Australian Moth Class Association

Hi all,
I am starting a new thread because as we are introducing the class in Italy we have to face a new problem.
Our new website and the European Championships on Lake Garda generated lots of interest.
We obviously don’t have a second hand Moth market and very few are willing to spend big bucks for a new Moth just to try and see.
Now my question is: is it possible to build a Moth foiler for beginners?
I am thinking to a more “user friendly” boat, if I may say so.
Not an all out racer but a boat that trades in top performance for economy and ease of handling but a foiler nevertheless.
May be a strange question for those of you that are totally devoted to racing but I think it may be worth investigating.
All input will be enormously appreciated.
Thanks,
Marco.

Marco,

One option may be a slightly wider (say 350-380mm BWL), plywood box hull with all the foiler gear? Something a bit like a fat version of Phil Stevo's chainsaw mk 2, but with Illet or fullforce foils (considering it's closer to the UK from ITA than to AUS) would be a fairly cheap option? A cheaper method of ride height control may be good too... doug culnane's diamond foils seem to be a fairly good compromise of controlability vs. cost, so that could be an option too.

The boat may be a little heavier and take longer to get up on the foils, but would be a little cheaper (or more breakable compared to the carbon boats) and suitable for those wanting to sail moths.

Also, something like Ian Ward's scow foiler arrangement might be good, as it is on a old (wingless...) boat, which is more stable and yet on foils it is a still a quick boat. When it's not flying, it is a bit like a big windsurfer, so would be good for beginners.

Ultimately, the downside is that these boats would almost certainly be home-built as mose builders these days are more interested in building something that will be fast, delicate and expensive, not cheap and easy. But, as Moths are getting very close to their structural limits nowadays (I am doubtful that bare hulls will get much below 7kgs, or much below 25kgs rigged), a well designed and well sailed fatter foiler should be able to race on the same playing field. In reality, foils are a great equalising device... they allow anyone who wants to jump their boat's performance (and have the money to buy them) to do fairly well, regardless of their hull's age. A downside of this is old boats aren't built to take the stresses of foiling, and may require reinforcement of the centreboard case and transom (to take the moment applied by the rudder gantry).

Jon
AUS 9157 (may see some foils shortly)

there isnt really any obvious place to save money in a moth without compromising durability and toughness, both of whihc are essential for beginers.

you could make ply hulls pretty easily, and make alloy wings, but i wouldnt go changing the moth design fundamentally. just change for cheaper materials where possible.

I wouldnt go trying to save too much on the foils and control systems as what we have now works and everythign else people have tried to date has been inconsistent

if a pro built hull cost 5000$ aus out of carbon, then a glass one might be 4000, a ply one might be 1000 if you diy or3000 if you get them made.
ther isnt a huge amount to be saved by going cheap.

Thanks Jon and AS
I was in fact thinking of a simple three carbon-foam panels hull ,vacuum bagged on a flat table and then joined with carbon tape at the chines. This configuration will result in much sharper chines than it’s now common especially in the forward part of the hull. How much will it lose for this in terms of perfomance I don’t know. But the main problems come from the foils. We have now in Italy two Fastacraft and one Full Force and we can use them as a platform to test cheaper foils.
Sort of backward step I reckon, but cost is a great issue for young sailors here and I think this have to be our target.
Since foils are very thin and almost solid carbon already why not using a T shaped flat carbon laminate as a core and then fair it with lighter material?
Remember, we are not trying to match Ilett foils but just set a decent compromise.
Several years ago I built a carbon Snipe centreplate.
Using conventional wet lay-up and squeezing it in a press I was able to achieve a good fiber to resin ratio, obviously not to compare with pre-pregs but good enough.
Cost for a simple flat T mould would be negligible .
All this could be easily done and will probably be strong enough.
Marco

I think we have the present performance of moths because of carbon fibre and high quality manufacturing. This has resulted in very light and very strongboats. If we compromise either we will not go anywhere near as well.

If the boat ends up heavier it will not fly in as light winds. If it is too heavy it will never fly. If it is not strong enough it will brake. If it is both heavy and not strong enough it will brake more often. This is much more significant with foiling / flying than with archimedian boats.

I know because I spent last season in this position with little flying, lots of crashing and lots of breakages. I have spent 6 years trying to build cheaper boats buit have ended up this season with a Thorpey hull and full carbon accessories.

The class has come along way, give credit to the present and past builders of these excellent boats, Ilett, Linton, Thorpey, and also Patterson and Colleridge.

There are a lot of very good boats out there, but if you want to fly you need the best.

I think if designed well, a flat pack carbon foam boat could be made reasonably quickly and easily. The foils are the harder part, but possibly if you went for a bigger thicker section you could make them out of glass which would reduce the cost a bit.

However, after now having built two glass/foam boats in the last couple of years, It just isn't worth it. Much better off spending the money on good materials than having to worry about it later. Unfortunately there is no cheap solution if you are wanting to be really competitive.

Any cost reductions that are made for foils will need to come from the processing. There's a finite amount of carbon required for the application. What we need to do is speed up construction and reduce the labour component so that they can be more widely available.

ive got a simplified rudder system now, ive eliminated the flap pushrods bellcranks etc, my foil, is straight out of the mould just filled and sanded/polished, not painted. it required a rudderbox but that is easy and quick to make(3hrs tops) and a 3 custom plastic thingys. one of which is a rectangular block with a 5/16th endmill runn though the middle, one of which is a cylinder with an off centre 1/4 threaded hole, and the last of which is a piece of breadboard with 2 holes, one of which is filed square. add a piece of threaded rod and a rudder pin and you got a tilting rudderbox.

total time in laminating and fairing the rudderfoil was about 6hours to get a wet blank in the mouldand cleaned up. one hour to sand off the flashing, and about 2 hours of snading and filling. this dosent allow any curing time obviously, but making a foil in a single process has got to be easier and cheaper than multi step prepreg stuff

A good compromise might be wing mounted foils that are now illegal. You could get all the speed on a much more stable platform.

Im in the latter process of designing my new hull, I have dedicated a small amount of cash to the project and as few hours as I can spend. The top sides will be flat panels and the bottom will be male moulded. A few glue joins later and I should have a pretty good hull, good enough to float as thats all it has to do. Test panels indicate hull weight 9 kg or so. There is going to be no or little carbon in the hull to keep the price down. Im going for a wood/glass/foam composite. cant say too much as things may change but I may post some images either CAD renderings or build photos later on.
I hold out hope for a more cost effective form of foil mothing. and I think Brett is thinking along the same lines.

Backing out of the statement I made yesterday in the interest of encouraging more people, I have assessed the various low cost designs Andrew and I have churned out over the past 6 years:

I think the best of our home made ply hulls for foiling purposes would probably be Bent and Twisted, which is the original Youth version of the stressed ply hull designs.

I say this because it was an exceptionally good boat in light winds, so it might be able to slightly compensate for the extra foil drag when a foil moth is unable to fly.

It was not a great fast reaching boat, it seemed to bog down with maybe too much keel spring, but this should not matter once airbourne.

Also the slight V shape forward might soften the impact of crashing off the foils, and save damage to the light low tech hull. It has a very fine stern so would not drag much on take off.

If anyone is keen go back to my original web article and build it straight, not bent and twisted like we did.

I think the original is in Adelaide, but Steve has the clone ...Anyone can be Imature in Melbourne.

Hi
has anyone tried to stress the foam instead of plywood? I use this technique for side tanks on dinghys. One layer of glass (or carbon or 1 mm plywood) on the exterior side of the curve. When cured can be flexed and stabilized with an inner layer.
Never used for compounded curves thou.
Phil Stevenson's panels shape for Bent & Twisted could possibly lend themselves to this technique.
Marco.

They are only made from 2 mm ply, which is very flexible until stressed. It also bends very tight just off the keel. I doubt anything thicker or anything with carbon would be flexible enough.

We used the flat foam panel system on Andrews black boat. The sides were cut out and the inner skins applied and cured before the sides went on the mold. We did the bottom similarly after heat bending it to shape. In our case the inner skins were kevlar. The joins were simple overlaps of the kevlar inner skin.

The foam was then faired and the outer carbon skin applied in one go.

In Aust it costs about $500 for the ply, timber, epoxy, foam and finish for a ply boat. And it costs about $1800 for the foam, carbon, Vynelester and finish for a foam boat. The difference is not that huge as a % of the whole boat.

As for foils there is about $300 worth of carbon and epoxy in a fin/foil (CB or Rudder) But the real difficult bit is all the mechanism, pushrods, ends, bellcranks, etc. If you can not make all this yourself it is a real fiddle to get it sourced anywhere else other than John Ilett.

Hi.
I decided to go for the lowest cost solution. Nothing can beat stressed plywood in this respect so I will build Phil Stevenson’s “Youth” version and we will put on the Italian website photographs of every phase of construction, hoping to encourage others to do the same. As a boatbuilder in wood, I must admit that I am really intrigued by compounded plywood construction. The hull will be on display at the Genova boat show in the Boero Yacht Paints booth, Italian dealers for West System epoxy resins.
2 mm. Hoop pine being unavailable here, I have to use Occume (Gaboon) 2 mm. instead.
I made two samples 10 cm x 50 cm, number 1 with grain along main dimension, number 2 with grain crosswise main dimension.
Number 1 with a 500 grams weight in the middle deflected 30 mm.
Number 2 with a 200 grams weight in the middle deflected 47 mm.
Specific gravity is 0,45.
If anyone have 2mm. Hoop pine scrap pieces lying around, I would be interested to compare these figures.
Thank you.
Marco.

The Gaboon is about 45% lighter per sheet than Hoop Pine, so its a good option...

Jon

Hi.
I received today the 2 mm gaboon plywood.
Good stuff, very flexible indeed. Hope compounding will stabilize it nicely.
Construction will begin next week.
About mast position: wouldn’t it be worthwhile moving the mast a bit forward to increase foilbase?
I seem to understand that on Rohan’s boat this made foiling easier though possibly not as fast as the previous location.
That could be good for a beginner’s boat.
Can somebody confirm this?
Thanks,
Marco.