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Mozzie Mainsail #64754
01/16/06 06:18 AM
01/16/06 06:18 AM
Joined: Jan 2006
Posts: 556
Somers, Westernport Bay, Victo...
Peter_Foulsum Offline OP
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Peter_Foulsum  Offline OP
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After too many years of perservering with the ancient piece of cloth I like to call a mainsail I've decided to buy a new one. I'm sick of being overtaken downwind and can't make the old thing any fuller. I take the downhaul tension off and it just gets flatter.

The question is which of the supplier to choose and what sail material is better. Do the newest generation sails allow for mast over rotation downwind ? If there is anybody who has used both Goodall and Irwin sails I'd like to hear from them.


Mosquito 1814
Macka Mozzie
-- Have You Seen This? --
Re: Mozzie Mainsail [Re: Peter_Foulsum] #64755
01/16/06 10:37 PM
01/16/06 10:37 PM
Joined: Mar 2003
Posts: 943
East Gippsland, Australia
Tim_Mozzie Offline
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Tim_Mozzie  Offline
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East Gippsland, Australia
Just to confuse the discussion, here is a list of the first 7 sails used in each fleet at the Nationals (one missing):

Place Sail No Boat Name Skipper From Sailmaker
1 1790 Bee Alert Gary Maskiell GLYC Irwin
2 1781 Voo Doo Bob Wilson PMYC Carl Blitz
3 1789 Immunity Neil Joiner GLYC Irwin
4 1775 Karma Cat Tim Shepperd GLYC Goodall radial
5 1786 Grey Area Rob Lott LMYC Goodall crosscut
6 1752 Nautical Nuts Stuart Ridge BeYC Clifton
7 1733 Touch'n'Go Garry Johnstone LBYC Goodall radial



Place Sail No Boat Name Skipper From
1 1745 Two Obsessed Mick Floyd BeYC Horizon
2 1788 Atreus Warwick Kemp ASC Goodall Crosscut
3 1787 Try Again Peter Cobden CCSC Ashby
4 185 The Ancient Mariner Simon Hallsworth ASC Ashby
5 1765 Aldebaran V Phil Pearce ASC ???
6 1746 Hexham II Andrew Copland LVYC Goodall
7 1794 Loose Screws Phil Warren-Smith RYC Ashby


I was using my old Goodall Radial, but that was actually made by Chris Boag and is not what you would get from Goodall's now. The luff round above the hounds was adjusted by Lindsay Irwin to make it a Cat sail rather than a sloop sail. I really like this sail, but like I said, I don't think it's possible to just buy one like it.

I own an Irwin sail almost identical to the one Gary Maskiell was using at the Nationals, which I use nearly all the time. These two were made with a heavier material than you usually find on Mosquitos. The Irwin sails are now made with the same lighter material that most others are made from. This is the sail that Neil Joiner was using at the Nationals. Like all current designs they have tried to maximise the area up high.

From what I've seen, that new Irwin sail of Neil joiner's is the fastest there is. If I was buying a new sail that's what I would go for.


Tim Shepperd
Mosquito 1775
Karma Cat
Re: Mozzie Mainsail [Re: Tim_Mozzie] #64756
01/19/06 03:59 AM
01/19/06 03:59 AM
Joined: Jan 2006
Posts: 556
Somers, Westernport Bay, Victo...
Peter_Foulsum Offline OP
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Tim,

Thanks for the info. It was much appreciated. Have since contaced Lindsay Irwin. For those interested cost for new sail is $1400 and F/glass battens $180 or foam sandwich battens $340.

Regards,

Peter


Mosquito 1814
Macka Mozzie
Re: Mozzie Mainsail [Re: Peter_Foulsum] #64757
02/27/06 03:45 AM
02/27/06 03:45 AM
Joined: Jan 2006
Posts: 556
Somers, Westernport Bay, Victo...
Peter_Foulsum Offline OP
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Peter_Foulsum  Offline OP
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Somers, Westernport Bay, Victo...
Got the new Irwin mainsail and foam sandwich battens on Friday and used it in 1st race Saturday afternoon 25/02; 0 to 8 knots. Upwind I seemed to be slower against my usual benchmark Mozzies but the downwind speed was incredibly greater. I used to get passed by the Hobie 16s on the reaches but now I'm equal or faster.

I need to work on my upwind settings . Used full downhaul and played with mainsheet tension from fully in to slighyly released. Does anyone have useful comments ?


Mosquito 1814
Macka Mozzie
Re: Mozzie Mainsail [Re: Peter_Foulsum] #64758
02/27/06 04:40 AM
02/27/06 04:40 AM
Joined: Mar 2003
Posts: 943
East Gippsland, Australia
Tim_Mozzie Offline
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Tim_Mozzie  Offline
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East Gippsland, Australia
Congrats Peter. Were you sailing sloop or cat?

One thing I would suggest (cat or sloop) is don't overdo the downhaul. Use more mainsheet to flatten the sail, but be ready to let the traveller way out (esp. if cat rigged), and don't let the foot out excessively.


Tim Shepperd
Mosquito 1775
Karma Cat
Re: Mozzie Mainsail [Re: Tim_Mozzie] #64759
03/01/06 07:16 AM
03/01/06 07:16 AM
Joined: Jan 2006
Posts: 556
Somers, Westernport Bay, Victo...
Peter_Foulsum Offline OP
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Peter_Foulsum  Offline OP
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Somers, Westernport Bay, Victo...
Tim,

I was sailing cat rigged; the crew ditched me nearly 2 seasons ago and have sailed cat rigged since the hull rebuild after Altona State titles.

If I use more mainsheet than downhaul won't I hook the leach ? Do I keep the outhaul pulled on heaps upwind ?


Mosquito 1814
Macka Mozzie
Re: Mozzie Mainsail [Re: Peter_Foulsum] #64760
03/01/06 08:02 PM
03/01/06 08:02 PM
Joined: Mar 2003
Posts: 943
East Gippsland, Australia
Tim_Mozzie Offline
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Tim_Mozzie  Offline
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Posts: 943
East Gippsland, Australia
Whether the leech hooks also depends on the wind strength. In trapezing wind it's pretty hard to hook the leech, but you just have to look at it and if you think it's hooked then sure put on a bit of downhaul.
I was just saying don't go overboard with the downhaul. Those sails just don't seem to need it.

I would never pull the outhaul on heaps upwind. Probably the tightest I would ever have it is so that the curved in foot is just touching the boom in the middle and that would be in very strong winds. Otherwise I would usually have a gap between the boom and the sail which gets bigger the choppier the waves get. I suppose in survival (panic ?) conditions I might pull it out tight but I'm not sure that's the right thing to do - it's probably better to have some drive at the bottom end of the sail even in wild conditions.

Sorry I can't give you very definite measurements but I tend to set these things by the feel of how the boat is going rather than by numbers.

And be prepared to drop that traveller!


Tim Shepperd
Mosquito 1775
Karma Cat
Re: Mozzie Mainsail [Re: Peter_Foulsum] #64761
03/02/06 04:42 AM
03/02/06 04:42 AM

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Hi Peter,

hope you don't mind me throwing in my two bobs worth, what weight are you? I could be wrong but the dropping traveller Tim refers to is something I at 90kg. rarely do, I know Tim Neil and Peter do it but they are in the 70 to 80kg weight range.

So it realy depends on a few factors, I would only drop traveller when I was unable to depower the mainsail any more with the downhaul, with the mast rotation at about 20 degrees and the foot as Tim described it, just touching the boom.

But the most important thing is what feels fast for you.

Oh and having the mast raked back as far as you can without causing to much weather helm. On a older boat with centreboards not at maximum distance back this will be more upright than newer boats.

Regards Gary.

Re: Mozzie Mainsail [Re: ] #64762
03/06/06 05:09 AM
03/06/06 05:09 AM
Joined: Jan 2006
Posts: 556
Somers, Westernport Bay, Victo...
Peter_Foulsum Offline OP
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Peter_Foulsum  Offline OP
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Somers, Westernport Bay, Victo...
Gary,

I weigh in at around 86 - 87kg at the moment but with the girls on weightwatchers it's heading downwards.

Boat still didn't feel fast upwind last weekend in 10 to 15 knots. Easily beaten off the start line. Very small amount of weather helm which is just right. Mast rotated to around 60 degrees. Isn't 20 degrees a bit small ?

Had a "little" problem with pulling on the mainsheet then pulling on a little more; the mast hound broke clean through at the top of the stays and I ended up with the rig on top of me. It reminded me a bit like sailboarding.
No damage to the sail and am in the process of fitting new hound, straightening mast base pivot fittings and buying a new tiller extension.

I suppose this is a lesson to others. New sails and improved sail technologies means more stress on the remaining fittings.

See you next weekend at the state titles. Did you get a Mozzie for the weekend ?


Mosquito 1814
Macka Mozzie
Re: Mozzie Mainsail [Re: Peter_Foulsum] #64763
03/06/06 06:54 AM
03/06/06 06:54 AM
Joined: Jun 2001
Posts: 9,582
North-West Europe
Wouter Offline
Carpal Tunnel
Wouter  Offline
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Joined: Jun 2001
Posts: 9,582
North-West Europe


Did you feel like the boat was bound up when going upwind ? The was propelled forward reasonably but felt slower than how it should be.

Wouter


Wouter Hijink
Formula 16 NED 243 (one-off; homebuild)
The Netherlands
Re: Mozzie Mainsail [Re: Wouter] #64764
03/06/06 07:10 AM
03/06/06 07:10 AM
Joined: Jan 2006
Posts: 556
Somers, Westernport Bay, Victo...
Peter_Foulsum Offline OP
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Peter_Foulsum  Offline OP
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Somers, Westernport Bay, Victo...
Wouter,

Yes it feels like it is bound up and would rather heel over than surge ahead. A couple of times I was having to feather into the wind gusts to avoid capcising.



Mosquito 1814
Macka Mozzie
Re: Mozzie Mainsail [Re: Peter_Foulsum] #64765
03/06/06 07:36 AM
03/06/06 07:36 AM
Joined: Jun 2001
Posts: 9,582
North-West Europe
Wouter Offline
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Wouter  Offline
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Joined: Jun 2001
Posts: 9,582
North-West Europe


Had that once, then Daniel van Kerckhof stepped on board and showed me how it is done.

You sail is too full, too much draft. Or you squaretop is not twisted off enough.

The bound up feel comes from having a draggy tip vorted; squartop is not twiste off enough

The excessive heeling comes from a mainsail that is too full.

Remedy, reduce mainsail draft and increase twist in the top. Square top leech should be about 200 mm of the centreline, sometimes even more (Glenn ashby advice).

Reducing draft : derotate the mast. 60 degrees sound like a whole lot to me even on a teardrop shaped mast. Pull on downhaul more while letting off some mainsheet tension. A beneficial side effect of these actions is that the leech will twist of more. Exactly what you are looking for. When lucky the top of the mast will bend off to lee and have the top twist more still. Best would be if this addition twist is so great that you can add some mainsheet tension again to bring it back in and thus flattening the mainsail even further. Now you have decreased draft a little more.

Boat should not be at all flighty anymore and it should quite suddenly pick up speed when nearing the optimal trim. It may even be the case that you'll need to come of the trapeze, not enough power to keep you out. However, you are going faster just the same. Trapezing is not a must, do it only when the optimal trim requires you to trapeze out. If you are not trapezing in optimal trim but everybody else is then take a hard look at your prebend settings, you may have too much of it, making the middle part of the leech fall away to much and basic losing power that way. DON'T try to keep yourself out by pulling the head in to far. The result is a flighty boat and slowing yourself down, either way you'll be less competitive.

I found that when trapezing is marginal on these boats (new mainsails) that then it is better to sit in, hike out and do alot of mainsail sheeting in the gusts. It is better to open up the sail and shed excessive power that way then the be on the trapeze and close up the sail to keep you out thus adding alot of aerodynamic drag, slowing you done.

Hopes this helps

Wouter







Wouter Hijink
Formula 16 NED 243 (one-off; homebuild)
The Netherlands
Re: Mozzie Mainsail [Re: Wouter] #64766
03/07/06 06:30 AM
03/07/06 06:30 AM
Joined: Jan 2006
Posts: 556
Somers, Westernport Bay, Victo...
Peter_Foulsum Offline OP
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Peter_Foulsum  Offline OP
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Somers, Westernport Bay, Victo...
Wouter,

Thanks for the info. New sail isn't square top but I suppose the principle is the same.

Will try playing with the settings this weekend at the Mozzie Victorian State Titles. Will be lots of other Mozzie gurus there too so I can look at their settings.

Regards,

Peter


Mosquito 1814
Macka Mozzie
Re: Mozzie Mainsail [Re: Peter_Foulsum] #64767
03/08/06 06:33 AM
03/08/06 06:33 AM

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Hi Peter,

yeah Wouter is on the right track bar square top, but principal is the same, if it feels bound up, open the exhaust, pull on downhaul. Also leech on new mains are generaly at tightest when new, so it is easy to close leech with too much sheet tension.

Won't be at Mossie states but good luck.

Regards Gary.

Re: Mozzie Mainsail [Re: ] #64768
03/13/06 07:28 AM
03/13/06 07:28 AM
Joined: Jan 2006
Posts: 556
Somers, Westernport Bay, Victo...
Peter_Foulsum Offline OP
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Peter_Foulsum  Offline OP
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Posts: 556
Somers, Westernport Bay, Victo...
Lots of gurus and lots of help from the Mozzie fraternity at the Victorian State titles. Found that use of downhaul, mainsheet, and outhaul is the key. It's just a matter of getting all elements right at the same time. A bit like learning to walk all over again. Yes, definitely found that the downhaul tension is the key to opening the leach at the top. At times I had all the telltales flowing Can't get any better than that. Also I have no more concerns about top battens being too flexible. It can all be fixed with the proper ammount of downhaul and mainsheet tension.

The ammount of downhaul tension is all relative to the pulley ratios. For instance if you use 10:1 then there is moderate force. If you use 6:1 then you pull on as hard as you can and then it's probably not enough and you just end up with sore hands.

Also found that my mast section is a "dinosaur" and was probably OK twenty five years ago when it matched the sail techology of the time ie. a heavy straight stick with a small amount of bend. It made me wonder how long the existing mast will hold up to the stresses. Will purchase a new mast section this week and start planning to transfer fittings.


Mosquito 1814
Macka Mozzie

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