Pack type sailcover that doesn't act like a funnel

[DDW]

I have a Doyle Stackpack on the old sail. It's design acts as a funnel, directing water into the folds of the sail. Combine that with a laminate sail, I get about 20 gallons in there, in a month or two it has its own ecosystem of flora and fauna. I'm done with laminate sails, too many broken promises over too many decades about how the mildew and delamination problems have been solved. New sail coming, Hydranet, which has the opportunity to dry if it is only given a chance.

So I'm trying to come up with a pack construction that will keep all or most of the water out from the top, and some ventilation and drainage on the bottom. The latter seems straightforward, mesh on the bottom. However the zipper top is complicated. Doyle puts battens near the top, there are wings of cloth that extend up a couple of inches, webbing is sewn from the batten up through these for the jacks. The zipper flaps inevitably form a trough and collect all the water they can and direct it into the sail.

An obvious improvement is to place the battens and webbing so there are no trough walls like the Doyle. But to really shed water, the zipper must form a peak, or maybe a peak with the zipper to one side on the downslope. I haven't figured out how to do this. The cover I have was modified once, then a new one built each time making the circumference smaller, but making it so small that the sail itself provides the bulk to make the peak doesn't seem possible, and still get it closed easily. If the webbing terminating the jacks is sewn right up to the zipper, it would make the zipper peak - but would be very hard to get closed, and probably ruin the zipper in short order.

Blue is cover, red is jacks. A perfect water trough:

 

[Zonker]

Do think about how your zipper is protected from UV. Our UK cover had an EXTRA chunky zipper which was very robust and made closing a cinch. Just tug and the zipper didn't care if the cover was stretched open. The zipper was covered by fabric seams along the length EXCEPT at the very aft end where it was exposed - and it sun rotted there.

You're not going to make it totally waterproof so accept the fact that this style will funnel more water inside and just let it ventilate.

Or buy the a very long waterproof zipper. They do exist but are a pain to open and close if you can't get access to the very end of the boom

 

[penumbra]

Ours slopes fore to aft. While a significant amount of water gets in the sail, it's not as bad as the rectangular ones. I've still considered in the next one having the zipper off center to help.

If you're getting a new sail and a new cover anyway, the better solution is a Dutchman system. Easier to handle the main and no rain in the cover.

 

[IStream]

I'm with penumbra. My cover has a significant slope fore-aft and that seems to be very effective at shedding the water before it has a chance to seep through the zipper. After a full PNW winter, I seldom have more than a cup or two of water nestled in the folds of my (Dacron) sail.

 

[DDW]

The existing cover has the largest zipper YKK makes I think a #15. The size of the sail may be relevant: 90 m^2 and weighing around 200 lbs with the battens. It has generous flaps over the zipper which still seems in good shape. I accept that the cover cannot be made watertight, nor is that necessary since often the sail will be put away wet. With the laminate sail, it would accumulate water with each rain, none would drain or evaporate so it just turns into a perfect catchment. I'm hoping that the Hydranet will not let this happen. I keep the boat in a relatively dry climate, but if water goes in and none ever comes out, it is a problem.

I can lift the boom a little which helps to drain, but not enough. Dutchman isn't an option on a squarehead or a bendy rig.

I'm noodling on ideas like this. Move the big battens down to the sides. This leaves much longer flaps that have to go over the top. They have a tendency to get trapped under the sail when it is dropped. So right next to the zipper would be a light batten, and some secondary "flap jacks" to hold them up, both during the drop and when zipped. Since the sail weight is carried by the larger ones, I think it would be relatively easy to close. When unzipped, they would hinge to the side, hanging by the flap jacks. I currently do not have cockpit adjustable lazyjacks as the unique Doyle scheme does not require them, but might have to add them to make this cover behave when the sail is set.

 

[DDW]

I'm with penumbra. My cover has a significant slope fore-aft and that seems to be very effective at shedding the water before it has a chance to seep through the zipper. After a full PNW winter, I seldom have more than a cup or two of water nestled in the folds of my (Dacron) sail.

The problem with the fore-aft slope is it has to be greater than the stack height of at least the lower batten cars. I'd have to get the boom maybe 4 - 5 feet high a the sail clew. As high as the vang will get it, we still soaked the sailmaker when the sail was removed from the cars.

I'd think a Dacron sail would leak any significant pond through. I'm hoping for the same from Hydranet. The laminate would hold it forever.

 

[IStream]

Ah, possible slight misunderstanding. I was talking about the slope of the zipper itself, not the boom. On mine, with the boom horizontal, the zipper is 3-4 feet higher than the gooseneck in order to enclose the height of the car stack but at the back of the boom, the cover is less than a foot off the boom. As a result, there's about a 1:7 slope along the length of the zipper and the majority of the water that hits the zipper runs towards the aft end of the boom.

 

[DDW]

That might be easier, though I can only drop the boom a bit before it hits the dodger. On thing the Doyle pack has it "stays" or vertical battens at the aft end, making it stand up about a foot. Every time it went back to them I took them out, and every time is came back with new ones. In any case there is a low spot in the water trough about 1/3 of the E.

 

[IStream]

Hmm. How about installing some small stainless grommets at the base of the "wings", at least where the low spot is, so there's a way for the water to drain off to the sides?

 

[DDW]

Problem is it sags towards the zipper in the middle. The "wings" only aggravate. But there needs to be a way to get the center to be the highest local point, not the lowest. You don't build a house with a valley in the middle of the roof, you put the peak there.

Actually I hope the main problem is the zero permeability membrane sail - which will get fixed. I never had this problem with a woven dacron sail. In the wet PNW maybe still a problem but in SF if it can drain in say a day it will be dry most of the time. It hasn't rained here since January, none. Yet when we removed the sail in May, a good 20 gallons drained out. It stays there, literally, forever.

 

[Zonker]

We had a Hydranet furling genoa. Lots of rain in the tropics and no (significant) mildew growth

 

[Mitre cut]

I ease off the lazy jacks on one side so the top of the cover is not level.

 

[Max Rockatansky]

Just set the jacks so that one side is higher than the other. Edit: Sorry I just saw MitreCut’s post

btw, Hydranet does trap water. It’s fun to raise the sail and get a shower at the same time. (I have not bothered to take the above advice.) But that said the sail has not mildewed

 

[steele]

I suspect the reason stackpacks don't already have the modifications you are considering is they add bulk and weight resuling in poor performance while sailiing the boat. The extra cloth, battens, and line will have to be wrangled and secured under sail. An asymmetrical set up could result in lots of bulk and flogging on one side of the boom. You are a pretty cutting edge sailor so if you find something that works please share.

At the risk of stating the obvious, have you considered a standard sail cover? Mine is secured along the mast with velcro and a heavy duty zipper, and under the boom with large fastex buckles. It is much quicker to use than those old metal snaps. The open area under the boom is fairly wide allowing for great ventilation along it's whole length. A change I would make is to use lighter weight fabric sacrificing some durability to make it easier to deploy and stow. Lazy jacks can be left in place with slots sewn in the cover, or brought back to the mast. I have had both and prefer to stow the jacks at the mast before adding the cover, especially with dynema lines which are very easy to handle.

 

[DDW]

We had a Hydranet furling genoa. Lots of rain in the tropics and no (significant) mildew growth

Good to know. Of course a furling jib will drain. The other thing about Hydranet is I assume it can be cleaned of mildew if needed, the laminate sail could not be.

I ease off the lazy jacks on one side so the top of the cover is not level.

I do not have (easily) adjustable lazyjacks - however if that is the solution, why not build the cover that way? Putting the zipper to one side and eliminating the water trapping wings I'm sure would have gone a long way to solving this problem. My aesthetic sense is violated a little by the non-symmetry of it but violated much more by an ugly mildewed sail.

btw, Hydranet does trap water. It’s fun to raise the sail and get a shower at the same time. (I have not bothered to take the above advice.) But that said the sail has not mildewed

Was that water trappage long term? I took a piece of Hydranet and put some water in it, didn't drain like mesh but it seemed like the water slowly seeped through - similar to new heavy dacron. Sf Bay has two seasons, dry and warm and wet and cool. The dry and warm are the conditions for mildew, if the sail stays wet.

At the risk of stating the obvious, have you considered a standard sail cover?

I have considered this at least in passing. I've grown lazy using the stackpack, and a separate cover becomes more onerous as the sail gets bigger - how big is your sail? The last separate cover I had was on a 600 sq ft main, not too bad to unroll and get around and under the sail - but that sail was also only about 65 lbs and at waist level. This one is 200 lbs and at eye level. Pretty sure it will be a PITA, but it hasn't been proven.

The real Doyle Stackpack has a feature the others lack, that being a membrane which holds the cover tight and against the sail once hoisted. That is much tidier than the usual one blown open at the bottom (unless furled). I don't think I will attempt duplicate this in the new one as it has other problems, but figuring out how to tidy up the pack once the sail is set is another challenge I am trying to solve.

A more radical departure would be to add racks to the boom to terminate the lazyjacks, opening up other possibilities for the cover. It would be major work and I don't think I want to take it on this time around without compelling reasons.

 

[steele]

Your main is much larger than mine. You could probably make a traditional cover work with lightweight fabric and a step on the mast, but going to an integrated cover makes more sense.

 

[eliboat]

Am I missing something… couldn’t a flap with velcro on one side (or some other means of attachment be sewn on one side of the zipper. After the sail has been lowered into the pack the flap would be flipped over the top of the zipper, thus keeping the rain out. Is this not possible? I’m interested to know, as I am considering a stack pack style cover this season, and I really don’t like the idea of rainwater getting trapped in there

 

[Max Rockatansky]

The problems with the big flap are that it’s big and difficult to reach, and also it will need to be fastened down in some way (see ‘difficult to reach’ above). Also, the flap won’t play well with the zipper

Another simple solution is to rise or lower your boom such that water will tend to flow out an end

 

[DDW]

A flap covering the trough will not do it. Water is extremely dependable in its tendency to run downhill. Sunbrella is not waterproof when new, and certainly not a couple of years on. The pool of water will soak through the flap onto the sail. It will not soak through the laminate sail, even given years.

Sloping the boom sufficiently would do it - but not possible on my boat. It has to have a fair slope sufficient to shed before it soaks through. The slope is limited by vang travel and don't get me started on the vang!

 

[longy]

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