Pack type sailcover that doesn't act like a funnel

[DDW]

Another idea: a hybrid where the part up to the lazyjack battens is one part and a cover over the top is a removable part. Much smaller and lighter than the whole thing and you don't have to lift the sail to get it on. However hard to guarantee that it is peaked and sheds water.

That made me think of a refinement to the high-low batten idea. This looks asymmetric and a little funky, but also the fabric might easily sag between the two battens still making a trough. So in this version there is a high batten that has the flap. When the sail is about to get covered, you force the lazyjack lines together - the Doyle scheme works well for this - then fasten the flap over the low batten. The high batten guarantees the peak, forcing the lazyjacks together makes the section somewhat symmetric. The flap overlaps the low batten, can be fastened with bungie or ties so that no matter how the sail ended up and what the section looks like, it can be pulled tight enough not to have puddles. Would need slots for the lazyjacks on the low side. It would still look asymmetric while sailing, but of course only from directly in front or behind.

 

[DDW]

Probably talking to myself now, but here's a further refinement I'm leaning towards. Battens well down the side about half way, flap goes all the way to the other side overlapping the zipper, in the middle of it is a 1/4" batten. This is attached to a snap hooks, which are snapped around each pair of lazyjacks. These tend to ride up due to the lines pulling apart, especially with dyneema. So they will hold the small batten in a peak. It would be a very long flap and easy to lose under the sail, but I could keep the snap hook on the near side lazyjack which would prevent that to a great extent. I think I am going to sew up a section of this and see what it actually looks like in place.

 

[Gunny]

I’ve seen a few posts on a traditional cover with lazy jacks. I was planning to convert my traditional cover to a stack pack once new sail arrives but after reading this posting I’m going to keep my traditional sail cover. I sail and race a 46’ sailboat with 18’ foot and very large roach main sail. Jack lines attach to bottom of boom not the sail track as most stack packs attach. We losses the Jack lines once sail is stored and put the cover on, yes it’s a hassle, but sail never gets wet and is attached under the boom with twist clips so it can also breath. I suggest re-thinking your problem to determine if you could change Jack line attachment to under the boom and use a traditional cover. It will certainly be harder to install and remove but it will solve all your moisture issues. It also doesn’t effect the wind on the bottom of the sail while underway.

For those who don’t want to move lazy jacks the cover can be built or modified with some slits that accommodate the jacks then snap at the bottom. Works well on many boats like Alerions. The other item not discussed is mast attachment. Overall comment here is don’t skimp on batten hardware. While heavy bat car systems work well when installed properly and maintained.

 

[harryproa]

Keep the thoughts coming -

The solution we use on Harryproas is a wishbone boom attached to the mast ~where your gnav currently is and angled downwards to where the clew currently is. Install a line from the clew to the base of the mast as a vang, giving more purchase and a better load path (compression, not bending) than the gnav. The foot of the sail could also act as the vang, but it limits your setting options.

Make a bag that hangs under the boom. Zig zag a line from boom arm to boom arm under this bag. Tie the clew end off and attach the other end to the luff of the sail so the line is tightened and the bag lies within the arms of the wishbone when the sail is raised.

The top flaps on the bag are zippered together with an endless line through a pulley at each end. The sail, including the square head/big roach) sits below the flaps, so there is no zipper load. The boom slopes down so the water runs off it.

The boom rotates the mast so the sail is always hoisted and lowered pointing into the wind. No lazyjacks, flaking or touching the mainsail required. Release the main sheet, let the halyard go, tighten the main sheet, pull the zip string.

Reefing is similar. Release the sheet, the sail weathercocks. Drop the halyard to a preset mark, the bag under the boom is lowered along with the sail, lift the boom end up to the leech reef point and tighten the downhaul. Sheet on and go sailing. The dropped section of the sail is enclosed in the bag.

 

[DDW]

I am familiar with wishbones, having owned and sailed a few. It does make furling and covering the sail easy, however it also creates several problems, which my rig was meant to solve. Even now I equivocate a little, wondering if a wishbone might have been better. It was certainly considered in the design phase. The main problem is that the compression load in the bent wishbone arms would be very high on this sail, around 8000 pounds working. Not that bad for a straight column but challenging for a slender curved arm which will be loaded in bending. It might be substantially heavier than my boom, and higher up the rig. Then there are the problems of what holds it up? (topping lift is a PITA with square head), the reefed bunt problem (uncontrolled bunt when reefed), and some heavily loaded hardware well up on the mast. The reefed bunt problem is mitigated to some extent with a square head as the leach is much closer to vertical. How do you deal with the topping lift and a square head? One on each side and swap them like runners? In heavy air you might slack them but in lighter your are going to need it. Perhaps a fairly light (but very long) rigid vang running where the boom was?

 

[harryproa]

I am familiar with wishbones, having owned and sailed a few. It does make furling and covering the sail easy, however it also creates several problems, which my rig was meant to solve. Even now I equivocate a little, wondering if a wishbone might have been better. It was certainly considered in the design phase. The main problem is that the compression load in the bent wishbone arms would be very high on this sail, around 8000 pounds working. Not that bad for a straight column but challenging for a slender curved arm which will be loaded in bending.

If the load is that high, either bigger arms, more carbon or make them straight. Looks a bit different, but so does the gnav.

It might be substantially heavier than my boom, and higher up the rig.

I doubt it would be either, but interesting to compare them.

Then there are the problems of what holds it up? (topping lift is a PITA with square head),

The sail holds it up if there is enough breeze to need the vang. Otherwise the spare halyard can be used as the topper. If you do lots of sailing in light air and are worried enough about sail shape, a light topper on each side which were tacked may be less of a PITA than the gnav, lazy jacks, low boom and sail stowage/boom cover problems you currently have.

the reefed bunt problem (uncontrolled bunt when reefed),

It lives in the bag under the boom. As the sail is reefed, the bag falls and the bunt has nowhere else to go.

and some heavily loaded hardware well up on the mast.

There is no hardware (blocks, etc) on the Harryproa masts between the tack downhaul and the head apart from the auto halyard locks at each reef. I'm pretty sure the load where the boom attaches to the mast is less than that from a gnav holding down the boom from ~10-15% along it.

The reefed bunt problem is mitigated to some extent with a square head as the leach is much closer to vertical. How do you deal with the topping lift and a square head? One on each side and swap them like runners? In heavy air you might slack them but in lighter your are going to need it.

see above. At what wind strength does your gnav start to see an upward load? ie, when would you not need the toppers?

Perhaps a fairly light (but very long) rigid vang running where the boom was?

Could do, but tacking toppers in light air seems to me to be less hassle.

 

[DDW]

Straight wishbone arms would interfere badly with sail shape. Splaying them with a crossing piece in front doesn't really put the clearance where you want it. The gnavs are better in this respect as they are splayed widest at about the deepest draft point.

I did a quick calculation on weight and came up with about 160 lbs for a wishbone of sufficient strength, the boom weighs about 125. The 160 could be improved on by tapering size and wall thickness so it might get closer to 125. But there is no doubt that it is higher up the rig. The section required is about 150mm diameter and 6mm wall. The heavily loaded hardware up the mast is the joint between wishbone and mast. A similar joint exists on the gnav, but if it fails catastrophically you are handicapped, not crippled - you can still sail. If that joint goes on a wishbone you are crippled, so it has to be fail-safe.

You would need the topping lift anytime when the sail was down, when the sail was being raised or lowered, and probably when reefed. I have dealt with one on the wishbone rig I owned and there were many times I wished it gone - even without the square head. The boom is supported by the gnav in winds less that around 8-10 knots is my guess, with a rigid hydraulic vang it is a little hard to determine.

The reefed bunt problem is a real problem. As you reef deeper, the new reefed clew necessarily moves forward, and due to the slope of the wishbone also moves up. The foot of the sail stays were it was. By the 3rd reef on my boat, there would be >1m of sail hanging below the the reefed foot, representing about 70 sq ft. This isn't really under tension or well controlled, it is just lying there in the lazyjacks. Ordinarily not a problem, but in storm conditions it will fill with water, sagging between the lazyjacks. I have seen it happen, and exactly this phenomenon contributed to the abandonment of two boats with wishbone rigs in the North Atlantic. Perhaps some mitigating practice could be developed to deal with it, but it is really a Thing.

I could probably convert my rig to a wishbone. The gnav attachments are sufficiently strong and in about the right place for a wishbone joint. The gooseneck reinforcements are sufficient for a vang. One problem would be the sheeting, currently about 3/4 boom length and hard to move aft, must be boom end for wishbone. I consider it from time to time. Perhaps one of the biggest advantages of a wishbone is the furled sail is within easy reach.

 

[harryproa]

Straight wishbone arms would interfere badly with sail shape. Splaying them with a crossing piece in front doesn't really put the clearance where you want it. The gnavs are better in this respect as they are splayed widest at about the deepest draft point.

Splaying them works fine, if the splay is wide enough, made easier with a high aspect sail. Straights with a kink also works. The kink is highly loaded, but easier to reinforce than a curve

I did a quick calculation on weight and came up with about 160 lbs for a wishbone of sufficient strength, the boom weighs about 125. The 160 could be improved on by tapering size and wall thickness so it might get closer to 125. But there is no doubt that it is higher up the rig.

Do those weights (and heights) include the gnav?

The section required is about 150mm diameter and 6mm wall.

The C50 wishbone is 150 x 150 (6" x 6") square section with rounded edges as it is far easier to build than a bent tube. It's 4.6m (15') long. The arms weigh 72 kgs (158 lbs) in glass, 50 kgs (110lbs) in carbon/glass.

The heavily loaded hardware up the mast is the joint between wishbone and mast. A similar joint exists on the gnav, but if it fails catastrophically you are handicapped, not crippled - you can still sail. If that joint goes on a wishbone you are crippled, so it has to be fail-safe.

The loads on the join are easily calculated and allowed for. Adding extra carbon tow to the 150 wraps specc'ed to further strengthen it is low cost and easy. In the highly unlikely event the wishbone join failed, the front of the boom would fall to the deck, where it could be tied to the mast and sheeted as normal, but without the vang function. Not too different from the gnav failing, but without the hydraulic oil all over the deck.

You would need the topping lift anytime when the sail was down, when the sail was being raised or lowered, and probably when reefed. I have dealt with one on the wishbone rig I owned and there were many times I wished it gone - even without the square head.

One topping lift is a PITA, 2 is less work than any other set of strings on the boat. Link them if you want to get really lazy, connect them to the mast rotation if you don't want to have to touch them at all. Alternatively, it would be trivial to add a strut either side of the mast to the underside of the wishbone to support it. Similar to your long vang, but only necessary for a meter or so along the boom. The struts need to support the weight of the boom and sail plus maybe a couple of people hanging off it. Not huge. Make them pivot at the mast and you could adjust the boom height.

The reefed bunt problem is a real problem. As you reef deeper, the new reefed clew necessarily moves forward, and due to the slope of the wishbone also moves up. The foot of the sail stays were it was. By the 3rd reef on my boat, there would be >1m of sail hanging below the the reefed foot, representing about 70 sq ft. This isn't really under tension or well controlled, it is just lying there in the lazyjacks. Ordinarily not a problem, but in storm conditions it will fill with water, sagging between the lazyjacks. I have seen it happen, and exactly this phenomenon contributed to the abandonment of two boats with wishbone rigs in the North Atlantic. Perhaps some mitigating practice could be developed to deal with it, but it is really a Thing.

I don't doubt it is a Thing, but it needn't be. A solution is a rod (or lines) under the boom at the deep reef with the reefing line running around it. This would be put in place when the 2nd reef was in, or the sail was dropped (not a big deal on an unstayed mast) or could be pulled forward (or aft) via a line to the mast.

I could probably convert my rig to a wishbone. The gnav attachments are sufficiently strong and in about the right place for a wishbone joint. The gooseneck reinforcements are sufficient for a vang.

Moving the vang to the mast at deck level would increase the angle/reduce the loads and is the strongest part of the mast, so won't need beefing up.

One problem would be the sheeting, currently about 3/4 boom length and hard to move aft, must be boom end for wishbone.

I'd consider it every time the gnav leaked, lost pressure, required pumping, detaching, removing or maintaining. And when the the bunt of the sail flapped about with the third reef in. And each time I had to leave the cockpit to fight with the sail cover or got soaked as the sail was raised.

No reason why the sheet could not be along the wishbone. "Just" requires a heap more laminate/bigger section at the attachment. Or on a bridle between the boom ends, maybe integral with the vang.

I consider it from time to time. Perhaps one of the biggest advantages of a wishbone is the furled sail is within easy reach.

Perhaps, but for me, it is all about KISS: Maximising the time spent sailing and minimising the time and effort spent working. But then, I don't fret about varnishing the underside of the cap rail. Or anywhere else. Or even having a cap rail for that matter. ;-) Be boring if we were all the same!

 

[DDW]

Splaying them works fine, if the splay is wide enough, made easier with a high aspect sail. Straights with a kink also works. The kink is highly loaded, but easier to reinforce than a curve

I'd need to splay nearly 2m in a cross beam ahead of the mast to achieve sufficient sail clearance, it isn't a high aspect sail. That would at least look ungainly, and probably be ungainly. It isn't just the kink that is highly loaded. Each part of the arm is loaded in bending to the extent it is offset from CL. The kink is the most highly loaded, but either side of the kink is nearly the same load, diminishing linearly towards the ends.

Do those weights (and heights) include the gnav?

The C50 wishbone is 150 x 150 (6" x 6") square section with rounded edges as it is far easier to build than a bent tube. It's 4.6m (15') long. The arms weigh 72 kgs (158 lbs) in glass, 50 kgs (110lbs) in carbon/glass.

That's even a little heavier than I figured. It will be 27' on this boat, so close to 200 lbs. The gnavs are an additional 40 lbs or so, the heavy end with the hydraulics is at the boom, the rest is a carbon tube.

One topping lift is a PITA, 2 is less work than any other set of strings on the boat. Link them if you want to get really lazy, connect them to the mast rotation if you don't want to have to touch them at all. Alternatively, it would be trivial to add a strut either side of the mast to the underside of the wishbone to support it. Similar to your long vang, but only necessary for a meter or so along the boom. The struts need to support the weight of the boom and sail plus maybe a couple of people hanging off it. Not huge. Make them pivot at the mast and you could adjust the boom height.

I doubt two topping lifts would be less work that any other strings on the boat. When tacking, I literally don't touch anything at all except the autopilot tack button. Connecting them to mast rotation is an interesting idea, though there isn't a lot of rotation on a tack so it would get complex. I've thought of the short struts to support a wishbone. Any rigid support scheme needs to be easily adjustable as it will need to be adjusted every time the vang is touched. That is the beauty of nitrogen-over-oil hydraulics: the topping function is self tending.

Once you have both a boom and a rigid vang, the whole solution space is a similar continuum: my current implementation is a heavy boom with a lighter wishbone (or gnav if you prefer). You could have a heavy wishbone and light boom (or struts) acting as the vang. Connect them at the end or somewhere in the middle. All pretty similar really, only minor details separate them, and each has its compromises.

A variation is to make the whole deal rigid, either a cantilever boom or fixed struts, and adjust leach tension with a downhaul or moveable clew car. This is actually quite attractive, except that the adjustment means must be duplicated at each reef which discourages the idea. A vang does no more, but does it identically for each reef.

I don't doubt it is a Thing, but it needn't be. A solution is a rod (or lines) under the boom at the deep reef with the reefing line running around it. This would be put in place when the 2nd reef was in, or the sail was dropped (not a big deal on an unstayed mast) or could be pulled forward (or aft) via a line to the mast.

I don't see how this solves anything. If you actually go along and tie reef points like we used to do 50 years ago, you can tidy it up and keep it from filling, mostly, as it compacts the sail bunt. But a PITA, having to be done when you'd least like to do it. You might be able to have a brail line and pull from one end, but it would be a lot of string chafing in place all the time.

I'd consider it every time the gnav leaked, lost pressure, required pumping, detaching, removing or maintaining. And when the the bunt of the sail flapped about with the third reef in. And each time I had to leave the cockpit to fight with the sail cover or got soaked as the sail was raised.

No reason why the sheet could not be along the wishbone. "Just" requires a heap more laminate/bigger section at the attachment. Or on a bridle between the boom ends, maybe integral with the vang.

Perhaps, but for me, it is all about KISS: Maximising the time spent sailing and minimising the time and effort spent working. But then, I don't fret about varnishing the underside of the cap rail. Or anywhere else. Or even having a cap rail for that matter. ;-) Be boring if we were all the same!

I do think about it those times. I'm thinking about it now as the rod seals are weeping after the most recent rebuild a few months ago. The hydraulics are not an essential part of the gnav, the only other large boat I know of with a similar setup (the Open 60 Ocean Planet) had a cordage tackle doing the work).

The third reef bunt flapping isn't a problem with the current setup, sail is well controlled at all times. I only have to leave the cockpit at the end of the sail, to zip it up - and would have to with a wishbone as well. The wishbone solves the wet sail problem by the sail being well sloped when furled, the cover problems are somewhat the same beyond that. The situation with the cover would be greatly improved if only I had stuck to my insistence that the boom be raked. That would have had the twin benefits of drainage, and easier access to the sail.

Now I do not see how you do mid-boom sheeting with a wishbone. The sail foot is below it, so maybe close hauled you can make it work, but running deep it will not.

It was a moment of weakness that allowed me to be talked into the teak caprail. But quite difficult to replace now!

 

[harryproa]

You asked for suggestions, I supplied them. Your call whether you work out the details and test them or not or stick with what you describe as an imperfect system.

It's culturally interesting. In Aus if you suggest something new the first response is invariably no, followed by a bunch of increasingly inane reasons why not.
Here in Fiji, if you suggest something, the answer is Yes!, followed by solutions to problems as they arise.

Not everything works out, but it is a whole lot more fun thinking of and trying new ideas here.

 

[DDW]

To be completely accurate, I asked for suggestions on a sailcover, not a new rig. If the rig is built around covering the sail, then in-mast furling probably wins.

The very nature of boat design is picking between two or more imperfect systems. I've owned wishbone boats, not against them or the idea. But I am acutely aware of their inherent imperfections - and there are some - which is why it was rejected in the design process.

 

[willsailforfood]

I had Doyle Stack Packs on the main and mizzen, I've gone back to traditional sail covers, no regrets there. For all the added hassle and windage, I just didn't see much advantage to them. The whole arrangement is far simpler now.

I kept the lazy jacks, and decommission the boat each winter and store the sails on land when the rainy season arrives. Bonus is I can see all the attachment points clearly and anything that needs attention is clearly visible. The Stack Packs hid a lot from view.

 

[slug zitski]

My 2 cents: move zipper all the way to one side, higher up. Have a doubler layer of something waterproof added to under side of flap. Set up sail/boom so trough can drain

They alway soak the sail…water flows in from the luff or clew or zipper sun cover

stack packs are not sail covers

drop the stack pack , then fit a proper sail cover

recently I was asked to strip the main off a boat so that the riggers could work on its boom

the boat had a stackpack with a center zipper cover and had been sitting at the dock for a month or two

when it removed the stackpack the mainsail was a science project of mold and fungus…even had little green plant shoots popping up

 

[DDW]

drop the stack pack , then fit a proper sail cover

Fine on a small sail. Impossible as a practical matter on a large sail, unless you have a crew of 5 and some scaffolding for them to work on.

 

[SASSAFRASS]

If you are in the PNW and see it go look at the settup Karl did on Ocean watch, big expedition sloop. It looks like to takes a little more finesse to manage, but it's very compact and uses inverted curve and lazy jack arrangement to be able to not have the normal square box. I'm guessing things stay pretty dry.

 

[DDW]

Not up there now, can't find any pictures online. I've come up with a plan for what I want to do, now have to execute. One variable is the new Hydranet sail is pretty stiff so it takes more room than the old string sail, I'm told it will get softer with use so I'm sure just how tight to make the cover. It barely fits in the old one, starting the tear the rotten stitching, so I guess that is minimum size.

 

[SASSAFRASS]

Greg at Oyster creek canvas in Bellingham built it if you want to dig in deeper.

 

[DDW]

I've settled on a design that will have a peaked top with a zip on both sides. I'd expect to usually use the zip on one side, but both sides allows the peaked top to be removed entirely, or replaced when I work on Rev 2 :-(.

That opens the possibility of using Seamark waterproof Sunbrella for the top only. Does anyone have experience with the durability of the coating? There have been some uncertain opinions in prior threads than maybe the Seamark is less flexible/more bulky than the standard? Will I just end up with a pile of mildew?

While we are at it, I intend to sew a strip of phifertex into the bottom for drainage and ventilation, but I've never worked with phifertex. Is it strong and durable enough to replace the Sunbrella in a continuous strip, or should it just be some inlaid panels.

 

[taliessin]

We have a stack pack with a piece of fabric which goes around the mast and zips to the bow end of pack on both sides. The main is loose footed. No issues with water.

 

[willsailforfood]

We have a stack pack with a piece of fabric which goes around the mast and zips to the bow end of pack on both sides. The main is loose footed. No issues with water.

We had the same, and still went back to traditional sail covers. The pack always kept things I felt should be regularly inspected out of eye's view, and I never found the stack pack added any real convenience. You still have to manage the flake (even with lazy jacks), and pulling a zipper vs snapping a few clips saves almost no time or convenience in the real world.

They seem like a solution looking for a problem.