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Strange lee/weather helm effect

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    Posted: 29 Jun 06 at 10:24pm
Just to clarify, you should always carry some weather helm upwind.  This is quicker as you make ground to windward better (with the rudder acting as a foil stopping you slipping off sideways better).

Obviously not too much though or the rudder drags too much. 
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Post Options Post Options   Quote redback Quote  Post ReplyReply Direct Link To This Post Posted: 01 Jul 06 at 7:44pm
An easy way to check if the mast is upright is to cleat the main haliard so that it just touches the side deck on one side of the boat and then see if its the same on the other side of the boat.
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Post Options Post Options   Quote Rupert Quote  Post ReplyReply Direct Link To This Post Posted: 02 Jul 06 at 7:17pm

Originally posted by Calum_Reid

Shrouds are rarely the same length. It is sensible to measure them. You will be very lucky to have a set of exactly identicle shrouds!

OH and btw this talk of boats not being able to take rig tensions etc and using low ones to prtect the boat seems odd because when your sailing alon up the beat your leward shoud often goes slack meaning that there must be more tension in the windward shroud that the ammount of tension you have pulled on. Now you can stop the leward shroud going slack but it takes ALOT of tension. For example in the 400 (admitidly in a big breeze) we would sail with over 500lbs and still have a slack leward shroud.

It may seem odd, but it works. The classic boat for low rig tension is the Firefly, and the sails are cut to make low rig tension work. Our Firefly is nearly 50, and is still competitive in the fleet. I have my doubts that and Vagos will be racing in 50 years, but the premis is still the same - low rig tension means folding your boat up less, even though windward shrouds go tight.

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Post Options Post Options   Quote redback Quote  Post ReplyReply Direct Link To This Post Posted: 13 Jul 06 at 12:07am
This is how I see it.  The rig tension is the main factor in prebend of the mast.  When the pressure on the rig starts to slacken the shrouds then the prebend is no longer under control.  Its best if this transistion occurs at a wind speed which corresponds with the change from being underpowered to overpowered.  The right rig tension is the one that creates this relationship.  If the boat is not stiff enough the rig will slacken before you get maximum power and this may mean you lose power.  I can certainly depower my 4000 rig by easing the rig tension (although there are other complicating factors like rake).  A flexible boat will mean a rig which is unpredictable.  This is only one of the reasons why a stiff hull just feels better than a floppy one.
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Post Options Post Options   Quote JimC Quote  Post ReplyReply Direct Link To This Post Posted: 13 Jul 06 at 4:49am
Rig tension is a lot less critical in non trapeze boats.

Back in the early 70s before big rig tension (and boats that could take it) there used to be a moderate wind situation where the gust would come, crew would hit the trapeze, all the tension would come off the windward shroud and onto the leeward one, the spreaders instead of pushing the mid mast to leeward by the tension in the windward shroud would be pushing the mid mast to windward, the top of the rig would flop off, the whole thing depower, and back off the trapeze again...

So if the crew is on the wire and you reduce the rig tension on your 4T the spreaders are doing less and the rig depowers. On an RS400, by contrast, this doesn't happen nearly so much. So on a trapeze boat monumental rig tension keeps the windward spreader working...
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