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26-05-2019, 19:09 | #83 |
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Join Date: Oct 2014
Posts: 7,772
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Re: Why is my boat pointing into the wind?
Lets try this link to the fabrication of a rudder like yours as just a copy of the link instead of an embed to the forum. Here goes nothing or something.
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27-05-2019, 08:30 | #84 |
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Join Date: Dec 2012
Location: New Orleans
Boat: Bruce Roberts 44 Ofshore
Posts: 2,922
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Re: Why is my boat pointing into the wind?
Okay as nontechnical as possible, here is how it is. Assuming the steering system is working properly and the rudder is under complete control. If you only have a jib up, and no main, the boat will tend to fall off the wind. The front of the boat is pushed downwind but the back of the boat, not so much. Now reverse this. Lets say you have only the mainsail up. Assuming a sloop, that is, two triangular sails, one forward of the mast and one aft of the mast. With only the main, the sail aft of the mast up, and no jib, or sail forward of the mast, the stern will be pushed downwind and so the boat will want to point up into the wind. But if you have a small jib, not so bad. If you have a bigger jib, even better. If the jib is big enough and far enough forward to balance out the sideways force applied to the boat by the mainsail, the boat will be in balance. As the boat is blown downwind, the hull and keel and to a lesser extent the rudder and prop and any underwater features of the hull will offer resistance to this sideways push downwind, but will not oppose forward motion very much. The entire boat below the waterline is resisting sideways motion and the center of this resistance is important. You don't have to know exactly where it is, only that it is there. The center of effort of the sails needs to be very close to the center of resistance of the hull and its appendages underwater. If the center of effort is aft of the center of resistance, the stern is blown downwind more, and the bow points upwind. If the center of effort of the sails is forward of the center of resistance to the water, then the bow is blown more downwind and so the boat falls off the wind.
It is not simply a matter of how many square feet of sail are forward or aft of the center of resistance. Nor is it a simple matter of how many square feet of hull profile are forward or aft of the center of effort. The shape of the sails and of the hull and rudder have a big influence on where these two centers are. How flat or bellied the sails are, can make a tremendous difference. How close and how tight the clew, that is, the bottom aft corner of the sail that has the sheet (the line that controls the sail) is pulled aft and toward the centerline of the boat, plays a part, too. Also, how close the boat is already sailing toward the wind makes a difference. You have tried the obvious things to correct your weather helm, which is the tendency to round up into the wind. Now it is time to try the not so obvious things. Assuming that the rudder post is not bent. Yes, that is a thing. No, you won't always notice it by eye or by feel. Moving the bottom of the rudder forward or aft just an inch or two can make a big difference. Boats that have apparently survived a hard grounding often have a bent rudder post, as an example. Picture the boat running aground and you can see how it could happen. Or backing hard into an underwater obstruction. Starting with a nice clean hull is a good idea, in figuring this out. Clean the bottom, either in the water or hauled out. A haulout is nice actually, in that you can more easily visually inspect the boat more effectively. As sails age, their shape can change considerably. If you have been putting off having a new mainsail made, maybe it is time to give it some renewed interest. You may have other lines that can be used to control your sail shape. A Cunningham, a vang, an outhaul, etc. I will let you goggle those terms. A sail that draws poorly will have a different sideways effort than one that draws well. If your boat has what is called a fractional rig, you can get the center of effort to move forward a few inches by converting to a masthead rig. With a masthead rig, the forestay that the jib is on, is attached to somwehere near the top of the mast. With a fractional rig, the top end of the forestay attaches to the mast at some lower point, that is, maybe 75% of the way to the top of the mast. Keep in mind that there are reasons for having a fractional rig. For one thing, you can change the bend of the mast by changing the tension of forestay and backstays. This can change sail shape. If you can't be bothered with all that, then you aren't losing anything by going to a masthead rig. It will present more jib forward of the mast. So many ways have been discussed already, to get the center of effort to move forward. The easiest is of course adjusting sail trim while under sail. This is a routine adjustment. A normal part of sailing the boat. Adjustment to the mast position is next. Slack the backstays, and tighten the forestay, Slack and retighten the shrouds, which are the wires that go down to the deck on port and starboard sides of the mast, Make sure the mast is centered. Don't overtighten. Your wires don't have to be tight like banjo strings. Just not slack. Anyway obviously by moving the top of the mast forward a foot, you will be moving the center of the sail area forward a few inches. What kind of jib do you have? Is it a great big genoa, or a tight little triangle that barely touches the mast when you tack? Is it on a roller furler, or just clipped to the forestay? A big genoa that extends far aft can have the effect of shifting the center of effort aft. A jib that is too small for the main will do the same thing. A lot of lazy sailors will keep a big genoa on a roller furler and deploy however much it takes to sail the boat properly. Sloppy, but it works. I once bought an old open sand lighter in Belize for $100USD that was probably at least 70 years old. Originally it had a bowsprit but it had been broken off. When I bought it the boat was quite unmanageable on many points of sail. The mast had been restepped well forward but carried no headsail. I restepped the mast well aft, further aft than the original step, and sewed up a jib. A little experimenting and I had the boat self steering from broad reach to nearly close hauled. The tiller often stayed lashed down for hours, and steering was done with the mainsheet. I could have just gone below, except that there was no "below" haha. Had a lot of fun with that simple little boat that was such a PITA to keep off the wind when I first bought it. With this boat, the cure for weather helm was pretty obvious, but it still illustrates the physics of making a boat sail manageably and efficiently. So your job will be first to find what might have changed in the boat's configuration that could be contributing to this problem. Could be something subtle, like a mainsail that is blown out of shape from lots of hard use. Maybe someone without a lot of knowledge or even any thought, tightened up a loose backstay when in reality the forestay should have been tightened. If you can find what has changed then you can simply correct it. Otherwise you are looking at some sort of reconfiguration. Raking the mast forward (slacking backstay and tightening forestay to slant the top of the mast forward) could be your answer. Does the mainsail by chance have pockets for battens? Battens are wood or fiberglass slats that slide into pockets and stiffen or flatten a sail. Battens missing? Sail shape is changed. But now let's reexamine the possibility of a steering system malfunction. First of all I will make an assumption, that your steering is by quadrant and cable to chain and sprocket. A quadrant is a thing shaped like a pie slice, a very generous pie slice, the sort of slice I would cut for myself LOL. Properly speaking, a quarter of the pie. In practice, posibly more, possibly less. The point of the pie slice is attached to the rudder post. Where this attachment is, you should make a mark on quadrant and a mark on rudder post, so that you can see if the alignment shifts even a fraction of a degree. Make another very prominent mark exactly front and center on the rudder post with the rudder verified to be centered. Verified as in diving down and looking at it, not guessing. A VERY prominent mark, so you can look down in the lazarette and see your rudder position. You can mark your wheel, but the mark only tells you where the wheel is, not the rudder. If there is an emergency tiller then you can install it, or better yet make a cut down one, to serve as a rudder angle indicator. The first goal since you know for a fact that the rudder is well secured to the rudder post, is to make sure that the rudder post does not move out of alignment with the quadrant. The next thing is to make sure that the steering cables do not slip on the rim of the quadrant. With a small marlinspike, open up the cable near the quadrant's outer corners and insert a marker such as a small piece of rope. Cut off the ends so they don't catch in stuff. Remember how far they are from the quadrant corner with the rudder hard over. Next, look to the chain where it passes over the steering sprocket, make sure that the sprocket cannot turn even when considerable force is applied to it. For good measure, scratch a deep mark in the sprocket and in the shaft so you can see if the sprocket has turned on the shaft even a fraction of a degree. Your sprocket might not be securely keyed to the shaft. Then see to the wheel itself. Is it securely keyed to the shaft? Mark it, and check it often, especially before you leave the dock and after any incident. I also like to put a turks head at the top center spoke when the rudder is centered, as a visual marker. The important thing to watch is the rudder angle as indicated by the emergency tiller or substitute, if there is one, or some indicating mark down below, otherwise, versus the position of the wheel. TOTALLY ELIMINATE the possibility of a steering malfunction before doing anything drastic. You can do this. Weather (or sometimes lee) helm is a common problem and one that every sailor has to face and fix at some point. Oh, one more thing. When close hauled, that is sailing very close to the wind, sometimes it helps to run the jib sheet inboard of the shrounds. Especially on a very beamy boat in light airs.
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GrowleyMonster 1979 Bruce Roberts Offshore 44, BRUTE FORCE |
31-05-2019, 09:00 | #85 |
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Join Date: Aug 2015
Location: Cleveland, OH
Boat: Beneteau 331 34'
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Re: Why is my boat pointing into the wind?
This might be helpful: https://www.amazon.com/Illustrated-S...s%2C142&sr=8-1
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31-05-2019, 09:11 | #86 | |
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Location: Gloucester, MA USA
Boat: Newick Creative trimaran, 42'
Posts: 243
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Re: Why is my boat pointing into the wind?
Quote:
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31-05-2019, 10:17 | #87 |
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Join Date: Aug 2018
Posts: 10
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Re: Why is my boat pointing into the wind?
My expertise is dinghy sailing, which is all about sail balance. I read through the replies and have some comments.
First, the intermittent loss of control sounds exactly like what happened on a friend's boat in which the tiller attachment to the rudder post became just a little bit loose and would silently give way when stressed. Second, it is real common for people to tolerate a constant low level of weather helm in a cruising boat. When I race my dinghy, my goal is to sail it with the tiller centered as much as possible. The slightest weather helm is detectable by an inch or so of tiller being held to windward to hold a steady course. The rudder deflection causes a noticeable cut in boat speed and point. I try to remove that by sail and hull trim and moving the centerboard a little bit. Baggy old sails can make it really hard to balance my dinghy, so I buy new sails on a regular basis. Keelboat cruisers, include me when I do that, don't work so hard to remove that last little bit of weather helm, so my guess is that you sail with a little bit of weather helm all the time. Anyway, it may be that a slip at your rudder post manifests itself when your residual weather help ooches over a threshhold. I saw exactly that in somebody else's boat years ago. Mike. |
31-05-2019, 10:26 | #88 |
Marine Service Provider
Join Date: Feb 2012
Location: Kauai Hawaii
Boat: home built 31' Hartley Tasman
Posts: 309
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Re: Why is my boat pointing into the wind?
I had similar issues where I had a lot of weather helm, the rudder becomes overwhelmed and the boat's nose was forced upwind...
it is a sign that your sail balance is out...In some cases raking your mast aft will bring the center of effort behind a bit and ease the pressure on the rudder, or if you can reposition the heel of your mast further aft, some of the deck to mast boots have an option to move fore or aft...try reefing your mainsail one position and increase your jib or genoa size... I installed a lovely 6 foot bowsprit to move my COE forward and I have no more problems I have described this in detail in my book. Good luck... |
31-05-2019, 10:35 | #89 |
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Join Date: Aug 2006
Location: Skagit City, WA
Posts: 25,747
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Re: Why is my boat pointing into the wind?
My guess is it's sail trim. I had a boat early in my sailing career that the steering cable actually broke loose due to the same thing.... I could not turn the boat down on a close reach! That boat had a huge rudder too. I don't know now 40 years later, but I suspect it was my inability to sail trim properly.
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31-05-2019, 11:58 | #90 |
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Join Date: Dec 2011
Posts: 26
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Re: Why is my boat pointing into the wind?
Maybe it's a rudder problem? Perhaps the shaft spins inside the rudder when under pressure, then finds its position again due to something inside acting as a detent. Or perhaps it is the quadrant that slipped its key and is spinning on the shaft? Or maybe something inside the binnacle causing the gear to slip (though it seems highly unlikely).
Question: did you mark the wheel for center? Is it always centered when motoring straight, especially after one of these "auto-tacks"? |
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