I agree, currently it looks like it would turn into the wind a bit but there are a few ways to correct this. 1 is to loosen the back stay so the offset mast leans forward more, or, you could increase aspect ratio of the sail and shorten the boom, or you could make the Lee float asymmetric.
@@markpalmquist Big rudders, hull asymmetry are solutions, yet they increase turbulence and drag. On the other hand moving CE is truly the best way. If not possible, appendages, or hull shape can move CLR, understood. The question is, can you move your luff ahead and still shunt, or will it bump into the mast? Otherwise, how much are you willing to move the sail towards the Ama?? I like it, I just know how annoying excessive weather helm is, and how small hulls battle in light winds, the ugly ripples appendages add... Good Luck Mark, love your style! Keep Shunting mate Balkan Shipyards
@@BalkanShipyards thanks! I have learned a lot from watching your videos and also Vlad. I agree the best way to maintain helm balance is with sail's placement. Because I need distance between the sail and the skimming outrigger I have moved the sail more central which also allows me to move it slightly backwards because the CE moves along a diagonal line. but I agree it still appears to be behind the center of the hull's lateral resistance. I think making the smaller ama asymmetric in this case will be fine because it has a slightly higher aspect ratio than a longer hull would have, so it might be more efficient at turning fluid downwind and helping to resist leeway. But I am not sure. The ideal situation is no rudders at all but leaning sail forward or aft for directional control but that might be tricky. I might need 2 winches, 1 on each side.
@@markpalmquist I hope it works Mark, Good Luck! If leaning the sail is achieved by canting the mast, probably a block and tackle would be enough, could be easily done with double or triple blocks with a cam cleat, you would probably need much less than half a meter of block and tackle at the bottom end of the backstay...
I have recently been sailing my proa with a sail like this, but i have the tack right at the bow. But on the other hand, this is atlantic mode so the ama is pressing in and that might create leehelm. Im not really sure what will happen but also the hydronamic effects for leeway resistance dont take effect until water is flowing past the hull, that is, you are sailing, but aerodynamic effects start when the wind is blowing and the boat is stationary. Also when the boat is stationary, forces will cause it to rotate around its center of mass... so i am in the CoE-forward school of proa design. Anyway, i am looking forward to see how this performs!
The center of effort always acts on a diagonal line across the boat. So when you move the sail towards the windward hull, as I have done, it must also move backwards, otherwise it is no longer on the diagonal line. People get confused when they break the sail's force into heeling and pitching. Both happen at the same time, that is why the CE is a diagonal line. It acts perpendicular to your sail and through the center of lateral resistance. So that is why Atlantic proas have their sails farther to the back. But the correct place for a Pacific proa sail is closer to the front. Think of a person being pulled by a kite. If the kite string was not in front of them, there would be no forward force, so the kite sail is also both in front of the direction and downwind of the direction (diagonal line) and the force of the kite sail goes through the kite string. It is no different with a conventional sail going perpendicular to the boom.
@@markgallagher1376 because the hulls are both skinny they will sink about 5”. The sharp chine should provide enough leeward resistance but I could always add a leeboards if needed.
@@dominictarrsailing currently the hulls are 12 to 1 fineness. and the main is exactly twice the length of the leeward float which only has to keep the hydroplanes above the water until the boat hits about 7 knots, then the dynamic lift takes over.
It looks interesting, but it is still advisable to shift the sail center a little forward when changing tack.
I agree, more mast tilt and a taller mast to hold the yard higher, and push the sail forward. Yet very cool!
Keep Shunting, Balkan Shipyards
I agree, currently it looks like it would turn into the wind a bit but there are a few ways to correct this. 1 is to loosen the back stay so the offset mast leans forward more, or, you could increase aspect ratio of the sail and shorten the boom, or you could make the Lee float asymmetric.
@@markpalmquist Big rudders, hull asymmetry are solutions, yet they increase turbulence and drag. On the other hand moving CE is truly the best way. If not possible, appendages, or hull shape can move CLR, understood.
The question is, can you move your luff ahead and still shunt, or will it bump into the mast? Otherwise, how much are you willing to move the sail towards the Ama??
I like it, I just know how annoying excessive weather helm is, and how small hulls battle in light winds, the ugly ripples appendages add...
Good Luck Mark, love your style!
Keep Shunting mate
Balkan Shipyards
@@BalkanShipyards thanks! I have learned a lot from watching your videos and also Vlad. I agree the best way to maintain helm balance is with sail's placement. Because I need distance between the sail and the skimming outrigger I have moved the sail more central which also allows me to move it slightly backwards because the CE moves along a diagonal line. but I agree it still appears to be behind the center of the hull's lateral resistance. I think making the smaller ama asymmetric in this case will be fine because it has a slightly higher aspect ratio than a longer hull would have, so it might be more efficient at turning fluid downwind and helping to resist leeway. But I am not sure. The ideal situation is no rudders at all but leaning sail forward or aft for directional control but that might be tricky. I might need 2 winches, 1 on each side.
@@markpalmquist I hope it works Mark, Good Luck!
If leaning the sail is achieved by canting the mast, probably a block and tackle would be enough, could be easily done with double or triple blocks with a cam cleat, you would probably need much less than half a meter of block and tackle at the bottom end of the backstay...
I have recently been sailing my proa with a sail like this, but i have the tack right at the bow. But on the other hand, this is atlantic mode so the ama is pressing in and that might create leehelm. Im not really sure what will happen but also the hydronamic effects for leeway resistance dont take effect until water is flowing past the hull, that is, you are sailing, but aerodynamic effects start when the wind is blowing and the boat is stationary. Also when the boat is stationary, forces will cause it to rotate around its center of mass... so i am in the CoE-forward school of proa design. Anyway, i am looking forward to see how this performs!
The center of effort always acts on a diagonal line across the boat. So when you move the sail towards the windward hull, as I have done, it must also move backwards, otherwise it is no longer on the diagonal line. People get confused when they break the sail's force into heeling and pitching. Both happen at the same time, that is why the CE is a diagonal line. It acts perpendicular to your sail and through the center of lateral resistance. So that is why Atlantic proas have their sails farther to the back. But the correct place for a Pacific proa sail is closer to the front. Think of a person being pulled by a kite. If the kite string was not in front of them, there would be no forward force, so the kite sail is also both in front of the direction and downwind of the direction (diagonal line) and the force of the kite sail goes through the kite string. It is no different with a conventional sail going perpendicular to the boom.
Does it need a Lee board or dagger board or is the flat side of the amma going to resist leeway?
@@markgallagher1376 because the hulls are both skinny they will sink about 5”. The sharp chine should provide enough leeward resistance but I could always add a leeboards if needed.
@@markpalmquistwhat hull ratio are the hulls?
@@dominictarrsailing currently the hulls are 12 to 1 fineness. and the main is exactly twice the length of the leeward float which only has to keep the hydroplanes above the water until the boat hits about 7 knots, then the dynamic lift takes over.