Strange lee/weather helm effect

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...

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.

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. 

Check the spreaders.