach who have built their own and are both lightening fast esp up wind. Hard to hang on to hem up wind in teh X8 but they have yet to sort out thier down wind speed. Nat has a blog spot. Google Chinzilla!

[Phil S]

Home built moth is achievable but no one has homebuilt a competitive set of foils. Not even Dave despite his reply above.

Unless you have some aero/hydrodymanic skills on the computer, access to a very good CNC cutter, high level of laminating skills plus vacuum and baking equipment plus good source of high quality carbon and appropriate resins, add the patience to start all over again when you get it wrong several times, then just buy them from the very few people who do have all this already (less of course the few of these who will not even sell you foils alone like McConachys)

[WCB]

The Black Pearl, on Jan 22 2010, 08:08 PM, said:

There are 2 guys down at ABYC in Long Beach who have built their own and are both lightening fast esp up wind. Hard to hang on to hem up wind in teh X8 but they have yet to sort out thier down wind speed. Nat has a blog spot. Google Chinzilla!

BP Here's the link http://chinchillazil...p;max-results=6

[Dave Lister]

your such a wet blanket phil

[TeamFugu]

Dave Lister, on Jan 22 2010, 02:19 PM, said:

your such a wet blanket phil

But he does have a point. I think I'd probably take on all but the foils. Well, I might try foils later but I'd start with someone else's and only make my own if I thought I could improve but then that would be unlikely.

[WCB]

I'm going the route that Phil talked about. Mast, boom and rack tubes are all C-Tech. Rudder gantry and rudder stock/tiller, spreaders will be Bladerider, foils will be either Bladerider or Assassin likely, sail is a KA MSL13, hull is homebuilt. I didn't want to get involved with building my own blades. I want to take a few of the variables out of the build, not to mention the time and possible failure rate.

[madmothist]

drewdotcom, on Jan 22 2010, 02:57 AM, said:

Are home built moths as competitive as those built by boat builders like Mach 2. I'd imagine the major problem would be weight? home builds being heavier on average

The problem is all materials and technique. My home built hungry beaver hull came out at about 18 pounds (carbon/kevlar vacuumed over a nomex honeycomb core.) The success was directly dependent upon knowledgeable friends helping with the build, the right equipment (vacuum/mold) and a suitable workspace. As others have said the hull is the least of your worries. Suitable racks (my tubes were made by vandussen) can be cut and joined, and will probably be a little heavier than production molded racks. The rig and sail should be bought from one of the known manufacturers. Decide if you want to spend the big bucks for carbon rigging or are satisfied with 3/32" wire. The big question is foils. My first set of homemade foils worked but when I bought a production mainfoil I noticed a big difference. The best thing about a M2 is how every piece is assembled with little or no play. Slop is still my biggest problem. At 20 knots, little movements between hull/rack/foils can cause a big headache.

Bottom line: if you can join up with some other folks that speak composite construction and are interested in building a moth too, then go ahead and build. Try the foils if you're up for a challenge; otherwise buy 'em from John Illett. Whichever route, the boat is only half of the story in going fast. Expect a steep learning curve (where I'm still sitting...) Good luck.

[teknologika]

Historically home built foils were done more from a perceived cost-saving, or wanting to tinker point of view. That is changing now and more people are considering home building because it is a way to potentially go faster than off the shelf "production" foils.

Re the tech needed ... my brother home built a CNC router using a hobby cnc controller, for less than the cost of a set of foils. I had never 3D modelled anything 18 months ago, an before I started building foils I had never female moulded anything we can now go from starting the design to having a completed MDF mould in 3 days. If I can do it ... anyone can.

The main difference that the commercial builders have is easy access to good pre-pregs and HM carbons.

My main foil is about 200g heavier, and the same approximate performance as an Ilett main foil. I would be no quicker if I was using one of John's foils. I am now at the point where my next foil horizontal will be different foil sections than the rest of the fleet, whilst also having some production foils as a baseline to compare to.

Phil is right that it is a false economy that homebuilt is cheaper ... they aren't ... and they are a LOT of work, however I strongly it can be done, it just hasn't been done YET.

[gui]

Humm ... I'd say my first foils were a "success". They were fat and slow, the flap was poor, but I only broke the first strut. Never broke the T, they were demountable. Second iteration was a mix between my strut and Bill's horizontal which was a big improvement. Never broke it. 3rd iteration was shit, mainly my fault, 4th will hit the water sometime in spring or summer, depending on my motivation. Skinny strut/main foil. Could be a short season for G again!
I don't know what to tell you. If you're not lazy, do it. If you build a boat, you'll have the tools to build all that stuff.
In my experience, away from a major fleet, building is cheaper than buying.

[atg]

gui, on Jan 25 2010, 03:10 AM, said:

Humm ... I'd say my first foils were a "success". They were fat and slow, the flap was poor, but I only broke the first strut. Never broke the T, they were demountable. Second iteration was a mix between my strut and Bill's horizontal which was a big improvement. Never broke it. 3rd iteration was shit, mainly my fault, 4th will hit the water sometime in spring or summer, depending on my motivation. Skinny strut/main foil. Could be a short season for G again!
I don't know what to tell you. If you're not lazy, do it. If you build a boat, you'll have the tools to build all that stuff.
In my experience, away from a major fleet, building is cheaper than buying.

The foils are not that hard. And like Gui says, if you break one, it's no big deal, because you can always make another. Having said that, I have never broken the mainfoil that I built, despite some very hard (ab)use. I had made other foils, but never anything like that. I thought hard about it and made it to last; if it broke tomorrow I'd be surprised but it doesn't owe me anything at this point. The rudder I built may yet fall apart, but it hasn't yet, and it seems pretty solid. So just like everything else: ask a bunch of people for advice, copy what works slavishly and you will find you can put something credible together on the first go. Who knows - you may have a knack for it and invent some cool new way to do it.

It is definitely cheaper than buying; but that assumes you are into this sort of thing and already have a lot of the stuff around.

[now_what]

when one considers that the entire world market for moth foils is probably less than 500 boats, ( split over 3-4 pro builders) one has to recognize that mass production effects are very unlikely to be having much price lowering effect over building ones own.

Therefore when "buying" rather than building one is paying for total input costs, some profit, and perhaps (one hopes at least ) reliability and engineering expertise within the design and implementation.

It would be useful to know how long it takes the "self-built" foil makers to make their own from scratch. (i.e. some effort numbers that ignore duration issues like swmbo wants the lawn cut and kids taken to soccer before you can wax the mold or whatever).

With that information one can cost their own time against what the sellers of foils offer ( assuming they will sell to you).

Anyone want to offer up their experience/knowledge of effort/hours from first hand foil making?

Perhaps take the whole rhino/cad part out of it and assume that someone has made a "good" design in g-code available for the class. ( sort of "open sourced" in orientation ). This is a big exclusion, I know, but to my mind that is "design" not "build".

...nw

[Phil S]

now_what, on Jan 28 2010, 03:44 AM, said:

when one considers that the entire world market for moth foils is probably less than 500 boats, ( split over 3-4 pro builders) one has to recognize that mass production effects are very unlikely to be having much price lowering effect over building ones own.

Therefore when "buying" rather than building one is paying for total input costs, some profit, and perhaps (one hopes at least ) reliability and engineering expertise within the design and implementation.

It would be useful to know how long it takes the "self-built" foil makers to make their own from scratch. (i.e. some effort numbers that ignore duration issues like swmbo wants the lawn cut and kids taken to soccer before you can wax the mold or whatever).

With that information one can cost their own time against what the sellers of foils offer ( assuming they will sell to you).

Anyone want to offer up their experience/knowledge of effort/hours from first hand foil making?

Perhaps take the whole rhino/cad part out of it and assume that someone has made a "good" design in g-code available for the class. ( sort of "open sourced" in orientation ). This is a big exclusion, I know, but to my mind that is "design" not "build".

...nw

I know from discusssions with AMAC that the Bladrider and Mach 2 foils were designed as coputer 3d models and then the molds were machined by CNC from solid metal molds. He said that the foil molds took almost a week to machine because the finish required multiple passes. I also understand that the Fastacraft molds were made by similar technology from composite materials. At least these manufacturers are well ahed of what most amateours can dream of.

Bruce McLeod and maybe Bill Beaver are the only amateurs I know who has made a CNC machines and designed and built some foils. They is not yet "competitive" (as asked in post 1)

This degree of manufacturing acuracy is barely justified unless you have the design skills, experience and knowledge to create a good foil design. This was ilustrated well when John Ilett recently bought a new design from someone who he respected, made molds and produced a foil which no one could get to go fast.

Then we get to the structural issues. Most people can buld foils straight and stiff enough. Its actually possible to carve a good piece of timber and cover it with enough carbon to do a good job. Getting it to an accurate cross section which will not ventilate at 20+ knots is another issue but there are a few well built hand shaped foils and verticals out there, not winning races though.."not competitive?"

The big trick is the T joint, whether a solid built-in T or a socket and plug. These are the big challenge. The trouble is that in a chord of less than 120mm and max thickness of 16mm, less flap and the stagger needed to align pushrod with flap, there is only a 35mm left of the vertical and horizontal to make the joint. Many have tried many different methods and still they fail. Even the professional ones break sometimes, but less often than they used to. A break on the water often results in a loss of a foil, its also common for the pushrod to tear open the trailing edge of the vertical. A big loss if you get it wrong. The Mach 2 foils are even thinner and narrower so the joint they have succeeded in making is something special.

Mach2 are the first to use high mod carbon. All the pros use prepreg uni carbon vacuumed in and baked to cure. Result is high density lamiate with minimal resin and very high strenth and stiffness. All ending up lighter than anything built by other methods aproaching equivalent strenth and stiffness.

I made my initial molds by screeding bog along a trough. (method John Ilett used in his first molds 7 years ago.) It took me several days and about $200 of materials. Those molds has made nearly 20 verticals and 12 horizontals. Less horizontals because the section and plan form were not nearly good enough. I have tried maybe 10 different ways of making the T joint, many as repairs to cracked or broken joints. I think I have finally got a system which works. I have thrown away maybe a couple of thousand $ worth of carbon.

The material to make a set of foils cost me about $A600 or maybe 50% of the cost of a set of unfinished commponents from Fastacaft, It takes a good full days work to prepare a mold, prepare core and fibre, and then laminate and vacuum the halves. Another day to dress the halves, install Tees and join the halves. Considering that mine never turn out as light or as easy to finish as Johns, I think his are good value and have been buying bits from him for my recent efforts.

I hope I have filed in a few blanks and made the ambitious more aware of the effort, equipment and material needed. I agree with Bruce and Karl (ATG) that its all possible, because I have done it too, but the post 1 question was about being competitive with the Mach 2 and its becoming pretty obvious on the race track that there is very little at present which is competitive with the Mach 2, particulary anything with home made foils. (Dave, don't pipe in until you have made your own foils too)

[Dave Lister]

So if u dont make the sail ,mast and wing tubes its not a home build Wow this is a tough crowd. I think if u make the hull its a home build. Speed isnt all about the foils......ILL DO AS I PLEASE PHIL :)

[rtrs]

Dave Lister, on Jan 27 2010, 05:00 PM, said:

So if u dont make the sail ,mast and wing tubes its not a home build Wow this is a tough crowd. I think if u make the hull its a home build. Speed isnt all about the foils......ILL DO AS I PLEASE PHIL :)

just out of curiosity, who's foils do you use?

[Dave Lister]

johns c board and rudder vert

[Phil S]

I repeat my first sentence from my first post here:
Home built moth is achievable but no one has homebuilt a competitive set of foils. Not even Dave despite his reply above.
No one has made a reasonable argument against that statement.

Go build your moth, but you will save a lot of time and money if you buy your foils just like Dave. You'll be more competitive too.

[teknologika]

My old square foils were an 8 hour build from start to finish 4 hours of prep and 4 hours of layup with tooling in place, not counting final filling and painting time.

I have changed my method and make the foils as follows:

1. Computer design 10-30 hours, but realistically probably 100+ hours if analysis is thrown in.
2. CAD to CAM prep - 10 hours ( producing tool paths and converting to g-code).
4. CNC cutting time 20-40 hours on the machine.
5. Mould finishing prior to first use 8-10 hours.
6. Lamination of skins 2 hours each (I do one at a time across 4 days and there are 4) so lets say 10 hours.
7. Lamination of T join - 2 hours
8. Gluing in control tube and pulltrusion - 2 hours
9. Bonding together 3 hours
10. Cut in and bond flap 5 hours.
11. Finishing and painting 10 hours+

So from start to finish is about 100-150 hours from scratch, with tooling in place, an extra pair of hands, and working in parallel not counting cure time it is about 3 full days work for a foil approximately.

I prefer the longer drawn out method as you can do it after work spread out across a couple of weeks, and not spend a whole day in the workshop non-stop without a break.

For me buying off the shelf bits from John Ilett simply saves time, especially if you are buying in a semi-finished state.

[gui]

Phil S, on Jan 27 2010, 05:58 PM, said:

I repeat my first sentence from my first post here:
Home built moth is achievable but no one has homebuilt a competitive set of foils. Not even Dave despite his reply above.
No one has made a reasonable argument against that statement.

Go build your moth, but you will save a lot of time and money if you buy your foils just like Dave. You'll be more competitive too.

Somehow I think this is going to change. Isn't Bora building his own rudder? Main foils are a little trickier but it would seem to be the next logical step ... Dunno.

[atg]

Phil S, on Jan 27 2010, 09:28 PM, said:

I hope I have filed in a few blanks and made the ambitious more aware of the effort, equipment and material needed. I agree with Bruce and Karl (ATG) that its all possible, because I have done it too, but the post 1 question was about being competitive with the Mach 2 and its becoming pretty obvious on the race track that there is very little at present which is competitive with the Mach 2, particulary anything with home made foils. (Dave, don't pipe in until you have made your own foils too)

Major advances nearly always come from the home builders. Look at Dave's rudder - everybody wants one.

A quote comes to mind from a very accomplished comic book writer I met the other day. There are only a couple of hundred people in his field. He clearly enjoys his work; Hugh Jackman pretty much owes his film career to this guy. I asked him, "Would you advise young people today to enter your field of work, or has it changed so much that it wouldn't be a good idea?" He said "I tell everyone the same thing: If you can be talked out of it, you should be, because it's hard, the competition is fierce, there is no guarantee of success, and no one knows what the future is. But I loved it so much no one could ever have stopped me."

So in terms of building Moths, if you can be talked out of it, you should be. Phil has done a pretty good job of laying out the relevant arguments, i.e. you won't beat a Mach 2 any time soon, or perhaps ever, you won't get rich, and you will have failures. But those arguments haven't stopped some of us from having a lot of fun trying. There is a lot about that process that is fun and rewarding, not least the people you meet who share an interest in these sorts of things. The technology is accessible to anyone with a dedicated interest in such things. Yes it costs money, but so does a Mach 2 last I checked. And there are plenty of people who you might readily compete with if you can tack just a bit faster than they can - no matter what kind of boat they sail. Around the world Mothies consistently report that they end up duking it out with people of their sailing ability race after race, even in a big regatta, regardless of boat type. So don't be afraid to fail - there is a lot of encouragement, knowledge and free advice available from the fleet. All you have to do is ask, and the technical aspect of being able to design, modify or construct your boat is one of the things that keeps the Moth class going strong decade after decade.

Obviously designing and building something like a Mach 2 foil isn't easy, or everyone would do it. But that hardly means it isn't worth trying, or that it is impossible, notwithstanding the fact that the world is full of people who will try to to tell you otherwise.

[aardvark_issues]

Phil S, on Jan 27 2010, 09:28 PM, said:

All the pros use prepreg uni carbon vacuumed in and baked to cure. Result is high density lamiate with minimal resin and very high strenth and stiffness. All ending up lighter than anything built by other methods aproaching equivalent strenth and stiffness.

I'm only chiming in because it is probably relevant to the home build crowd. The UK National championship winning foils (Beating several fast M2's...) are not pre preg and could be made by methods within reach of a dedicated amateur.

I agree that noone with homemade foils is competitive, but it is not because they can't do it - its because they haven't yet.