Moth Tuning

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Nessa
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Re: Moth Tuning

Post by Nessa » Tue Aug 06, 2013 9:21 pm

here she is! I can't get any depth in the sail at all. Should I fiddle with the battens?
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bornagainmothie
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Re: Moth Tuning

Post by bornagainmothie » Wed Aug 07, 2013 1:36 pm

Mystery moth looks smart, is that a new paint job?

Yes, i think the battens are too stiff, particularly the top ones.
Outhall is too tight, or maybe the boom is hanging low because sail is not up to top of mast?




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Nessa
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Re: Moth Tuning

Post by Nessa » Wed Aug 07, 2013 7:11 pm

the sail is as high as the black band, which is about 8 inches from the top of the mast. It's difficult to pull it a lot higher. It is a new paint job - mint turquoise, plus the boat is a lot lighter for having plenty of old paint and epoxy (over the paint) removed and being thoroughly dried out.
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Rupert
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Re: Moth Tuning

Post by Rupert » Thu Aug 08, 2013 10:22 am

Personally, I'd check the black band (or ignore it) - the sail really looks like it should be higher up the mast.
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Nessa
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Re: Moth Tuning

Post by Nessa » Thu Aug 08, 2013 10:53 am

I agree, I'm going to ignore it, plus I'm going to buy some new halyard from Jonti today while I'm at Grafham.
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bornagainmothie
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Re: Moth Tuning

Post by bornagainmothie » Thu Aug 08, 2013 1:46 pm

Black bands could be legitimately moved up as they are related to the luff length rather than a maximum height.

Halyard???? Considered uncool in Moth circles! The boat falls over anyway so feed the sail in while its lying down. only a short loop of thin line up and over the top and back to a hook near the top of the mast. No stretch, no cleats to slip

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Nessa
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Re: Moth Tuning

Post by Nessa » Thu Aug 08, 2013 6:28 pm

my boat doesn't fall over! Or at least not on its trolley, it waits until it has me alone on the water..... So a halyard is perfectly acceptable, cool or otherwise, plus it saves me having to trun the boat over, then pick it up again.
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Re: Moth Tuning

Post by scorpion_1925 » Sun Aug 11, 2013 9:04 pm

Boat looks good, I would advise against too much mast rake, it tends to lead to weather helmin stronger winds.

I like the idea of a lowrider meet and training session I'm based in York with my magnum 8

Got to say I fitted mine with a halyard its so much easier than lying the boat down every time
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jpa_wfsc
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Re: Moth Tuning

Post by jpa_wfsc » Mon Aug 12, 2013 9:28 pm

Depth - and full length battens...

You should have strings at the ends, do them tighter causes more pre-load in the battens, causes more fullness.

But don't overdoo it, as most of the time you will probably be fighting for less power!

Luff tension is very imnportant - it looks like the same needlespar as on The Hopple (Skol Moth) and aq very simmilar sail. It is designed to bend a lot to flatten the sail. Realy, one should have a powerfull and adjustable cunningham on a sail like that - it would be the most effective power management tool. On the Hopple we just have a tie it off and cope system which is on a list of improvements to make - but other bits keep breaking and falling of so its never got done!

Kicker - fit leech tell tales and only use the kicker to manage sail twist. I.E. have all leech tell tales streaming away from the sail in the same manner.

Outhaul - on our mast / sail has almost no effect on sail power at all.

Halyard - we have a pre stretched kevlar halyard which still, stretches while sailing, and the sail comes down the mast maybe 2 inches during the first few minutes of sailing. I would very much agree that a mast head halyard lock is the right solution. These can still be used with a halyard to lower and raise the sail if you want to. And get rif of the black band.. you need the head of that sail to be right up, and then you have a chance to get the battens bent using their tensioners, and the sail falt when needed useing cunningham.

Mast rake - lots of rake if its windy, and sail with the board up a little to compensate. Mast virtical if there is not enough wind to plane.
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Re: Moth Tuning

Post by Spiderman » Mon Aug 12, 2013 11:30 pm

Hi Nessa,
The boat looks great and I very much look forward to seeing it at the National Rally.
I agree with Lyndon's suggestion that the battens are probably too stiff for the sail. Your sail is very similar to the Anderson Aerosail that I have been using on the Shelley and appears to have almost the same rather unusual panel layout.
I am using mine on a fairly stiff Needlespar with quite flexible narrow ash battens which allows it to set with a decent amount of draft unless I start pulling quite hard on the controls. I also use a halyard for convenience although when I was sailing Moths more seriously I used to rig the boat on its side and secure the head of the sail with a small clamcleat at the top of the mast. If you use 4mm dyneema or Vectran (more expensive) then the halyard wont stretch much and your sail will stay at the top of the mast. You then have the obvious benefit of being able to hoist and lower the sail without having to find space to tip the boat over. Also at some clubs you would end up tipping the boat over on tarmac, gravel or concrete none of which will do the boat or the sail much good.
If it isn't the battens we can compare rigs more closely at the Nats if I bring the Shelley which may help identify the problem.
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Re: Moth Tuning

Post by fleabertoo » Thu Aug 15, 2013 1:56 pm

Rupert wrote:Lee told me he had passed the boat on to you, Alex - I suspect the learning curve was a bit steep for him?

I have one of its centreboards here - Lee gave me a snapped one to try and fix. I'll get it to you one day, somehow, but no promises it won't just snap again - there wasn't much to work with!

Haha Rupert! :D yes, certainly a steep learning curve but I needed a new sail for the Lightning so sold the accidental Moth to Alex....who is doing a very fine job of getting around our water I can tell you!
Don't let all the questions disarm you all into thinking he's constantly swimming :mrgreen:
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Re: Moth Tuning

Post by JimC » Sat Aug 17, 2013 10:04 am

Suggest that if you are going to have a halyard and don't mind an external one the best option is to have a clam cleat at the top of the mast in order to gain the halyard lock effect - like an RS300... This is what I have on my Moth. As a masthead sheave I cut down the case of a Laser mainsheet block so that it sockets in the end of the alloy mast. Its large enough diameter for the external halyard to work.

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Nessa
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Re: Moth Tuning

Post by Nessa » Sat Aug 17, 2013 10:07 am

I have thought about that too - I'm going to have another look at it today. I watched one of the lads sail it on Tuesday and the battens ar definitely wrong.
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Re: Moth Tuning

Post by alexshaw48 » Sat Aug 17, 2013 9:59 pm

Hi all,

Had another sail in the moth today, very breezy and nothing broke! :D

Tried a lot more downhall, and got a fair bit of mast bend, was very gust so couldn't really tell if it helped but i'll assume it did :)

I did put the onboard camera on so here is some of the footage from today, enjoy!

http://www.youtube.com/watch?v=mtUJQfyw ... e=youtu.be

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Nessa
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Re: Moth Tuning

Post by Nessa » Tue Aug 20, 2013 8:32 pm

Guven that there will be a fair few moths at the National Rally does nayone have nay ideas on 'old money' two or three figure pys for them? I have looked at the suggested figures for Roadford, but it would be really useful to be able to convert them somehow. Also, what about the mystery moth from the mid seventies?
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