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 Post subject: My inverting mainsail.
PostPosted: Wed Jun 24, 2015 10:25 pm 
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Joined: Sat Jul 11, 2009 4:28 pm
Posts: 70
I would like to open this thread in the hope of getting some input from as many experienced IC sailors as possible.
In my early days of Nethercott sailing I had a big problem with the inevitable capsize after a big gust when the wind got behind the sail and popped the battens,inverting the camber. Now,when sailing a Nethercott, I can see this beginning to happen when the wind is up, because the luff starts to lift and I will flatten the main with a yank on the Cunningham,plus pull on more kicker. And with the sail properly tensioned I am often surprised at how full the sail can be and for everything to be in control.
Now that I am sailing the much more difficult lightweight new rules IC,there is a lot less time to react to events, and in stronger winds 14kt+
the same thing is happening. And these problems are compounded by now rigging a flatter sail which inverts even more readily.
My gut feeling is that I am just not adequately practiced at sailing the light boat and that I am not throwing it around as I should,but it would be great to have some discussion.
Perhaps I just need a flatter cut of sail which will flatten completely, and will flop from side to side easily when a gust gets behind it.
What do you think? Maybe I need more time in the boat. Maybe I need to concentrate on sailing to the flat jib, hiking as hard as possible, and dumping the flat and bladeing main to stay level. Probably need some therapy. It is quite probable that I am not sailing aggressively enough, but any constructive comments would be greatly appreciated.


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 Post subject: Re: My inverting mainsail.
PostPosted: Fri Jun 26, 2015 12:19 pm 
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Joined: Mon Sep 22, 2003 7:28 pm
Posts: 225
Location: United Kingdom
Hi Rob
I remember in previous boats some thing similar happening quite a lot. A big gust comes through, you release the main and it flogs, the boat gets pushed sideways eaxch time it flogs stalling the boat and then you get knocked over. I still get this but its only in very windy and gusty conditions, ie the day it was blown off in Loch Lomond the last time we were there. I don't think its about being agressive, trying to remember how I get through it, I think I dump the main and bear away for the duration of the gust so as not to stall letting the main flog and try and keep the boat flat, you end up going very fast but not high, ease up after the gust. It very important to pull on the cunningham in these conditions as it flatterns the top of the sail and lets it flog "softly", experiment with kicker, with the cunningham on hard you might want plenty of this as well as it will help keep the sail flat, but too much kicker hooks the main and makes tacking diffcult.
Is this in chris's boat or the morrison? I think Chris used lots and lots of cunningham.....

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Alistair


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 Post subject: Re: My inverting mainsail.
PostPosted: Fri Jun 26, 2015 3:15 pm 
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Joined: Sat Sep 06, 2003 8:13 pm
Posts: 93
Location: United Kingdom
I agree with everything Alistair said in his reply. I was out on West Kirby lake a couple of the days ago to give another bloke a go on the IC but the wind got up preventing this activity but enabling me to have a blast up and down the lake.... wind blowing across the lake - dead flat water. I could watch the effect of the gusts on the rig. The mast being used is the same bendy 50mm variety that Colin Brown used in San Francisco last year and we both recognise that it's just too soft. It's a Goacher main and cut pretty full. However, it was possible with enough downhaul to get the mainsail quite flat in the top third. I was hiking off the end of the seat, the gusts were such that they caused the main to invert in the top half and I was having to ease sheet as well. With the jib sheeted about an inch out the IC was comfortable and hammering along. (you wouldn't want to be sailing anything else in these condition but it would be useful if the Council or the EU would extend the length of the lake as the adrenaline rush doesn't last long enough). The Main didn't flog, which might have happened if the wind speed notched up again and because the water was so flat there's less resistance to the hull going quickly. Maybe waves would have slowed me down and increased the likelihood of mainsail flogging. Whatever,I am convinced that its essential to have flatter cut sails for the windy stuff with a stiff enough mast to suit. Its also a bit of an obvious statement but its simply important to get out in windy conditions to experience and progress how you can cope with the canoe. She's a challenge!

I strongly recommend the therapy though but you need to find your own therapist - mine's fully booked!

Tony M
GBR307 (on this occasion )


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 Post subject: Re: My inverting mainsail.
PostPosted: Sat Jun 27, 2015 5:10 pm 
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Joined: Sat Jul 11, 2009 4:28 pm
Posts: 70
This is all so very interesting.Thankyou.
There are a number of things that strike me. I believe it to be correct that you may be able to get a flat sail with a bendy mast, but this set up will not be efficient or fast.With Haydens incredibly bendy mast on Aus 17, I was able to completely flatten an otherwise adequately full sail (Gaz AC294 Rowsell Kevlar main). I once went out in loads of wind with this rig up and was amazed at how easy the boat was to handle. But it was so flexible and this floppy leach lacked driving power. But it would at least have survived a huge backing gust. I get the impression also that to torture the luff of a full sail to get it more or less flat, is not a good practice, because the sail becomes as solid as a wing, and when a gust gets behind it...WHAP...and it is solidly inverted. End of story! I notice in Alistairs video at Aldburgh that his main shakes back and forth at times. I wonder, if he had been able to pull down more Cunningham, (and a bit more kicker), whether it would still shake like that, or want to stay inverted.
Perhaps it is true that tensions on the sail edges must suit the strength of wind,otherwise the leach is hooked or too loose,etc.
It is interesting to see photos of the Nethercotts at SF mostly with full mains in strong wind, esp the Medway boys,but also Colin Brown,in a 50 kg boat.
It seems that a flatter sail would be worth trying. And also the technique of bearing off,mid gust,before the sail inverts,should provide some pleasure for anyone watching.Thankyou, it is something to try to get to grips with!
Alistair, yes that was with Chris USA boat,but I have been using my flatter Goucher main in over 10 kts of wind,as it has been easier to manage. But I do not know if I have ever been watching the top of the sail,apart from an initial glance to see that it is flat and bladeing. It makes sense that this part of the sail should be backing first in these strong conditions,if that is what happens. I have never looked!
And bearing off after dumping the main sounds so logical as something to work on. Thankyou.


Last edited by robert stebbing on Sat Jun 27, 2015 9:14 pm, edited 1 time in total.

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 Post subject: Re: My inverting mainsail.
PostPosted: Sat Jun 27, 2015 6:33 pm 
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Joined: Sun Dec 28, 2008 10:07 pm
Posts: 252
Just to confirm what Al said re Cunningham.......was out today is strong wind when my Cunningham broke. Was interesting to see the main backing, which it hadn't been doing before!......and also some nasty creases!
Gaz


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 Post subject: Re: My inverting mainsail.
PostPosted: Wed Nov 04, 2015 10:01 pm 
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Joined: Sat Jul 11, 2009 4:28 pm
Posts: 70
4 months down the line and I am racing in Plymouth in less than design wind,faffing around before the start in a Nethercott, with a not very full Goacher main. So the less than properly sheeted main, inverts from a puff. well its just not anything to be alarmed at! The Nethercott is heavy and therefore stable. there is not lots of cunningham down, and hardly any kicker, so you just grab the bundle of mainsheet above the block, and yank the sail back to deal with it....Dunno what all the fuss was about.
Well that was in easy conditions, in a heavy boat.
Once,when I was trying to get some inside knowledge from UK Steve Clarke,he said "Everything (ie all settings) has to be right, all the time,Rob" I am definitely becoming more and more aware of this fact.
There is no universal answer.
As soon as the wind increases by, say 4kts, then everything is suddenly different. You have too much power available and this demands a different procedure to deal with the boat, especially if you are on one of the light weight jobbies.
I AM getting to grips with it.More especially, the healthy use of Cunningham, to flatten the top of the sail.And the importance of having a kicker control that is available to use at any time. And through having the sense to look at the mainsail a bit more often.
Recently I was blown over, just heading up to a beam reach from a fast run in c15kts wind. That was because I got the rate of turn wrong and I had not eased the kicker enough. Perhaps I would pull up a bit of plate next time.
NEXT TIME I will get all the variables right!


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 Post subject: Re: My inverting mainsail.
PostPosted: Wed Nov 04, 2015 10:33 pm 
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Joined: Fri May 30, 2008 9:46 am
Posts: 217
Rob, respectfully, I think you are being too analytical about your sailing . As with all things in life a little bit of what you fancy won't do too much harm! I think set up your boat that way and sail it but be mobile and proactive with your head out of the boat and sail on feel and then and only then start tweaking bits. The boat is sailable even if poorly set up...particularly in the lightish conditions you mention. I think allow the errors to develop and physically identify the corrections progressively. Getting pulled over in a puff suggest more about attentiveness to light pressure increases,observations and your position in boat than your battens/Cunningham etc. I know, all easier said than done but it's a good way forward.
SteveAC310


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 Post subject: Re: My inverting mainsail.
PostPosted: Wed Aug 03, 2016 9:44 pm 
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OK. 9 months further down the line; I have this recurring image of a few American sailors who were really in control of their boats. One of them was David Clarke exiting Richmond Marina. When the wind was already up outside, you went from the completely calm marina into the windy channel inside the main breakwater, sometimes to be immediately dealing with a wind that was too strong (for me). I watched in amazement at the way David remained in control, sailing slowly with flat mainsail and loose leach, until he had the room to get up to speed and go flying.
One of the things that time-in-the-boat gives you is the ability to sail slowly when the wind is up. And this gives you more time and more control.
Something else that happens eventually is that you can and must be able to see the strength and direction of the gust. It seems to me that everything becomes much more difficult as wind strength increases. And this is compounded having a lightweight boat. To be able to see what is coming, before it arrives is great news!
Having exhausted my supply of Feathervanes, I decided to try sailing with no burgee, and after a few months have been amazed that I am now beginning to feel changes in pressure on the back of my neck, so that dumping of the sail, in a big beam reach gust just happens, almost automatically, before it hits the sail.
Now, when a big gust is arriving from ahead, or I am sailing into one on a fast run, I usually know about it before it hits the sail and am then able to adopt Alistairs technique. If the wind looks like getting behind the sail, I am already bearing away. Luffing at big gust is a no-no.
At Cargreen Yacht Club, we have been spending time recently concentrating on 3 areas in order to stay with that elusive Groove.
1.Boat trim in both planes; Without this being correct and constant, my experience is that the bow is reluctant to lift and go. Also you are already half way to a stagger at gust if the boat is partly rolling.

2.Mainsail shape; As conditions change, it has been noticeably beneficial to control the power in the upper main. In more than design wind strength, it has felt so good to greatly reduce the bend in those top battens, and having a flat sail for the gybe is just vital for control, in my experience. I have found that if the main is too full it will try to invert, especially if the kicker is not down enough.

3.Leech tension;At those times when the leech has been able to open at gust, the boat has felt much more stable and I have found, to get this right, it has needed constant referral, as the pressure changes. When there is loads of wind on the quarter, correct kicker and thus leech-give equals pleasure to be alive.

I do not know whether any of this stuff applies to the heavy Nethercotts, or whether I shall be barking up a different tree in a years time, as I have yet to be successful at sailing in extreme conditions.
What do you think?


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