This may be a silly question but what is the preferred location of the car for the jib sheet in the jib sheet track which is located on the side deck. I have been leaving the car alone in all kinds of weather. (Car is located approx. in the center of the track.) I was reading an article and they said to move the car forward for light winds and back for heavy winds. What is a rule of thumb for its placement? Should I be looking at the tell tales on the jib and then adjust accordingly? Thanks, Ray
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Angle of pull
The car allows you to adjust the angle of pull the sheet has on the jib clew. Move the car forward and the pull is more downward which will tend to take the twist out of the sail and add camber. Move the car aft and the pull is more in line with the foot which allows the head to "twist off" and flattens the camber. Forward = power up, less twist, more camber used in light winds aft = power down, more twist, less camber used in higher winds. To point the highest you have to a) have the sheet as "inboard" as possible and b) the car as far aft as possible. Unless you are trying to point in choppy seas or in light winds in which case you will want to sacrifice some angle of sail for speed. This is where racers earn their money. Balancing the speed and angle of the boat with respect to the desired course for a VAST array of wind and sea conditions. I use the Newton method for lots of things to include car placement. Get the boat sailing upwind and going as fast as possible for a given course. Tweak each control in turn; Cunningham, sheet, leach cord, sheet car....... By remembering where the car was before the tweak and the speed then you can compare it to the new trim and speed to see if you did any good. if you got an increase then newtons method would tell you to move it more in the same direction until you see a decrease and then half the distance between the present position and the last one. You can take this kind of thing to several decimal places in the math world but practically speaking you are only talking about an inch or two of rope/car position so there is not much to do as you really can't adjust it (and tell the difference) when you only move the rope a millimeter. Then all you have to do is tweak all the other controls and since every thing interacts, start back at the beginning tweaking till EVERYTHING you do slows you down.
The car allows you to adjust the angle of pull the sheet has on the jib clew. Move the car forward and the pull is more downward which will tend to take the twist out of the sail and add camber. Move the car aft and the pull is more in line with the foot which allows the head to "twist off" and flattens the camber. Forward = power up, less twist, more camber used in light winds aft = power down, more twist, less camber used in higher winds. To point the highest you have to a) have the sheet as "inboard" as possible and b) the car as far aft as possible. Unless you are trying to point in choppy seas or in light winds in which case you will want to sacrifice some angle of sail for speed. This is where racers earn their money. Balancing the speed and angle of the boat with respect to the desired course for a VAST array of wind and sea conditions. I use the Newton method for lots of things to include car placement. Get the boat sailing upwind and going as fast as possible for a given course. Tweak each control in turn; Cunningham, sheet, leach cord, sheet car....... By remembering where the car was before the tweak and the speed then you can compare it to the new trim and speed to see if you did any good. if you got an increase then newtons method would tell you to move it more in the same direction until you see a decrease and then half the distance between the present position and the last one. You can take this kind of thing to several decimal places in the math world but practically speaking you are only talking about an inch or two of rope/car position so there is not much to do as you really can't adjust it (and tell the difference) when you only move the rope a millimeter. Then all you have to do is tweak all the other controls and since every thing interacts, start back at the beginning tweaking till EVERYTHING you do slows you down.
Ray
The simple answer is yes. Jib lead location has an enormous effect on the headsail performance. I would very strongly advise that you buy Don Guillette's book 'The Sail Trim Users Guide' which is available in the Chandlery on this site. It is the best $19.95 you will ever spend on your boat.
The simple answer is yes. Jib lead location has an enormous effect on the headsail performance. I would very strongly advise that you buy Don Guillette's book 'The Sail Trim Users Guide' which is available in the Chandlery on this site. It is the best $19.95 you will ever spend on your boat.
Check out this article
with special notice to the sixth paragraph http://www.sailjazz.com/editorial/read/31
with special notice to the sixth paragraph http://www.sailjazz.com/editorial/read/31
Position of Jib Car
In simplest terms, the car should be positioned such that the angle of the jib sheet (by sighting along it) makes it point to the center of the jib's luff. Michael
In simplest terms, the car should be positioned such that the angle of the jib sheet (by sighting along it) makes it point to the center of the jib's luff. Michael
tell tales
I was always taught the car is in the right position when all tell tales on the jib break at the same pointing angle.
I was always taught the car is in the right position when all tell tales on the jib break at the same pointing angle.
Hi Ray, lots of good advice here...
I found our car sweet spot for close hauled point of sail, but it took me some time to find it. Luff telltales at three different levels on our genoa, high, middle and low about ten inches back from the luff, helped me find it. Now when I begin to trim the sail, the first to stream is the low telltale, then middle, then high. At this point the sail is pretty flat with the draft forward. As I trim you can actually see the twist being reduced then eliminated. Terry
I found our car sweet spot for close hauled point of sail, but it took me some time to find it. Luff telltales at three different levels on our genoa, high, middle and low about ten inches back from the luff, helped me find it. Now when I begin to trim the sail, the first to stream is the low telltale, then middle, then high. At this point the sail is pretty flat with the draft forward. As I trim you can actually see the twist being reduced then eliminated. Terry
That's what I've always thought
however this article http://www.sailjazz.com/editorial/read/31 clearly implies that the telltales need to come alive (top bottom and middle) simultaneously for perfect car location. To each his own I guess..
however this article http://www.sailjazz.com/editorial/read/31 clearly implies that the telltales need to come alive (top bottom and middle) simultaneously for perfect car location. To each his own I guess..
Thanks for the car info
All: Thanks alot for placement of the jib car. Just to let you know, there was a sailing race today in the Great South Bay near the Robert Mosses Bridge. For fun, I ran along side some similar size cruising sailboats as mine and I pulled away from them. The 41DS with the vertical batten furling main works great. Nice day today with winds blowing from the Southeast at 13 knots. Didn't really know where the car should have been placed but having it 3/4 of the way back in the track worked fine. Will experiment on the car placement the next time I go out. Kind Regards, Ray "Second Wind"
All: Thanks alot for placement of the jib car. Just to let you know, there was a sailing race today in the Great South Bay near the Robert Mosses Bridge. For fun, I ran along side some similar size cruising sailboats as mine and I pulled away from them. The 41DS with the vertical batten furling main works great. Nice day today with winds blowing from the Southeast at 13 knots. Didn't really know where the car should have been placed but having it 3/4 of the way back in the track worked fine. Will experiment on the car placement the next time I go out. Kind Regards, Ray "Second Wind"
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