It’s raining this morning so I’m listening to music which is a good excuse to rant about something and I’m sick of politics. I just took a cruise over to the “All Discussions” forum and saw a post from the Beneteau forum, “Weather Helm” in which it was suggested by a couple of posters that mast rake was the first thing to look at. I hate to see that old chestnut whenever it appears and it’s apt to make the poor OP waste a lot of time fiddling with his rig to no detectable effect.
The whole rig balance subject is one of the most misunderstood in sailing. There is really no such thing. Reducing mast rake, thus moving the sail area slightly forward, will reduce the rudder angle; in theory. However, it would take very careful measurements and extreme care to be sure you hadn’t changed anything else to detect it.
The source of the whole rig balance myth has its roots in racing boat design. Races are won or lost on the last few percent of performance that cruisers couldn’t even detect without careful data recording or other vessels close along side. The racing boat designer wants to have an exact rudder angle in a specific condition, just before a sail area reduction or sail shape change is made. This angle will be enough to provide some lift to windward (that weather helm is pushing in the right direction, opposite leeway) and good steering feel but not so much as to create excess drag. The whole business of calculating the center of effort of the sail plan and comparing it with the geometric center of the sail plan is based on obtaining this exact rudder angle. It only works with a large data base of similar hulls, sails of known quality, and all other factors carefully controlled. The racing boat designer and owner care whether the rudder angle in this specific design condition is, say, 6 degrees instead of 5. It doesn’t matter one whit to the cruising sailor.
This whole lead calculation business has created the widespread belief (alive and well on SBO evidently) that there is a magic balance point. If the rig is exactly on the balance point, the boat will steer properly. Move the rig just slightly aft (too much mast rake) and the boat will have “weather helm” move it too far forward, and the boat will have “lee helm”. This is poppycock.
It is true that, all else being equal, moving the rig aft will increase rudder angle and moving it forward will reduce it. However, huge movements are required to create the kind of changes that would cause a cruising sailor to think of his boat as having or not having weather helm. Other factors are for more significant so that the amount of lead, which is slightly changed by mast rake, is simply a signal lost in the noise except under the carefully controlled conditions of racing boat design and tuning.
Need convincing? My boat has a strong weather helm. It was a lot more than I liked. I had a new set of sails built with a smaller jib. This, in theory, moved the center of the sail plan back which should have increased weather helm. Instead, helm force and angle were significantly reduced by the conversion from old, blown out, sails to those of proper shape. If the wind comes on hard and I’m struggling with strong helm forces and listening to the roar of water pouring over the top of the rudder at 15 – 20 degree angle, I can roll up the jib. The center of the sail plan has now been moved back a few feet and yet weather helm is reduced to almost nothing.
Heel is a major factor in weather helm. The drive of the sails is out to leeward and the drag of the hull is closer to windward. Whenever you have two offset forces, there will be a turning moment. Heeled hulls also tend to want to turn towards the high side due to the wedge of the leeward bow and other wave train effects. Rudder angle basically increases with heel if all else is kept constant. Dump your main so that it is doing almost nothing and rudder angle and helm force will decrease. This will have as much to do with heel reduction as it does with moving the center of effort of the rig several feet forward. Watch what happens if the wind keeps rising and you are forced back to the same large heel angle. Rudder force and angle will increase again. They will be less than with the full main but not by as much as the simplistic rig balance model would lead you to expect.
Speaking of angle and rudder force: much of the time when this subject is being kicked around in bars and Internet forums, no one knows which the other is talking about. It is possible to have very high helm forces and yet the rudder at exactly the optimum angle. This is a function of the steering system. Think of a boat with a very short tiller. It will take a lot of force to keep the rudder at even a small angle.
Weather helm is when the rudder is at such a large angle that the boat is slowed and the ability to make the boat go where you need it to go is compromised.
When someone with a standard boat like a Beneteau says they have weather helm, I suspect they aren’t steering the boat properly to windward. Excessive weather helm is the boat trying to tell you something. Heel is a major contributor to helm force and reefing is a lost art. People are commonly taught how to read jib tell tales but there are many of them sailing around doing it by rote without paying attention to heel. When the boat heels beyond its optimum angle, ease off on the helm pressure and forget what the tell tales look like. Let her up to the angle at which she was previously going well and the helm force will decrease. The trick is to do it very slowly without letting the boat start swinging. Think of it as a pressure reduction on the wheel or tiller instead of a steering motion.
If you are one of the many people who just strap the sails in and then keep your WindEx lined up with those stupid little indicators that come with them, forget it. You are going to think you have weather helm. When conditions are puffy and heel is large, the difference between having the boat going well and struggling with too much helm will be far too fine to identify with something on the masthead.
The basic technique for sailing to windward is very slow easing of pressure to let the natural weather helm bring the boat closer to the wind. You should just barely be able to see the bow swinging against the shore background or horizon. If there are waves, the bow should remain fixed against the background and just take a little nibble to windward at one point in the pitching cycle. You are trying to sneak up into the wind as slowly as possible. As soon as a windward tell tale breaks sharply upwards or you see a sudden slight decrease in the angle of the mast against the horizon, give the wheel or tiller an instant and decisive movement steering to leeward and hold it until the tell tale lays down and the boat takes hold again. Then resume the slow reduction of pressure to let the boat start working up again. The proper course to windward will be a zig zag with long shallow scallops to windward and quick turns back to leeward.
This assumes a steady wind. If conditions are gusty, you sail like this in the normal wind and then let the boat come up in the gusts so that the heel angle remains constant. Paying attention to the angle of the mast against the horizon is one of the best weather helm reduction methods there is. Of course, almost no one can use it now that everyone has full dodger and bimini outfits.
If your rudder angle is still too large in the wind between the gusts, it’s time for a sail area reduction. Reefing now uncommon but, if people practiced it more, they would be surprised at how often the boat speeds up when reefed. You’ll see this most reliably if you reef before the boat is over pressed. Most people put it off too long.
You might be interested in reading this article I wrote about sailing a big schooner to windward. I don’t sail Strider this way and you won’t be able to sail your boat exactly like this because the surface wind smaller boats sail in is simply more turbulent down near the water surface or near land. However, and understanding of the principles can help make you a better helmsman.
http://www.pointseast.com/template.shtml?id=EEuApppyplMkENKsEG&style=story
The whole rig balance subject is one of the most misunderstood in sailing. There is really no such thing. Reducing mast rake, thus moving the sail area slightly forward, will reduce the rudder angle; in theory. However, it would take very careful measurements and extreme care to be sure you hadn’t changed anything else to detect it.
The source of the whole rig balance myth has its roots in racing boat design. Races are won or lost on the last few percent of performance that cruisers couldn’t even detect without careful data recording or other vessels close along side. The racing boat designer wants to have an exact rudder angle in a specific condition, just before a sail area reduction or sail shape change is made. This angle will be enough to provide some lift to windward (that weather helm is pushing in the right direction, opposite leeway) and good steering feel but not so much as to create excess drag. The whole business of calculating the center of effort of the sail plan and comparing it with the geometric center of the sail plan is based on obtaining this exact rudder angle. It only works with a large data base of similar hulls, sails of known quality, and all other factors carefully controlled. The racing boat designer and owner care whether the rudder angle in this specific design condition is, say, 6 degrees instead of 5. It doesn’t matter one whit to the cruising sailor.
This whole lead calculation business has created the widespread belief (alive and well on SBO evidently) that there is a magic balance point. If the rig is exactly on the balance point, the boat will steer properly. Move the rig just slightly aft (too much mast rake) and the boat will have “weather helm” move it too far forward, and the boat will have “lee helm”. This is poppycock.
It is true that, all else being equal, moving the rig aft will increase rudder angle and moving it forward will reduce it. However, huge movements are required to create the kind of changes that would cause a cruising sailor to think of his boat as having or not having weather helm. Other factors are for more significant so that the amount of lead, which is slightly changed by mast rake, is simply a signal lost in the noise except under the carefully controlled conditions of racing boat design and tuning.
Need convincing? My boat has a strong weather helm. It was a lot more than I liked. I had a new set of sails built with a smaller jib. This, in theory, moved the center of the sail plan back which should have increased weather helm. Instead, helm force and angle were significantly reduced by the conversion from old, blown out, sails to those of proper shape. If the wind comes on hard and I’m struggling with strong helm forces and listening to the roar of water pouring over the top of the rudder at 15 – 20 degree angle, I can roll up the jib. The center of the sail plan has now been moved back a few feet and yet weather helm is reduced to almost nothing.
Heel is a major factor in weather helm. The drive of the sails is out to leeward and the drag of the hull is closer to windward. Whenever you have two offset forces, there will be a turning moment. Heeled hulls also tend to want to turn towards the high side due to the wedge of the leeward bow and other wave train effects. Rudder angle basically increases with heel if all else is kept constant. Dump your main so that it is doing almost nothing and rudder angle and helm force will decrease. This will have as much to do with heel reduction as it does with moving the center of effort of the rig several feet forward. Watch what happens if the wind keeps rising and you are forced back to the same large heel angle. Rudder force and angle will increase again. They will be less than with the full main but not by as much as the simplistic rig balance model would lead you to expect.
Speaking of angle and rudder force: much of the time when this subject is being kicked around in bars and Internet forums, no one knows which the other is talking about. It is possible to have very high helm forces and yet the rudder at exactly the optimum angle. This is a function of the steering system. Think of a boat with a very short tiller. It will take a lot of force to keep the rudder at even a small angle.
Weather helm is when the rudder is at such a large angle that the boat is slowed and the ability to make the boat go where you need it to go is compromised.
When someone with a standard boat like a Beneteau says they have weather helm, I suspect they aren’t steering the boat properly to windward. Excessive weather helm is the boat trying to tell you something. Heel is a major contributor to helm force and reefing is a lost art. People are commonly taught how to read jib tell tales but there are many of them sailing around doing it by rote without paying attention to heel. When the boat heels beyond its optimum angle, ease off on the helm pressure and forget what the tell tales look like. Let her up to the angle at which she was previously going well and the helm force will decrease. The trick is to do it very slowly without letting the boat start swinging. Think of it as a pressure reduction on the wheel or tiller instead of a steering motion.
If you are one of the many people who just strap the sails in and then keep your WindEx lined up with those stupid little indicators that come with them, forget it. You are going to think you have weather helm. When conditions are puffy and heel is large, the difference between having the boat going well and struggling with too much helm will be far too fine to identify with something on the masthead.
The basic technique for sailing to windward is very slow easing of pressure to let the natural weather helm bring the boat closer to the wind. You should just barely be able to see the bow swinging against the shore background or horizon. If there are waves, the bow should remain fixed against the background and just take a little nibble to windward at one point in the pitching cycle. You are trying to sneak up into the wind as slowly as possible. As soon as a windward tell tale breaks sharply upwards or you see a sudden slight decrease in the angle of the mast against the horizon, give the wheel or tiller an instant and decisive movement steering to leeward and hold it until the tell tale lays down and the boat takes hold again. Then resume the slow reduction of pressure to let the boat start working up again. The proper course to windward will be a zig zag with long shallow scallops to windward and quick turns back to leeward.
This assumes a steady wind. If conditions are gusty, you sail like this in the normal wind and then let the boat come up in the gusts so that the heel angle remains constant. Paying attention to the angle of the mast against the horizon is one of the best weather helm reduction methods there is. Of course, almost no one can use it now that everyone has full dodger and bimini outfits.
If your rudder angle is still too large in the wind between the gusts, it’s time for a sail area reduction. Reefing now uncommon but, if people practiced it more, they would be surprised at how often the boat speeds up when reefed. You’ll see this most reliably if you reef before the boat is over pressed. Most people put it off too long.
You might be interested in reading this article I wrote about sailing a big schooner to windward. I don’t sail Strider this way and you won’t be able to sail your boat exactly like this because the surface wind smaller boats sail in is simply more turbulent down near the water surface or near land. However, and understanding of the principles can help make you a better helmsman.
http://www.pointseast.com/template.shtml?id=EEuApppyplMkENKsEG&style=story
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