Main sheet posts are common on several classes - IOM's for example. I have one on my Santa Barbara and like it - seems to improve close hauled control and helps to prevent sail shape distortion. However, I rarely see one on 12 meters.
I don't care for the appearance, but is it legal?
Rob Hill
Main Sheet Post
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Main Sheet Post
by rob1416 » Fri Sep 29, 2006 6:18 pm
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by kahle67 » Fri Sep 29, 2006 8:58 pm
Yes, it's legal and some have it.
Many in the EC-12 class prefer to have the ability to sheet vang which cannot be done with a post unless the boom is on centerline. With a good eye and a bad ass sail winch such as the RMG with the latest spiral drum, it's amazing how much control you actually have on the leach of the main and twist. Very important in such a lead heavy boat especially sailing at one of your typical inland venues with puffy and shifty winds, at least to me. I do agree that in some classes, the post may be desirable.
Reichard Kahle
Charleston, SC
Many in the EC-12 class prefer to have the ability to sheet vang which cannot be done with a post unless the boom is on centerline. With a good eye and a bad ass sail winch such as the RMG with the latest spiral drum, it's amazing how much control you actually have on the leach of the main and twist. Very important in such a lead heavy boat especially sailing at one of your typical inland venues with puffy and shifty winds, at least to me. I do agree that in some classes, the post may be desirable.
Reichard Kahle
Charleston, SC
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by Rick West » Fri Dec 29, 2006 9:40 pm
They all had it, Rob. The reason it is slanted is that mounts in the rudder area. The piece is slim and apparently strong. There is only about 1 inch clearance with the boom.
I have asked for information. Rod Liddy is currently on holiday outside Motueka and will likely send something soon. He indicated that it is all off the shelf stuff.
...94![[8D]](./images/smilies/icon_cool.gif "Cool")
I have asked for information. Rod Liddy is currently on holiday outside Motueka and will likely send something soon. He indicated that it is all off the shelf stuff.
...94
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by s vernon » Sat Dec 30, 2006 1:36 am
Judging from the pictures of the international regatta, they probably optimize the boat for very very heavy wind where we sail in light to medium to heavy wind and optimize it for light to medium. We want to harden up the leech with the main sheet. Would they want to harden up the leech using the main sheet in very very heavy wind? I doubt it. They want to let the main twist off to lessen the power. So they would want to use a post and we would not.
I know you did not ask for my thoughts, Rob, but you got em. I figure you might be asking why they use a main post in NZ.
Scott
I know you did not ask for my thoughts, Rob, but you got em. I figure you might be asking why they use a main post in NZ.
Scott
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by Rick West » Sat Dec 30, 2006 2:44 am
They want to sheet close to the centerline of the boat. In recent years here that is the trend also among top sailors. Yes, there is sheet vanging at the times thought needed but the trend has been to power the top of the rig with a tighter leech to offset the pressure to twist off.
With a B Rig I footed off while holding the shape down the leech to no more than five degrees off under pressure. At the higher velocities there is little variance in wind direction to six feet above the water. The boat pointed more that thought, held the bow to the sea with drive and hardly any leeway till we hit 20 knots. Then there was water over the bow and leeway began as the clew of the main was held out of the water purposely.
While it is very true, in looking at their rigs and rigging, that one thinks of the wind source at their venues; more than one approached me as to why I tuned flatter that all others. My position has been the same as here, I can control the boat better closer to the wind if I can keep the sails still; the leech is tight, the top third is not twisted and the foot of the main has more depth for drive. Danny told me this at White Rose some years ago and he was right. The thing is to increase the pressure on the rig as the wind pressure increases and Newport proved it could be done. Now, I feel there is control beyond the design and beyond what RD's in this country will allow us to sail.
The post will allow us to follow this regime more than current sheeting that allows the boom to lift as it draws toward the centerline from wind pressure. That lifting change all endeavors visioned on shore.
A post does not hinder the needed tuning for our lighter air sailing. However, it will demand better pretuning of the sails and rig on shore to meet the challenge on the water. Those of us that have sailed the Shamrock J Class with a limp mast know the drill. It is not a guru thing but one in vision of the sail plan in the water under pressure.
The hull in the shop now that will take shape into a boat later this year and will have this long post; the challenge will be to tune it for Elon.
BTW, Jack Wubbe's 1864 has a small post and my guess is it will grow.
...94
With a B Rig I footed off while holding the shape down the leech to no more than five degrees off under pressure. At the higher velocities there is little variance in wind direction to six feet above the water. The boat pointed more that thought, held the bow to the sea with drive and hardly any leeway till we hit 20 knots. Then there was water over the bow and leeway began as the clew of the main was held out of the water purposely.
While it is very true, in looking at their rigs and rigging, that one thinks of the wind source at their venues; more than one approached me as to why I tuned flatter that all others. My position has been the same as here, I can control the boat better closer to the wind if I can keep the sails still; the leech is tight, the top third is not twisted and the foot of the main has more depth for drive. Danny told me this at White Rose some years ago and he was right. The thing is to increase the pressure on the rig as the wind pressure increases and Newport proved it could be done. Now, I feel there is control beyond the design and beyond what RD's in this country will allow us to sail.
The post will allow us to follow this regime more than current sheeting that allows the boom to lift as it draws toward the centerline from wind pressure. That lifting change all endeavors visioned on shore.
A post does not hinder the needed tuning for our lighter air sailing. However, it will demand better pretuning of the sails and rig on shore to meet the challenge on the water. Those of us that have sailed the Shamrock J Class with a limp mast know the drill. It is not a guru thing but one in vision of the sail plan in the water under pressure.
The hull in the shop now that will take shape into a boat later this year and will have this long post; the challenge will be to tune it for Elon.
BTW, Jack Wubbe's 1864 has a small post and my guess is it will grow.
...94
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by jack wubbe » Sat Dec 30, 2006 9:12 pm
I have sailed all year ( 2006 ) with a main sheet post at about 2 1/2" above deck. My boat that I took to New Zealand #1864 had to have the post cut off to fit in the crate. Thats not what I wanted it just was what had to be. My new boat #2123 ( in the shop now) will have a post at about the same height.
I'm not a fan of sheet vanging, but 90% of USA EC-12 skippers out there use it. The main gets so flat that there is no drive and we all know boat speed is what it's all about.
After all is said and done it boils down to different strokes for different folks. [:D]
I'm not a fan of sheet vanging, but 90% of USA EC-12 skippers out there use it. The main gets so flat that there is no drive and we all know boat speed is what it's all about.
After all is said and done it boils down to different strokes for different folks. [:D]
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by IanHB » Sun Dec 31, 2006 2:30 am
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"> My new boat #2123 ( in the shop now) will have a post at about the same height.<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">
The same as ? ...........2 1/2 inches or the cut down version. And a storm rig. YES.
Cheers mate.
DO IT NOW, Before it`s to late
The same as ? ...........2 1/2 inches or the cut down version. And a storm rig. YES.
Cheers mate.
DO IT NOW, Before it`s to late
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by jack wubbe » Sun Dec 31, 2006 3:45 pm
Hi Ian;
Here in Naples Fl. we dont need a storm C rig when its 95 deg. and 98% humidity and a strong breeze is 5 knots. But my next trip to Kiwi country I will have one in my sail locker.
Happy New Year to you and all our New Zealand friends.
Cheers, [:o)]
Jack and Mary Ellen
Here in Naples Fl. we dont need a storm C rig when its 95 deg. and 98% humidity and a strong breeze is 5 knots. But my next trip to Kiwi country I will have one in my sail locker.
Happy New Year to you and all our New Zealand friends.
Cheers, [:o)]
Jack and Mary Ellen
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by IanHB » Sun Dec 31, 2006 9:48 pm
Jack, my storm rig crack was just a cheap shot at getting a laugh,[:D]
Your sailing conditions sound ideal. How much to buy a small apartment there?[8D][:o)]
(The weather here is rubbish at the moment)
And the answer to my question on the height of the post is.....
Best wishes to Mary Ellen and yourself.
DO IT NOW, Before it`s to late
Your sailing conditions sound ideal. How much to buy a small apartment there?[8D][:o)]
(The weather here is rubbish at the moment)
And the answer to my question on the height of the post is.....
Best wishes to Mary Ellen and yourself.
DO IT NOW, Before it`s to late
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by jack wubbe » Mon Jan 01, 2007 9:05 am
The new rig has not been built yet, but the post will be 1/2 inch below the boom. Also here in the USA we cannot use curved booms so that might change your dim. somewhat.
Jack [:o)]
Jack [:o)]
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by rob1416 » Mon Jan 01, 2007 9:48 pm
Thanks for the comments, Rick. My new boat will have one as well. Now I have some theory to apply in non Chicago, light air conditions.
The posts work well on our Santa Barbara's here where conditions often mimic what I suspect you saw in NZ.
Rob Hill
The posts work well on our Santa Barbara's here where conditions often mimic what I suspect you saw in NZ.
Rob Hill
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by s vernon » Fri Feb 08, 2008 7:55 am
I re-read this thread and I have to ask.
How can it be that sheeting the main boom to a raised post would hold the boom down more than sheeting to a fairlead on the deck as the boom gets sheeted close to the centerline.
My thinking is that the only time that you really get ANY downward pull on the boom from the sheet on a post is when the boom is right on the centerline as opposed to sheeting to the fairlead on the deck where you start getting downward pull much earlier. By the time you are sheeted to 5 degrees, you have quite a bit of downward pull on the boom, while at that point you would pretty much still only be pulling in using a high post. And even with a half-height post you would be getting less downward pull than a deck failead at that 5 degree sheeting angle.
Maybe the post is beneficial for a different reason than providing more mainsail leech tension. Maybe the fact that it does not pull down on the main boom is the benefit. (?)
Scott
How can it be that sheeting the main boom to a raised post would hold the boom down more than sheeting to a fairlead on the deck as the boom gets sheeted close to the centerline.
My thinking is that the only time that you really get ANY downward pull on the boom from the sheet on a post is when the boom is right on the centerline as opposed to sheeting to the fairlead on the deck where you start getting downward pull much earlier. By the time you are sheeted to 5 degrees, you have quite a bit of downward pull on the boom, while at that point you would pretty much still only be pulling in using a high post. And even with a half-height post you would be getting less downward pull than a deck failead at that 5 degree sheeting angle.
Maybe the post is beneficial for a different reason than providing more mainsail leech tension. Maybe the fact that it does not pull down on the main boom is the benefit. (?)
Scott
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by MichaelJ2K » Fri Feb 08, 2008 9:15 am
This is an excellent thread, will there be a page on the build site covering this subject? I'd love to know more.
Mike Denest
EC12 #899
Mike Denest
EC12 #899
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