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DaveC426913
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This is a practical issue I've trying to resolve by understanding the physics. While I talk sailing jargon, ultimately this is a question of simple torsional forces on a body.
So: In a high wind, when heeled over, my boat does what's called "rounding up"; it turns sharply into the wind - despite rudder hard over to stop it - and stalls.
Granted, this is a good safety failsafe, automatically preventing the boat from being knocked down. But it is not always desirable. It should not occur when the boat is controlled (actively being prevented from doing so). It definitely should not occur when I have only the foresail up. Mainsail is completely doused. That essentially puts all the force forward, meaning there is no way the boat should be able to turn toward the wind.
Naively viewed, if all force is forward of the point of rotation (the keel) there should be no way for it to turn toward the force.I'm in discussions with sailors and one of the suggestions is that a giant sail (Genoa 150%) extends well aft of the keel, almost to the cockpit, this means there is force on the stern of the boat (the cleat, abeam of the cockpit), pushing the stern downwind.
So the suggestion is to take in enough foresail so that the aft edge of the sail does not go aft of the keel.
I've drawn a diagram, and I think, in doing so, I see why this is the case. I want to confirm.
What's giving me doubts is that the sail area has been moved forward, but the cleat (the point of attachment at which the boat is physically pulled through the water) has not moved forward.
I was thinking this causes the whole boat to act as a single, solid structure, and it should not matter where you attach the line/cleat.
But if I am to believe my diagram, I see that the distance from point of rotation to point of force is shorter, therefore - like a short-handled wrench versus a long-handled wrench - it provides less torque. Which is what I want.
So did I just confirm this bit of nautical wisdom?
So: In a high wind, when heeled over, my boat does what's called "rounding up"; it turns sharply into the wind - despite rudder hard over to stop it - and stalls.
Granted, this is a good safety failsafe, automatically preventing the boat from being knocked down. But it is not always desirable. It should not occur when the boat is controlled (actively being prevented from doing so). It definitely should not occur when I have only the foresail up. Mainsail is completely doused. That essentially puts all the force forward, meaning there is no way the boat should be able to turn toward the wind.
Naively viewed, if all force is forward of the point of rotation (the keel) there should be no way for it to turn toward the force.I'm in discussions with sailors and one of the suggestions is that a giant sail (Genoa 150%) extends well aft of the keel, almost to the cockpit, this means there is force on the stern of the boat (the cleat, abeam of the cockpit), pushing the stern downwind.
So the suggestion is to take in enough foresail so that the aft edge of the sail does not go aft of the keel.
I've drawn a diagram, and I think, in doing so, I see why this is the case. I want to confirm.
What's giving me doubts is that the sail area has been moved forward, but the cleat (the point of attachment at which the boat is physically pulled through the water) has not moved forward.
I was thinking this causes the whole boat to act as a single, solid structure, and it should not matter where you attach the line/cleat.
But if I am to believe my diagram, I see that the distance from point of rotation to point of force is shorter, therefore - like a short-handled wrench versus a long-handled wrench - it provides less torque. Which is what I want.
So did I just confirm this bit of nautical wisdom?
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