Don,I have a 1992 H 35.5 and would like to confirm I am taking all the right steps to reduce wether helm. The boat has a wing keel and a heavily raked mast and original sails. 1st point to confirm is that anything over 20 degrees of heel is counter productive, As the heel increases the weather helm increases and the required rudder angle acts as a brake. I tighten the genoa halyard and move the cars back to flatten the foresail and bring the sail in as tight as possible? I tighten the foot on the main and the main halyard. With the traveller slight below center I tighten the main sheet and boom vang (no cunningham) I also tension the backstay to help flatten both sails. If the wind builds and I am still heeled excessively I let out the main sheet and bring the traveller up to create twist. All of these adjustments in 15 knots true wind and I am still fighting weather helm - am I missing something? Are new sails the answer? I don't think I should need to reef in 15-20 knots wind? Your comments please, Thanks in advance
- Status
Sounds about right
It obviously depends on your point of sail but upwind in 15 - 20 knots of true wind don't forget you will actually have about 18 - 25 knots apparent. I have a '95 Hunter 35.5 and I usually take the first reef upwind at about 18 knots apparent. Any more than that the boat heels too much and as you said, the weather helm builds, and your speed actually slows. Also my sailing partner complains excessively which is VERY counter productive to enjoyable sailing! With the shallow draft keel the 35.5 is not a particularly stiff boat.
It obviously depends on your point of sail but upwind in 15 - 20 knots of true wind don't forget you will actually have about 18 - 25 knots apparent. I have a '95 Hunter 35.5 and I usually take the first reef upwind at about 18 knots apparent. Any more than that the boat heels too much and as you said, the weather helm builds, and your speed actually slows. Also my sailing partner complains excessively which is VERY counter productive to enjoyable sailing! With the shallow draft keel the 35.5 is not a particularly stiff boat.
Sail shape vs sail trim
While sail shape is a part of it the sail trim is the most important factor in controlling sail balance. REALLY understanding sail trim and balance requires an understanding of how a boat gets pushed through the water. How that apparently athwart ships or force from ahead can make the boat go forward. Once you get that down the heeling force is simple to understand. Lets get our bearings. Everything can be thought of as either a driving force, a twisting force or a heeling force or their underwater counterparts. All twisting forces act as if the keel is the "pivot point. Also get in the habit of thinking about the sail plan in two ways; from the side and as viewed from the overhead. Start with a simple example; going dead down wind DDW. With just the main up and all the way over to port the force on the sail will be pushing the boat forward and trying to twist it around the keel in a clockwise (CW)(as seen from above) direction. You counter this CW twisting force by pulling the tiller to starboard. Now going DDW there is no weather or lee side so lets turn 1 degree to starboard and now what do we have? Weather helm! I'm pulling the tiller "to weather" to balance the boat. To balance the sail trim so the boat wants to go straight on its own I'm going to have to come up with a sail force that causes CCW (counter clock wise) twisting. Hay! if I put the jib up and pole it out to starboard that would twist the boat around CCW. Broad reach- starboard tack; you have pulled the traveler up and taken the whisker pole off the jib which is now in its' normal position on the leeward side of the boat. The force from the main is trying to heel the boat and twist it CW around the keel while the force from the jib is trying to heel the boat and twist it CCW around the keel. So what is driving the boat on one of the fastest points of sail??? Well neither the main nor jib foot is parallel to the direction the boat is going. The actual sail force is pointed forward quite a bit because of this. So part of the force is forward and that drives the boat but part is athwart ships and that just causes heeling. So what I really want to do on a broad reach is to let the main and jib out as much as possible to get the sail force pointing forward with as little heeling force as possible. That works to a point where the sails start lufting and this is where sail shape is REALLY important. Getting those suckers to WORK once I've got their feet at the right angle!!! This also introduces another wrinkle, the main sail force is now pointed forward and to port and its' line of action passes behind the keel but in front of the rudder by a distance of several feet while the jib sail force is also to forward and port but its line of action is passing really close to the keel. This give the main sail force an additional advantage since it is "acting" at a greater distance from the keel (pivot). So even if both main and jib forces are the same strength and in the same direction the main will have more of an effect on the twisting of the boat around the keel. To fix this we can do one of three things, de-power the main or power up the jib or a little of both. Once again, we got the sail feet where we wanted them for driving force and then fixed the sail shape. If you where heeling to much then de-power the main as that will also decrease the overall heeling force. Going uphill, starboard tack; Similar arguments for sail trim and balance can be made when close hauled. The big difference is that now the forces are almost totally athwart ships with just a little bit of the force driving the boat. The new wrinkle here is to understand that the actual force a sail produces is not perpendicular to the line between the tack and clew. I can be made to point more toward the tack (this is good) by shaping the sail. A big powerful sail will have more forward (twards the tack) pointing force than a flat de-powered one. This is exactly the opposite of what you want when going into the wind as it means lots of heeling force and you can't point very high. So you would want to reef a little bit earlier even if the wind was exactly the same speed when going to windward just to keep the boat stood up straight and to keep the sails powered up. And lest you think I know what I'm doing, I read all this stuff in Chapman's Piloting. I can attest that it does work this way. I suggest you go out and try "crazy" things with the sails when the GPS is turned on and see what happens. It was quite satisfying when letting out the sails made the boat go 2 knots faster on a broad reach and stood her up and got rid of the weather helm too. Admiral happy, boat going fast, straight, and upright, wind in what is left of my hair, dog at my side and lunch coming. It don't get much better than that.
While sail shape is a part of it the sail trim is the most important factor in controlling sail balance. REALLY understanding sail trim and balance requires an understanding of how a boat gets pushed through the water. How that apparently athwart ships or force from ahead can make the boat go forward. Once you get that down the heeling force is simple to understand. Lets get our bearings. Everything can be thought of as either a driving force, a twisting force or a heeling force or their underwater counterparts. All twisting forces act as if the keel is the "pivot point. Also get in the habit of thinking about the sail plan in two ways; from the side and as viewed from the overhead. Start with a simple example; going dead down wind DDW. With just the main up and all the way over to port the force on the sail will be pushing the boat forward and trying to twist it around the keel in a clockwise (CW)(as seen from above) direction. You counter this CW twisting force by pulling the tiller to starboard. Now going DDW there is no weather or lee side so lets turn 1 degree to starboard and now what do we have? Weather helm! I'm pulling the tiller "to weather" to balance the boat. To balance the sail trim so the boat wants to go straight on its own I'm going to have to come up with a sail force that causes CCW (counter clock wise) twisting. Hay! if I put the jib up and pole it out to starboard that would twist the boat around CCW. Broad reach- starboard tack; you have pulled the traveler up and taken the whisker pole off the jib which is now in its' normal position on the leeward side of the boat. The force from the main is trying to heel the boat and twist it CW around the keel while the force from the jib is trying to heel the boat and twist it CCW around the keel. So what is driving the boat on one of the fastest points of sail??? Well neither the main nor jib foot is parallel to the direction the boat is going. The actual sail force is pointed forward quite a bit because of this. So part of the force is forward and that drives the boat but part is athwart ships and that just causes heeling. So what I really want to do on a broad reach is to let the main and jib out as much as possible to get the sail force pointing forward with as little heeling force as possible. That works to a point where the sails start lufting and this is where sail shape is REALLY important. Getting those suckers to WORK once I've got their feet at the right angle!!! This also introduces another wrinkle, the main sail force is now pointed forward and to port and its' line of action passes behind the keel but in front of the rudder by a distance of several feet while the jib sail force is also to forward and port but its line of action is passing really close to the keel. This give the main sail force an additional advantage since it is "acting" at a greater distance from the keel (pivot). So even if both main and jib forces are the same strength and in the same direction the main will have more of an effect on the twisting of the boat around the keel. To fix this we can do one of three things, de-power the main or power up the jib or a little of both. Once again, we got the sail feet where we wanted them for driving force and then fixed the sail shape. If you where heeling to much then de-power the main as that will also decrease the overall heeling force. Going uphill, starboard tack; Similar arguments for sail trim and balance can be made when close hauled. The big difference is that now the forces are almost totally athwart ships with just a little bit of the force driving the boat. The new wrinkle here is to understand that the actual force a sail produces is not perpendicular to the line between the tack and clew. I can be made to point more toward the tack (this is good) by shaping the sail. A big powerful sail will have more forward (twards the tack) pointing force than a flat de-powered one. This is exactly the opposite of what you want when going into the wind as it means lots of heeling force and you can't point very high. So you would want to reef a little bit earlier even if the wind was exactly the same speed when going to windward just to keep the boat stood up straight and to keep the sails powered up. And lest you think I know what I'm doing, I read all this stuff in Chapman's Piloting. I can attest that it does work this way. I suggest you go out and try "crazy" things with the sails when the GPS is turned on and see what happens. It was quite satisfying when letting out the sails made the boat go 2 knots faster on a broad reach and stood her up and got rid of the weather helm too. Admiral happy, boat going fast, straight, and upright, wind in what is left of my hair, dog at my side and lunch coming. It don't get much better than that.
Don
Let's start from the top. How much rake is "heavily raked"? Using 1% rake is a safe number. That would put your mast rake at 5.25". As rake increases, pointing gets higher but weather helm increases. Much of what you said from that point on is correct until you got to the part about "....If the wind builds and I am still heeled excessively I let out the main sheet and bring the traveler up to create twist." The traveler does not affect twist. It only controls angle of attack. Easing the main sheet will twist off the sail but bringing the traveler up only serves to counter the move you made with the sheet. Try lowering the traveler before you twist off the main. If helm is still a problem then ease main sheet but don't bring the traveler up. Additionally you should move the genoa lead cars back to twist off the top of the genoa and keep the sheet tight. This will also aid in reducing weather helm and heal.
Let's start from the top. How much rake is "heavily raked"? Using 1% rake is a safe number. That would put your mast rake at 5.25". As rake increases, pointing gets higher but weather helm increases. Much of what you said from that point on is correct until you got to the part about "....If the wind builds and I am still heeled excessively I let out the main sheet and bring the traveler up to create twist." The traveler does not affect twist. It only controls angle of attack. Easing the main sheet will twist off the sail but bringing the traveler up only serves to counter the move you made with the sheet. Try lowering the traveler before you twist off the main. If helm is still a problem then ease main sheet but don't bring the traveler up. Additionally you should move the genoa lead cars back to twist off the top of the genoa and keep the sheet tight. This will also aid in reducing weather helm and heal.
There a BIG difference between
15 kts and 20 kts. It constantly amazes me when people use this [wide] range, since most mid sized boats reprtedly (over the past 25 years) have mentioned in their own association websites that reefing is recommended at 18 kts. Drop the traveler, then loosen the mainsheet (which becomes a fisherman's reef) and if that doesn't work, throw in a reef.
15 kts and 20 kts. It constantly amazes me when people use this [wide] range, since most mid sized boats reprtedly (over the past 25 years) have mentioned in their own association websites that reefing is recommended at 18 kts. Drop the traveler, then loosen the mainsheet (which becomes a fisherman's reef) and if that doesn't work, throw in a reef.
At 20 kts. the wind is blowing with twice the
force as at 15 kts. The force changes as to the square of the velosity. If your boat reaches hull speed in 12 kts of wind then you are over canvased above 15kts. You are just adding horse power but not speed and just stressing the entire boat.
force as at 15 kts. The force changes as to the square of the velosity. If your boat reaches hull speed in 12 kts of wind then you are over canvased above 15kts. You are just adding horse power but not speed and just stressing the entire boat.
- Status