Sail Stackpack /Lazy Bag design

[StefanSG]

Hi
I would like to make a stackpack sail bag for my 9'8" boom I've looked at Sailrite's excellent video on YT about measuring up the boom for one of their kits but presumably you send them the measurements and they take those into account to give you some slack where its needed ? Has anyone got any other how-to's that they found useful for DIY ?
Also, I have a bolt-rope slot for the sail, what sort of tape do I use to secure the bag in the slot ?
thanks in advance

SSG
Gosport

 

[Kwik Decision]

Hi
I would like to make a stackpack sail bag for my 9'8" boom I've looked at Sailrite's excellent video on YT about measuring up the boom for one of their kits but presumably you send them the measurements and they take those into account to give you some slack where its needed ? Has anyone got any other how-to's that they found useful for DIY ?
Also, I have a bolt-rope slot for the sail, what sort of tape do I use to secure the bag in the slot ?
thanks in advance

SSG
Gosport

I can't help with your first question, other than to say that sail makers have been known to get the dims wrong. We bought a new main and stack pack from a popular UK sail maker, and the stack pack as supplied was too small to take the sail. To their credit, they did take it back and enlarge it promptly and without quibble.

Your second question, the stack pack in question had a strip of standard dacron sail cloth, 2" or 3" wide and running the length of the stack pack forming the bottom. This being quite thin could be poked into the slot on the boom, and then the sail bolt rope slid in on top of it, holding the base of stack pack in place. Hope this makes sense, it's quite difficult to explain; I'd take a pic, but it was on our old boat.

 

[StefanSG]

Your second question, the stack pack in question had a strip of standard dacron sail cloth, 2" or 3" wide and running the length of the stack pack forming the bottom. This being quite thin could be poked into the slot on the boom, and then the sail bolt rope slid in on top of it, holding the base of stack pack in place. Hope this makes sense, it's quite difficult to explain; I'd take a pic, but it was on our old boat.

Thanks for the info, so was it like a 6" dacron section at the bottom of a v-shaped bag made of Sunbrella type fabric ?

 

[Kwik Decision]

Thanks for the info, so was it like a 6" dacron section at the bottom of a v-shaped bag made of Sunbrella type fabric ?

Yes, dacron sail cloth at the bottom, and thicker blue stuff on either side. From memory the dacron was less than 6" wide. If you're going to go down this route you may wish to experiment...

 

[Martin_J]

I'm sure I've used dacron from an old laser sail as the part along the boom under the foot of the sail..

I've also made the foot part in about four or five sections, each with a gap of maybe six inches in between.

This was to give the sail extra air in case it was put away wet. I've no idea if it helped and no idea if anyone else does that, but at least I felt better having fresh air around the underside of the sail.

Think carefully about the dimensions around it as well... our laminate main really needs to flake over the boom as it comes down... the stackpack then did need to be considerably bigger than if the sail could just have been squeezed in.

You can't go too far wrong with the Sailrite videos... oh and ensure the zip is covered (out of the sun) to reduce UV damage on the zip itself.

 

[Daverw]

We looked at making ours, but the time you added up fabric, zips etc the cost to buy from sail maker was cheape. We got from Jeckalls, very well made and also came fully fitted with all lines

 

[Tranona]

Depends on whether you have a loose footed sail or slugs. Mine is loose footed and the forward part has bolt rope for the first roughly half of the length and then slugs so that the reefing lines can pass through as in the first photo.. If you have internal reefing lines then then you can have a bolt rope the full length. If you have an attached foot then the strip of sailcloth in the groove first followed by the slugs. PITA to get it to fit properly.

Mine was custom made by Kemps with panels of mesh let in the bag for drainage and webbing with rings for attaching the lazy jacks plus extensive reinforcing on wear points. The second photo shows the overall stack pack with mast boot.

 

[Tranona]

We looked at making ours, but the time you added up fabric, zips etc the cost to buy from sail maker was cheape. We got from Jeckalls, very well made and also came fully fitted with all lines

Agree. Unless you have lots of spare time or just fancy the challenge this is a job best left to the professionals. Mine cost around £600 including the lazyjacks.

 

[StefanSG]

We looked at making ours, but the time you added up fabric, zips etc the cost to buy from sail maker was cheape. We got from Jeckalls, very well made and also came fully fitted with all lines

I will ask for a quote, good idea

SSG

 

[Daydream believer]

Number of points here.
First: Start the zip at the mast. This means that when you drop the sail you can start zipping up immediately without going aft to catch a swinging boom to engage the zip then going all the way back to the mast again.
Second. Put 4 straps across the sail about 600mm centres from the mast. These should be enough to take the weight off the zip. Also if it is rough one can just do up the straps & forget zipping. When leaving port, undo the zip then one only has to flip the straps. The straps consist of a cord loop one side & a line with a plastic ball the othet. The ball goes through the loop. This can be done with one hand whilst holding on. My sailmaker got these slightly wrong, but it shows the idea.
Third: buy awning channel from a caravan supplier & pop rivet this each side of the boom. The cover can be fitted into these channels & you do not have the hassle of trying to get the sail in the same track as the cover. It is awkward if you have a loose fitted 1/3 foot or full foot on the mainsail. So separate tracks solve the issue
Fourth. Have a separate cover to go round the mast, This reduces the amount of flapping cover when the sail is hoisted

 

[dunedin]

Number of points here.
First: Start the zip at the mast. This means that when you drop the sail you can start zipping up immediately without going aft to catch a swinging boom to engage the zip then going all the way back to the mast again.
Second. Put 4 straps across the sail about 600mm centres from the mast. These should be enough to take the weight off the zip. Also if it is rough one can just do up the straps & forget zipping. When leaving port, undo the zip then one only has to flip the straps. The straps consist of a cord loop one side & a line with a plastic ball the othet. The ball goes through the loop. This can be done with one hand whilst holding on. My sailmaker got these slightly wrong, but it shows the idea.
Third: buy awning channel from a caravan supplier & pop rivet this each side of the boom. The cover can be fitted into these channels & you do not have the hassle of trying to get the sail in the same track as the cover. It is awkward if you have a loose fitted 1/3 foot or full foot on the mainsail. So separate tracks solve the issue
Fourth. Have a separate cover to go round the mast, This reduces the amount of flapping cover when the sail is hoisted
View attachment 160722

I am confused. You seem to be making things over complicated. Never seen a stack pack with straps across the sail, and never needed any. Ours, like every other one I have seen, can hold the sail in place with the zip undone. Zip generally undone before leaving anchorage/harbour, and not done up until finished sailing for the day - again usually at anchor or in harbour.
And if lazy, sail wet or planning to leave very early next day, can be left unzipped overnight (or longer) - just exposes sail to some more UV and/or rain.
Does you sailcover lack the battens along the top edge?

Also, whilst zipping from mast to stern is probably good on a small boat, the opposite is better with a bigger boat and higher boom - start closure from the stern (which is lower) and slide zip forward - using a long string on the zipper.

 

[Daydream believer]

I am confused. You seem to be making things over complicated. Never seen a stack pack with straps across the sail, and never needed any. Ours, like every other one I have seen, can hold the sail in place with the zip undone. Zip generally undone before leaving anchorage/harbour, and not done up until finished sailing for the day - again usually at anchor or in harbour.
And if lazy, sail wet or planning to leave very early next day, can be left unzipped overnight (or longer) - just exposes sail to some more UV and/or rain.
Does you sailcover lack the battens along the top edge?

Also, whilst zipping from mast to stern is probably good on a small boat, the opposite is better with a bigger boat and higher boom - start closure from the stern (which is lower) and slide zip forward - using a long string on the zipper.

To each his own. Just because you have never seen zips starting at the mast does not mean that it is not a better solution for some circumstances.
I only have a 42M2 mainsail. But when I asked the sailmaker he agreed that it was all a good idea. I sail SH & do not want any problems. A stiff laminate sail can be awkward to get into the bag & I do not need one that is excessively large flapping around when sailing. I do have a batten in each section. I do not leave it undone when not requred as I see no point in exposing to UV. That is simply lazy- just my view.
Likewise I undo the zips when leaving port. Pulling zips with bits of string often leads to sticking if the zips get out of line.
Straps just keep everything in place until required. They take the weight off the zip & make zipping easier.
But it is the OP's choice. The ideas are out there for consideration

 

[Martin_J]

I'd not thought about a few straps as in Daydream Believer's post, but with a laminate main they might actually have been useful.

Our main was just like a spring. It didn't like staying flaked. Even in a stackpack with lazy jacks (and battens along the top outer edges), it would just spring itself upwards.. and a couple of temporary clips across the sail would have been easier than starting the zipper at the boom end sometimes.

We went for a standard sail cover in the end... Whichever, you need somewhere flat for the marking and cutting out.

 

[PetiteFleur]

One tip if you do make your own, make sure when you sew the zip in position that there is sufficient overlap when zipped up that the zip is totally covered - especially at the ends so none of the zip material is visible. This to prevent UV degradation of the material. I suspect it is made of polypropylene which is not uv resistant.

 

[geem]

I'd not thought about a few straps as in Daydream Believer's post, but with a laminate main they might actually have been useful.

Our main was just like a spring. It didn't like staying flaked. Even in a stackpack with lazy jacks (and battens along the top outer edges), it would just spring itself upwards.. and a couple of temporary clips across the sail would have been easier than starting the zipper at the boom end sometimes.

We went for a standard sail cover in the end... Whichever, you need somewhere flat for the marking and cutting out.

View attachment 160725

Laminate sails are light (and not so durable as Dacron or vectran) I can imagine a light sails jumping out of the bag. We certainly don't need straps to hold our sail in the stackpack when the zip is undone. It comes down like a guillotine with full battens and Selden cars. The 10oz cloth means it stays there.
When sailing, the lazyjacks are eased. Before dropping the sail, they are tightened to form a deeper bag.
A zip starting at the front would be useless for us. The reefing lines tend to fall into the cockpit when the sail is dropped. The first thing I do is push the reefing lines in to the end of the stackpack and zip up a couple of feet of zip to hold them in. We often don't zip up the bag fully until we have dropped anchor.

 

[alahol2]

Just one more thing to consider.
I've had both flat and circular battens in stackpacks. I very much prefer the circular cross section. I found with flat battens that they would contort themselves into odd 'S' shapes and look untidy, circular cross section battens sit in a nice straight line.
With our current stackpack the lazyjacks are tied around the battens via cutouts in the pocket. Saves those bits of webbing and stitching that rot, fray and fall off.

 

[Stemar]

On Jissel, the boom slot was too small to take the sail boltrope and an extra bit of sailcloth for the sail bag, so the sail bag got a bolt rope and the sail became loose footed with the help of a webbing band though the clew cringle and round the boom.

On more tip, unless your sail is brand new, allow enough space for a new, stiffer sail. We didn't, and the bag wouldn't zip up over the new sail. The fix was to buy a duplicate of the zip and put it on each side of a bit of fabric a few inches wide.

 

[geem]

Just one more thing to consider.
I've had both flat and circular battens in stackpacks. I very much prefer the circular cross section. I found with flat battens that they would contort themselves into odd 'S' shapes and look untidy, circular cross section battens sit in a nice straight line.
With our current stackpack the lazyjacks are tied around the battens via cutouts in the pocket. Saves those bits of webbing and stitching that rot, fray and fall off.

We found the opposite. The circular battens curve between the lazyjacks and create creases everywhere. The flat battens on our stackpack are quite thick and stiff. No issue with curves

 

[alahol2]

We found the opposite. The circular battens curve between the lazyjacks and create creases everywhere. The flat battens on our stackpack are quite thick and stiff. No issue with curves

Perhaps it's a case of ensuring that the battens are stiff enough no matter what the cross section. I guess I could have used flat battens with thicker cross section.

 

[Daydream believer]

With my set up the lazyjacks are set at the start of the season & need no further adjustment.

One other point about starting a zip from the boom end is that one might be standing on the cockpit seats, reaching up to catch a swinging boom, in a big swell, to get the tail of the zip & pull the first 6 inches to get it running. Just tightening the mainsheet does not stop the end of the boom swinging.
Off Barfleur one year in a big swell, my wife tightened the mainsheet, stood on the cockpit set to start zipping on our first cover, She accidentally kicked the cleat on the traveller car, releasing it. The boom swung her out over the guard rail. The back of her knee hooked on the wire but she managed to hang onto the boom with her body over the side until the next wave swung it back & threw her into the cockpit on the other side.
On the systems I have seen, one cannot just pull a cord on the zipper, without getting the zip properly started a foot or so in the first place. I had a newbie crew who went to zip up. He lost his balance whist standing on the seat & ripped the zipper clean off the zip as the boat rolled.
After that I had the zip completely changed, zipping from the mast & adding straps.

As for reef lines, I can pull mine in from the boom. But as mine have minimal friction this is not an issue when hoisting the sail. For some I can see that might be