Is it just me or does mast rake seem to get the most blame for weather helm? Everybody seems to think that too much rake moves the CE aft of the CLR and creates weather helm. The first suggested cure is...shorten the forestay. Did all these boats REALLY come from the factory with forestays that were just a tad too long? I don't think so. LOok at the geometry. Even with two feet of rake, the CE can't be more than a foot aft of its correct position. That's a very small offset. The whole discussion of the relative position of CE to CLR completely overlooks what I thgin are the two primary causes of weather helm: poor sail trim and excessive heel. With proper mainsail trim, the CE can be moved fore and aft much farther, more easily and much more quickly than adjusing the forestay. Add proper headsail trim to the mix and you can move the CE of the sailplan several feet fore or aft if you wanted to. Too easy. Excessive heel is a little more tricky. Let's start with the underwater hull shape. An exessively heeled hull has an unbalanced underwater shape. The water flowing over it creates forces that are also unbalanced. In small doses, unbalanced forces are good...they contribute to the hydrodynamic lift that helps to lift the boat to windward and opposes leeway. However, too much force causes the boat to round up. At high heel angles, the rudder also forces the bow down into the water (against the buoyancy) instead of turning it away from the wind, This is very ineffective. Here's the other source of heel-induced weather helm. On the average boat, the CE is about 1/3 the mast height above the deck, or about 1/2 the distance from the water to the masthead. That's about 15 to 20 feet. However, the CLR is only a few feet below the waterline. When the boat heels excessively, the CE and the driving force on the sails both move OUTBOARD relative to the CLR. The driving force and the horizontal offest outboard of the CLR create a turning moment that tries to turn the bow up into the wind....weather helm. Heavy, full-keeled boats (which don't heel much and are hard to turn anyway) and racing boats (which are designed to be sailed flat by crew hiking out hard) aren't really affected. However, modern, light, fin-keeled cruising boats with very little underwater surface are highly susceptible to weather helm caused by excessive heel. The next time you have too much weather helm, try depowering the main and see what happens. Then try reducing heel by hiking or shifting weight below to the windward side of the boat without depowering the main. You may be surprised. Peter H23 "Raven"
Blaming weather helm on mast rake
- Thread starter Wanderer138
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Thanks Peter
I've been reading so much about make rake and bend on this forum, and thank you for your analysis, for those of us who have telephone poles for masts, like most Catalinas. Reef, and learn how to sail. Thanks again for reviewing it so thoroughly. Stu
I've been reading so much about make rake and bend on this forum, and thank you for your analysis, for those of us who have telephone poles for masts, like most Catalinas. Reef, and learn how to sail. Thanks again for reviewing it so thoroughly. Stu
Exactly....
There's no question that moving CE forward reduces weather helm. The thing that gets overlooked is that it's a $100 solution to a $10 problem. Reef, for heaven's sake. We won't think you're a girly-man.
There's no question that moving CE forward reduces weather helm. The thing that gets overlooked is that it's a $100 solution to a $10 problem. Reef, for heaven's sake. We won't think you're a girly-man.
Ironically enough . . .for Stu Jackson
I discovered the link between excessive heel and the CE moving outboard while sailing a Catalina 30! We had chartered it for a weekend of ocean sailing in St Augustine. It was windy and we were sailing downwind under the roller-furling headsail only (I was being lazy). We turned onto a broad reach and sheeted in. The boat heeled way over and I was amazed at the amount of weather helm; the exact opposite of what you would expect. I turned into the wind, doused the headsail and raised the main to the first reef point. Much better and near-neutral helm. It took me a while to figure it all out. Peter H23 "Raven"
I discovered the link between excessive heel and the CE moving outboard while sailing a Catalina 30! We had chartered it for a weekend of ocean sailing in St Augustine. It was windy and we were sailing downwind under the roller-furling headsail only (I was being lazy). We turned onto a broad reach and sheeted in. The boat heeled way over and I was amazed at the amount of weather helm; the exact opposite of what you would expect. I turned into the wind, doused the headsail and raised the main to the first reef point. Much better and near-neutral helm. It took me a while to figure it all out. Peter H23 "Raven"
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