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Traveler for mizzen? (CS-17)


MisterMoon

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Has anyone ever tried a traveler on the mizzen sheet on a CS-17 that would allow sheeting closer to centerline without over tightening the luff and possibly give a few more degrees point when going upwind. 

Note my mizzen sheet is not to plan. It runs as follows: The sheet is tied off to a becket block on the end of the sprit boom. It goes down to a block on a rope horse, centered right above the tiller. From there it goes back up to the becket block on the boom end, up the boom to a turning block at the mast and down the mast to a turning block and cam cleat on the thwart. 

 

I find I can nearly sheet the mizzen on center with this set up, but the leech is so tight the boat will not sail to windward very well at all. Going hard to windward, the end of the mizzen boom is usually just inside the corner of the transom.

My hope in making a rope traveler across the transom would be to allow the boom to be closer to centerline without completely closing the top of the mizzen and make it gain a few more degrees to windward. Based on GPS tracks, I normally tack through about 105 degrees. Just picking up 3-4 degrees with no loss in speed would be huge. 

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Has anyone ever tried a traveler on the mizzen sheet on a CS-17 that would allow sheeting closer to centerline without over tightening the luff and possibly give a few more degrees point when going upwind. 

Note my mizzen sheet is not to plan. It runs as follows: The sheet is tied off to a becket block on the end of the sprit boom. It goes down to a block on a rope horse, centered right above the tiller. From there it goes back up to the becket block on the boom end, up the boom to a turning block at the mast and down the mast to a turning block and cam cleat on the thwart. 

 

I rigged my Lapwing the same way and I find I can sheet  in too far without over-flattening the sail.  I find sheeting inside the quarter too close.  A traveler would add a little more control to the over sail shape, but I don't see it making the boat more weatherly.  I haven't really tried to measure the angle I can tack through, but don't see less than 100 happening.  In a blow, the line horse, by pulling down to leeward can help flatten the mizzen, but need not in lighter airs.

 

On a related note: how would you rig a traveler to not interfere with the tiller?

 

edit:  Where exactly do your horse ends secure to the transom cap?  The location affects sheeting angles and might be part of your sheeting issues.

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This whole discussion comes from sailing on sloop rigged OPBs. On a cat ketch, I'm visualizing the mizzen as the main on a sloop and the main as the genoa. But that may not be a valid comparison...  Pulling the boom to centerline on many sloops while not over tensioning the sheet really adds to the pointing ability. Barber haulers on the jib help a lot as well. 


It would be a rope traveler over the top of the tiller. I'd put fairleads on the corners of the transom leading to cam cleats on the inside coaming. 
 

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When Graham was in PT a couple of years ago, I asked him if a traveler on the miz would help with pointing; his answer: "Probably"  Three or four degrees is well worth some trouble to achieve if you seriously want to get the boat up the hill.

 

Your sheet arrangement makes sense; and with the rope horse you're halfway there for an adjustable sheet lead. I sail on an OPB too, a fractional sloop, and we've found that the leech of the main is as important a focus for good trim as anything else in the rig. A cat ketch mizzen would likely be less critical, but it would be nice to know where that sweet spot of trim is.

 

I for one would love to hear the results of your tests, when you get it figured out for all the rest of us. :-)

 

btw, how open do you trim the main for upwind?

 

cheers,

Lynn

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The mizzen works mostly in the shadow of the main upwind, so hauling in it tighter might get a touch more windward ability, but not as much as you'd think, before you're just pinching down. A barber hauler might be the easy approach, which could be as simple as a line dangling from the sprit you can use to to haul it mostly horizontally, but the lower 2/3's of the sail will still be stalled if too tight. Sloops have the same problem if the main is too tight. Only two good solutions, neither of which are easy. The first is to get more distance between the main and the mizzen and the second is to cant the mizzen to weather.

 

I've experimented with canting the mizzen and it works very well. If the thwart (for example) is used as the pivot and a track and shoe used on the mizzen heel, some arrangement can be made to get the mizzen to cock to weather. I've done this on a conventional ketch with a free standing mizzen and I've used a length of all-thread  and a cordless drill. I can cant about 15 degrees to weather in a few seconds. The heel of the mast sits in a HDPE track, that matches the arch from the pivot, which is considerably higher than the CS series thwart (it's a bigger boat) and a coupler rides on a sleeve attached to the mast's heel. The all-thread runs through the coupler and I have a double nut arrangement on one end, with an old 12 VDC cordless drill fixed. The hard part is remembering if to use reverse or forward to get the mast to go the way you want. I sail with a buddy's Santania 20 regularly and I can hang with him upwind, when previously I couldn't dream of it. He has maybe a degree or two more ability, but he's getting into a pinch situation trying to out do me. Previous to the canting mast, he crushed up uphill be several degrees. Underway, the mizzen upper 2/3's is drawing, though the lower 1/3 still shows some signs of backwind, if sheeted tight. The result is the mizzen is offering effective area upwind, driving the stern to leeward.

 

On a CS (or similar) boat, I can't see how this could be easily accomplished, with the case in the way, unless the mizzen was offset a few inches. With some quick math a 2.5" diameter mast, with a 16" purchase (thwart) would need to be 5 3/8" away from the case to cant 15 degrees (centerline of mast to case side at the heel). It wouldn't be a big job to drill a new hole in the thwart and slide the mizzen over 6". This isn't enough to hurt anything and you'd be able to hang with sloops uphill. It has an added side benefit, which is the staysail has a much better  angle, with the mizzen canted, so you can carry it longer and higher. It looks a little weird, which is what my buddy says, but once you get use to it . . .

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There may be a tendency to look at the mainsail/mizzen interaction like the jib/mainsail interaction on a sloop.  This would be a mistake for several reasons.  A jib overlaps the mainsail but is not located directly in front of it and much of the main is away from the influence of the jib.  The main chord must be trimmed at a closer angle than the jib chord or it will be seriously backwinded and stall the boat. The mizzen is much smaller and is located where it is completely in the disturbed air coming off the mainsail when sailing closehauled.  On a ketch, the main is the driving sail and a mizzen is trimmed so it will have minimal backwind and hopefully provide some windward lift.  On a CS the mizzen is large enough in comparison to the main that it will provide some drive.  I have not found that trimming either sail well inboard is an advantage in VMG and a center mounted mizzen sheet does as well as anything that will lead it more to windward.  I have settled on a short rope traveler over the tiller with a sheet attached to a block sliding on the traveler.  I'm not certain this is perfect but don't think it can be improved very much.  I very much doubt that "three or four degrees" more to windward is remotely possible as that is a huge change on a race course.

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Tom, with your "...short rope traveler over the tiller with a sheet attached to a block sliding on the traveler.", do you still run your sheet forward along the sprit?

 

Do you think that a bimini top could still be used, or will the sheet interfere with it?

 

Chick,

 

The drawing shows how I rig the mizzen sheet and yes, I much prefer having main and mizzen sheets at the mizzen mast on the thwart.  I guess the sheet is as clear of obstructions as it can be made but whether there is room for a bimini, I don't know.  Never considered a bimini over the aft cockpit before.  Are you considering a bimini to be used while sailing your Mark3? 

 

The traveler is only long enough to give adequate clearance for the tiller operation and installing it and taking it off.

post-162-0-52481900-1452613053_thumb.jpeg

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Tom, yes to the Bimini. With my sun-damaged Florida skin, and history of melanoma, I do want a Bimini. Trouble is, a stock Bimini is too long to fit between my boom gallow and mizzen mast, so it will have to be custom. Maybe the aft end supported on the gallow. Ant thoughts on this?

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Tom, yes to the Bimini. With my sun-damaged Florida skin, and history of melanoma, I do want a Bimini. Trouble is, a stock Bimini is too long to fit between my boom gallow and mizzen mast, so it will have to be custom. Maybe the aft end supported on the gallow. Ant thoughts on this?

 

Chick,

 

You had a gallow on your Mark2 didn't you?  I'm sure you can devise a system that will work.  Making the sprit a bit longer might make it easier to fit things aft.

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Ahhhh, now I see what you mean. The sprit isn't the problem. My boom gallow (gallows?), which also serves as "mast-carrier-when-trailering" is the aft limitation. I have the gallows mounted as far aft on/in the coaming as possible. Other than having to make a custom Bimini, I don't think it's a big deal.

 

This is the gallows on my last boat, CS-20 Mk-2. (The original Summer Breeze)

post-1823-0-81287800-1452632497_thumb.jpg

 

This is the tube through the coaming to holdthe legs of my gallows on this boat.  (The new Summer Breeze)

post-1823-0-70321900-1452632543_thumb.jpg post-1823-0-21571300-1452632545_thumb.jpg

 

I braved the cold and did some sanding today. Snow forecast for this afternoon.

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  • 2 weeks later...

Mine will be a little different, Chick.  Roughly the same idea, but with a few changes.  First of all, I will not have a block running on a bridle attached to the transom.  I will have a bridle with a fixed loop on the centerline of the boat.  The block will be attached to the fixed loop.  It will not, therefore, be allowed to move off the centerline of the boat.  Secondly, the PVC guide you have mid-sprit is prone to break and chafe your sheet.  I will use a nylon ring, attached to the sprit by an eyestrap.  (See photo-- sorry, it wouldn't crop for me.)  At the mast, I'll also attach the block to the sprit, not the mast.  I want the masts to be as clean as possible, for some reason.  The sprit is held in place by the snotter, so I don't forsee (famous last words) a problem with doing this.  I "hope" to be able to supply you with photos of this set-up soon, but you know how that is.  I'll be happy to come up and show you all of this, when I deliver your chunk of leather.

post-3770-0-38152800-1453343623_thumb.png

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Mine will be a little different, Chick.  Roughly the same idea, but with a few changes.  First of all, I will not have a block running on a bridle attached to the transom.  I will have a bridle with a fixed loop on the centerline of the boat.  The block will be attached to the fixed loop.  It will not, therefore, be allowed to move off the centerline of the boat.  Secondly, the PVC guide you have mid-sprit is prone to break and chafe your sheet.  I will use a nylon ring, attached to the sprit by an eyestrap.  (See photo-- sorry, it wouldn't crop for me.)  At the mast, I'll also attach the block to the sprit, not the mast.  I want the masts to be as clean as possible, for some reason.  The sprit is held in place by the snotter, so I don't forsee (famous last words) a problem with doing this.  I "hope" to be able to supply you with photos of this set-up soon, but you know how that is.  I'll be happy to come up and show you all of this, when I deliver your chunk of leather.

 

The attachment to the short traveler (more like a bridle really) does not move much off center in use, so it might as well be fixed in place.  Your comment on the PVC guide is very wrong.  The guide was made from a pipe section that was heat formed to eliminate any possible chafe, minimizes friction and does not bind like a thin ring would be more apt to do.  I think attaching the inside block to the sprit could also be a mistake.  If it is on the sprit, sheet tension will pull down and aft on the sprit and can distort the sail.  It will also fight with the snotter tension and flatten the sail more that you might like in light wind or downwind.  May not be big deal but attaching the sheet block to the mast works quite well and places no load on the sprit. These are the famous last words I see and, as always, the devil is in the details. 

 

Experimentation is always the best answer to these kinds of ruminations so try your method and let us know how it works out.  That is the way I learned most of what I think I know.  What I think I know is open to modification.

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Oops.  Sorry, MisterMoon, I wasn't paying attention, and thought that Chick originated this thread.  Let me attach a sketch.  

 My mizzen is rigged exactly the same as Thrillsbe's sketch except I don't have anything catching the sheet in the middle of the sprit. It's never really a problem anyway. Also, in practice there isn't all that much tension pulling down on the block on the sprit. I could move it to the mast but that makes rigging at the ramp a little slower, so I leave it where it is. 

 

I would not change the double ended mainsheets, however. 

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After reading this thread, I can only offer that VMG is what you care about when going upwind. On two separate boats I've used the VMG function on my GPS to figure out whether pointing high (yes for my old sloop rigged O'day daysailer) was my best route to weather, or bearing off a few degrees (definately in my Cat-ketch rigged Sea Pearl). This requires a bit of planning, but since you are in essence just reading the VMG number you can fool around and get results in a variety of conditions. For example, I've figured out on the SP that adding the water ballast in waves over 2' gets me to weather better as the boat punches through waves better. I am sure the hull shape of the CS boats changes the game, but I plan on doing the same thing when I get my boat built.

 

FWIW on my SP pulling the mizzen boom to the center-line actually seems to worsen it's VMG. Unfortunately the stern is so narrow and the boom so high that it's hard not to be pulling hard down on the boom to get it to center. I'd bet that isn't as much a problem on a wider boat like the CS boats.

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