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Sustained 15-20 gusting to 35

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Steve Milby
Past Commodore

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USA
5851 Posts

Response Posted - 04/11/2014 : 07:24:05

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by dlucier
 Weatherhelm is not so much the pressure one feels on the tiller (those with wheels may feel little to nothing) but how many degrees off center one must position the rudder to counteract the boats tendency to turn to weather in order to maintain a straight line course. Anecdotal evidence from past forum posts suggests that in relatively identical conditions, the balanced rudder significantly reduces the amount one must position the rudder off center in order to maintain a straight line course when going to weather.
<hr height="1" noshade id="quote"></blockquote id="quote">
Heavy weather helm is caused by an imbalance of all the forces that are acting on the boat as it moves through the water.

One of the principal causes of that imbalance is the improper tuning of the rig. If the mast is raked too far aft, it causes an imbalance in the forces forward and aft of the center of lateral resistance (CLR), and you have to apply some tiller pressure to counteract the tendency of the boat to head up into the wind.

Another principal cause of that imbalance is excessive heeling. As the boat heels, the shape of the hull that is immersed in the water changes. It becomes assymetrical. When the boat is upright, the shape is perfectly symmetrical. The underwater surfaces are identically shaped on both sides. When it heels, the difference in the shape of the underwater surfaces results in more drag on one side of the boat than the other side, and that imbalance causes the boat to tend to point into the wind.

A third principal cause of weather helm is an imbalance resulting from poor sail trim. The mainsail is positioned aft of the CLR. (The CLR is the central point around which the boat pivots.) Pressure on the mainsail, aft of the CLR, causes the boat to tend to vane into the wind. The jib is situated forward of the CLR, and the pressures on it counteract the forces on the mainsail, and tend to pull the bow of the boat too leeward. If the pressures aft of the CLR are excessive, the boat tends to vane into the wind. The ideal is to achieve a balance between those forces by good sail selection and sail trim.

When any of those forces are out of balance, then you need to overcome them by turning the rudder slightly to hold the boat on course. Whenever you turn the rudder, you create drag, and on a sailboat, drag is similar to driving your car with your foot riding on the brake pedal all the time. It slows the boat down. The greater the imbalance, the more rudder is required to hold the boat on course, and the more drag is created. Excessive drag prevents the boat from achieving its optimum speed, and that, in turn, prevents it from pointing as high as it can. Balancing all those forces makes the boat foot faster and point higher. The rudder doesn't do anything to eliminate those imbalances. It overcomes them. A balanced rudder doesn't change the effect of all those imbalances. All it does is masks the effect by reducing the amount of force that you must use on the tiller to hold the boat on its course. When the problem is being caused by an imbalance in those forces, it makes more sense to me to eliminate the imbalance than to overcome it with a rudder that masks the problem. If you don't reduce that imbalance, then it takes the same amount of rudder to counteract those forces, regardless of whether the rudder is a balanced or unbalanced one. The only difference is that it feels like you are using less rudder with a balanced rudder.

By definition, "...weather helm is the tendency of sailing vessels to turn towards the source of wind, creating an unbalanced helm that requires pulling the tiller to windward [pressure] in order to counteract the effect." (wikipedia)

The conventional wisdom is that a little weather helm is a good thing, and I agree with that, but I believe that the ideal is to minimize weather helm as much as possible. It's a joy to sail a boat that has a very light helm, even in strong winds, and that can be achieved by balancing all those forces, and it doesn't cost anything to do it.

Edited by - Steve Milby on 04/11/2014 07:34:44

islander
Master Marine Consultant

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USA
3992 Posts

Response Posted - 04/11/2014 : 07:48:17

<blockquote id="quote">quote:<hr height="1" noshade id="quote">the forces are gonna go somewhere. I suspect they end up on that pintle<hr height="1" noshade id="quote"></blockquote id="quote">
Ya think?

Edited by - on

redeye
Master Marine Consultant

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3474 Posts

Response Posted - 04/11/2014 : 08:21:09

So they might want to beef up that strap with the balanced rudder. I had to beef up my alum plates on the sides of the tiller when I first got my boat. On our lake I sail in a lot of storm fronts.

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redeye
Master Marine Consultant

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3474 Posts

Response Posted - 04/11/2014 : 09:13:23

Here... That'll fix it...

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Davy J
Master Marine Consultant

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USA
1511 Posts

Response Posted - 04/11/2014 : 09:34:25

Good grief, is that an attempt to add brakes to a sailboat?????

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dlucier
Master Marine Consultant

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Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 04/11/2014 : 12:00:51

Without question, adjustments can be made to compensate for excessive weatherhelm no matter if the rudder is a computer designed, carbon fiber masterpiece or part of an old barn door hanging from the stern. The question is, does the newer rudder improve performance in such a way to lessen the amount of compensation required in relatively the same conditions?

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redeye
Master Marine Consultant

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Response Posted - 04/11/2014 : 12:23:31

<< The question is, >>

No question the newer balanced rudder is a great improvement. ( just be aware of the stresses )

Steve's point is regardless of rudder, balance the boat.

and well stated how to do that...

<< such a way to lessen the amount of compensation required >>

I don't think it does that, but rather makes it easier to make that compensation.

Edited by - redeye on 04/11/2014 12:27:03

Steve Milby
Past Commodore

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USA
5851 Posts

Response Posted - 04/11/2014 : 12:36:12

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by dlucier
 Without question, adjustments can be made to compensate for excessive weatherhelm no matter if the rudder is a computer designed, carbon fiber masterpiece or part of an old barn door hanging from the stern. The question is, does the newer rudder improve performance in such a way to lessen the amount of compensation required in relatively the same conditions?

<hr height="1" noshade id="quote"></blockquote id="quote">IMO, no. Bear in mind that the cause of an excessive weather helm is an imbalance in the forces that are acting on the boat as it moves through the water. The causes of those imbalances are bad sail trim, bad rig tuning and excessive heeling. The only way you can reduce weather helm is to reduce it's causes. Changing to a balanced rudder doesn't correct bad sail trim, or bad rig tuning or excessive heeling. All it does is reduce the amount of pressure that you feel when you are holding the tiller. A balanced rudder is a relatively innocuous way of masking weather helm, but, IMO it doesn't improve the performance of the boat. The best way to improve the performance of the boat is to improve your sail trim and rig tuning, and reduce excessive heeling. If you improve those things, then your boat will have a nice, comfortable weather helm, and you won't feel a need for a balanced rudder. All the design elements of the whole boat will be in balance.

Edited by - Steve Milby on 04/11/2014 12:47:33

DavidBuoy
Admiral

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USA
707 Posts

Response Posted - 04/11/2014 : 13:27:05

Personally, I was trying to salvage my old unbalanced rudder and finally came to the conclusion that it was toast. After that I had the option of different rudder designs for the boat. The fact that I am teaching my long time girlfriend how to sail and getting her into the hobby played a big part in my decision. The more comfortable/enjoyable I can make it for her, the more likely she will become a long-time sailor, and the more outings I will get with her. I've sailed since i was very young and when I was actually able to talk her into getting a sailboat vs. a powerboat I was shocked. I owed it to her to go for the balanced rudder! :)

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Steve Milby
Past Commodore

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USA
5851 Posts

Response Posted - 04/11/2014 : 14:07:10

There's nothing wrong with a balanced rudder. They're very popular. In fact, there may come a time when the old style rudder will not even be available anymore. My point is that if you're a golfer, and you buy a $500. driver, thinking it will improve your drives, it probably won't. You will improve your drives by improving the mechanics of your swing. The same is true of sailing.

If you buy a balanced rudder because your old one is deteriorated, then you're putting your money to good use. If, however, you buy a balanced rudder in the hope that it will significantly improve the performance of the boat, IMO, it won't.

I think the members of the forum should know what they can realistically expect to get if they spend several hundred dollars of their savings on a balanced rudder. They can expect a structurally sound rudder that will give a light feel to the tiller, but they shouldn't expect any appreciable improvement in the boat's performance. They will improve the boat's performance by improving the mechanics of their sail trimming and rig tuning. Anyone who has an old rudder that is still in serviceable condition should count himself blessed.

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cshaw
Captain

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USA
460 Posts

Response Posted - 04/11/2014 : 18:53:17

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by redeye
 << Not sure the forces on the lower pintle would be changed >>

Hmmm.. well if I hafta pull like hell with one rudder... and another goes over easy, the forces are gonna go somewhere. I suspect they end up on that pintle as the blade more easily positions itself perpendicular to the rushing water. The ease of use allows us to create greater force on that point. If the area in front and behind was "balanced" it could turn perpendicular, and probably snap right off.
<hr height="1" noshade id="quote"></blockquote id="quote">

I see what you mean. Good example with the pivot in the middle. OK, I agree!!! Thanks!

Chuck

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Stinkpotter
Master Marine Consultant

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Djibouti
9013 Posts

Response Posted - 04/12/2014 : 11:31:04

Conventional wisdom applied to rudder designs that I've read has been 15% forward of the pivot line (85% aft). That apparently provides the desired "power steering" while insuring that the rudder still wants to remain centered rather than flipping sideways (as it would at 50-50).

Edited by - Stinkpotter on 04/12/2014 11:31:36

redeye
Master Marine Consultant

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3474 Posts

Response Posted - 04/14/2014 : 10:57:25

<<< My Advice for what it's worth.. My rudder snapped in half between the pintles while sailing in the San Francisco Bay. The rudder is a balanced rudder and looked in very good condition. Only had a 2 hp motor and a 4 knot current blowing against us. >>>

From another thread, not mme...

Hmm...

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