I have an O'Day 25 which I am going to replace a fixed block with an adjustable track. I have a 135 furling Genoa to be installed at the same time, and the clew I expect will be 12-18 inches off the deck (I am installing a CDI FF4 furler). My question is, how do I determine where to put the track? How far toward the cabin, or out toward the rail? I have read some people place them on top of the cabin rather than on deck - what (if any) advantages are there to moving closer to the mast? How long should the track be? The boat has existing tracks / cars on either side of the cockpit on the outside of the boat under the lifelines. I think I could tell if the sheets are pulling at the correct angle once in place, but I don't know where to start from as far as placement. Any and all advice is appreciated.
What is the correct position of jib tracks
- Thread starter muised
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Jib - Genoa Cars
Muised, Hey now, slow down thar hoss, do not install, drill holes, of get yer sawsall out yet. Before doing this and if intent on the roller-furling, then go on ahead and install the furler.Then go sailing and SEE what your sail is doing and why. Math can do it but factors on paper do not allways work, so take her out, and take notes. The inside, cabin-top car-rails are likely for a tighter close hauled tack. Hey has any of you mates heard anything from sailortonybob and his Gulf passage? BTW the word is, nth as in 'the nth degree' math and physics...;-)
Muised, Hey now, slow down thar hoss, do not install, drill holes, of get yer sawsall out yet. Before doing this and if intent on the roller-furling, then go on ahead and install the furler.Then go sailing and SEE what your sail is doing and why. Math can do it but factors on paper do not allways work, so take her out, and take notes. The inside, cabin-top car-rails are likely for a tighter close hauled tack. Hey has any of you mates heard anything from sailortonybob and his Gulf passage? BTW the word is, nth as in 'the nth degree' math and physics...;-)
Great Tool
Cars on T track are great tools for different conditions. They offer changes in control over leech tension and sail shape. I use ours most often to induce twist when the wind picks up to help stabilize the boat. Or as we reach (or in real light air), I'll move them forward to get more pressure down than back. Pick up a trim book for details, it's hard to describe here. If you cruise, get cars with pins in them to stop in the track- no need for towable cars on a cruiser. I wouldn't install them on the coachtop, that's for way upwind with a small headsail or for a staysail... I'm sure lots of good responses here to follow: B
Cars on T track are great tools for different conditions. They offer changes in control over leech tension and sail shape. I use ours most often to induce twist when the wind picks up to help stabilize the boat. Or as we reach (or in real light air), I'll move them forward to get more pressure down than back. Pick up a trim book for details, it's hard to describe here. If you cruise, get cars with pins in them to stop in the track- no need for towable cars on a cruiser. I wouldn't install them on the coachtop, that's for way upwind with a small headsail or for a staysail... I'm sure lots of good responses here to follow: B
Make sure...
You want a fair run from the block to the winch no matter where it is on the track. That generally means you want the sheet running outside the lifelines to the block, then under them to the winch. You want the aft-most block position on the track to be where you will sheet the sail flattest on its foot, and you want to take into consideration that someday you might purchase a 150, and then will need more room aft to slide the block farther back. The fixed block you have now is most likely a compromise, but the farther forward you can run your new track, the more versatility you have in using it for smaller headsails as well. In my view it is better to have some track you end up not using than to wish you had another foot or more. Be sure to look at other boats like yours or talk to owners to see what they did and how they like it.
You want a fair run from the block to the winch no matter where it is on the track. That generally means you want the sheet running outside the lifelines to the block, then under them to the winch. You want the aft-most block position on the track to be where you will sheet the sail flattest on its foot, and you want to take into consideration that someday you might purchase a 150, and then will need more room aft to slide the block farther back. The fixed block you have now is most likely a compromise, but the farther forward you can run your new track, the more versatility you have in using it for smaller headsails as well. In my view it is better to have some track you end up not using than to wish you had another foot or more. Be sure to look at other boats like yours or talk to owners to see what they did and how they like it.
- Jan 22, 2008
- 519
jib lead angle
It depends on the sail, but the AVERAGE position for a particular sail is an imaginary line that follows the miter seam through the clew of the sail then continues back to intersect the deck. This point moves forward to tighten the leech and back to tighten the foot, essentially controlling the slot. The next larger sail using the same measure will intersect the deck at a different place. Once all of these points are marked on your deck you have your furthest forward and furthest aft position for a jib track. The next measure is somewhat more controversial. Each average point should be on an 18 degree vector from the tack of the sail to the centerline. Place a dot wherever a mark intersects the 18 degree vector. Join your dots along the vector line and that determines the length and angle of your jib track. Your working sheet may only have so much effect in pulling your clew towards the desired position on the track. You may have to use the lazy sheet to close the slot furhter, otherwise use a barber hauler.
It depends on the sail, but the AVERAGE position for a particular sail is an imaginary line that follows the miter seam through the clew of the sail then continues back to intersect the deck. This point moves forward to tighten the leech and back to tighten the foot, essentially controlling the slot. The next larger sail using the same measure will intersect the deck at a different place. Once all of these points are marked on your deck you have your furthest forward and furthest aft position for a jib track. The next measure is somewhat more controversial. Each average point should be on an 18 degree vector from the tack of the sail to the centerline. Place a dot wherever a mark intersects the 18 degree vector. Join your dots along the vector line and that determines the length and angle of your jib track. Your working sheet may only have so much effect in pulling your clew towards the desired position on the track. You may have to use the lazy sheet to close the slot furhter, otherwise use a barber hauler.
hmmmm, vectors....
Personally, I'm not that spectacular with serious math-- but if you can draw it out, that would be interesting to see. I'll stick with the simple method- adjust cars till all 3 sets of inside telltales luff together, then adjust from there. Still, if you could post a diagram of the vector thingy- that might be interesting to look at. B Bob- the only sheets on my boat that go under lifelines are spinsheets, do you use toe-rail track? Inquiring minds and all that
Personally, I'm not that spectacular with serious math-- but if you can draw it out, that would be interesting to see. I'll stick with the simple method- adjust cars till all 3 sets of inside telltales luff together, then adjust from there. Still, if you could post a diagram of the vector thingy- that might be interesting to look at. B Bob- the only sheets on my boat that go under lifelines are spinsheets, do you use toe-rail track? Inquiring minds and all that
jib track position
here's a picture. I think 18 degrees is a bit wide, but hey, I have a Catalina so what would I know about an O'Day? On my C27 the angle to the toe rail is about 14 degrees. My inside track is around 10. If I were you I wouldn't worry about it. Locate the track according to the picture then you can put a block on the toe rail for reaching if you feel the need. Hmmm... I'm try to post the picture but it ain't happening... Phil????? Okay, I'll post the link to the pic on the O'Day website, http://websailor.home.att.net/pics/pic0010_oday25_kruso.jpg
here's a picture. I think 18 degrees is a bit wide, but hey, I have a Catalina so what would I know about an O'Day? On my C27 the angle to the toe rail is about 14 degrees. My inside track is around 10. If I were you I wouldn't worry about it. Locate the track according to the picture then you can put a block on the toe rail for reaching if you feel the need. Hmmm... I'm try to post the picture but it ain't happening... Phil????? Okay, I'll post the link to the pic on the O'Day website, http://websailor.home.att.net/pics/pic0010_oday25_kruso.jpg
Genoa Track Locations
I have a book on boat design and equipment layout called "Designed to Win" by Roger MArshall. They indicate an angle with the boat centerline of from 7.5 degrees to 10 degrees with two or three tracks to accomodate sails from #1, #2 Genoas at 7.5 degrees to the #3 and #4 on the 10 degree line. If one track is used and is parallel to the boats centerline, the car position for the #1 would be aproximately where the 7.4 degree line crosses the traek while a more forward car position would be a 10 degree angle for the #4 jib. The examples were IOR racers from 1979. I'd imagine a cruising boat might not sheet in as tight but 18 degrees sounds like it is way too wide. Take a look at some race rigged boats of your size with the same mast head rig.
I have a book on boat design and equipment layout called "Designed to Win" by Roger MArshall. They indicate an angle with the boat centerline of from 7.5 degrees to 10 degrees with two or three tracks to accomodate sails from #1, #2 Genoas at 7.5 degrees to the #3 and #4 on the 10 degree line. If one track is used and is parallel to the boats centerline, the car position for the #1 would be aproximately where the 7.4 degree line crosses the traek while a more forward car position would be a 10 degree angle for the #4 jib. The examples were IOR racers from 1979. I'd imagine a cruising boat might not sheet in as tight but 18 degrees sounds like it is way too wide. Take a look at some race rigged boats of your size with the same mast head rig.
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