Well the new mainsail is going great, but the old stack pack on my boat finally spat the dummy. The extra bulk of the new sail compared to the old one has put too much stress on everything, and it basically exploded last weekend. I'm not surprised...

We're planning on building one ourselves, but I thought you guys might have some experience and advice before we dive in? Best suppliers for materials?

Weathermax as a material, slugs along an open bottom (loose footed main), heavy duty zip with a cover flap, and lazy jacks built in. Rather than have the vertical mast zip directly forward on the mast, we plan to wrap it all the way around and locate the zip in line with the main halyard where it enters the mast sheeve.

Mine was professionally made but I have had it off for major repairs and modifications several times over the years.
My next one will be in Weathermax. I have a loose foot mainsail and there are a few feet of bolt rope in the boom, the ends are open. I used to have a zip on the first third of the cover. the rest is just the plastic tubes pulled in to close the gap and keep the sun off the sail. I do tie the plastic tubes together when I pack up. I replaced the zip a couple of times but then ditched them in favour of plastic clips. 50mm seat belt material along the edge where the zip was and 20mm webbing and clips now hold the cover closed. The front is open with just 20mm webbing and clips to hold it against the mast. Air just blows straight through. In the photo, you will notice the 50mm webbing loops on the lower edge near the boom to hold the reefing lines tidy.
Use straight stitching to reduce the chance of abrasion.
Check out sailrite.com for info and videos, plans etc. Ignore the old headsail up there at the moment!

Thanks, that looks pretty tidy Ramona. I think it was you that recommended Weathermax in an older post wasn't it? So are your battens pvc tubes, what dia. are they? My old pack has two flat sail battens that aren't quite stiff enough, they warp quite a bit when the lazy jacks are pulled on hard. When you say the wind just blows through the front, can you do that without getting UV exposure on the luff of the sail ok? I see the sense in getting some airflow front to back. Also a couple of designs I googled had an inner layer of mesh sewn into the bag, presumably a tad smaller so that when the pack is properly deployed, an air layer is created inside between the mesh and the inside of the canvas, I quite like that idea too.

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2bish said..
Thanks, that looks pretty tidy Ramona. I think it was you that recommended Weathermax in an older post wasn't it? So are your battens pvc tubes, what dia. are they? My old pack has two flat sail battens that aren't quite stiff enough, they warp quite a bit when the lazy jacks are pulled on hard. When you say the wind just blows through the front, can you do that without getting UV exposure on the luff of the sail ok? I see the sense in getting some airflow front to back. Also a couple of designs I googled had an inner layer of mesh sewn into the bag, presumably a tad smaller so that when the pack is properly deployed, an air layer is created inside between the mesh and the inside of the canvas, I quite like that idea too.

The pvc tubes are 25mm. The front straps around the mast hold the front edge in close to the mast. The sail is always in the shade.

Yes, Missus made ours out of Sunbrella. Sleeves either side take 1" plastic conduit to attach the lazy jacks to.
You must use UV resistant cotton.
The difficulty amatuer sewers have is making the zip cover lie flat on the zip, it almost always sticks up vertical.
She made it on our ancient Necchi sewing machine.

This keeps the swallows out...

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Offthegrid said..


This keeps the swallows out...

Ahh, so it's not just me they like then!!!

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Ramona said..
Mine was professionally made but I have had it off for major repairs and modifications several times over the years.
My next one will be in Weathermax. I have a loose foot mainsail and there are a few feet of bolt rope in the boom, the ends are open. I used to have a zip on the first third of the cover. the rest is just the plastic tubes pulled in to close the gap and keep the sun off the sail. I do tie the plastic tubes together when I pack up. I replaced the zip a couple of times but then ditched them in favour of plastic clips. 50mm seat belt material along the edge where the zip was and 20mm webbing and clips now hold the cover closed. The front is open with just 20mm webbing and clips to hold it against the mast. Air just blows straight through. In the photo, you will notice the 50mm webbing loops on the lower edge near the boom to hold the reefing lines tidy.
Use straight stitching to reduce the chance of abrasion.
Check out sailrite.com for info and videos, plans etc. Ignore the old headsail up there at the moment!

Ramona, I have to make a new one for my mizzen, zips add extra nuisance with a gaff it's much easier to leave the peak halyard set up, I was planing on useing a sewn on Velcro arrangement. What sort of plastic clips are you using ?

Have a look at the Sailrite website, they have details on DIY Projects!

Have a look at the Sailrite website, they have details on DIY Projects!

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samsturdy said..
Yes, Missus made ours out of Sunbrella. Sleeves either side take 1" plastic conduit to attach the lazy jacks to.
You must use UV resistant cotton.
The difficulty amatuer sewers have is making the zip cover lie flat on the zip, it almost always sticks up vertical.
She made it on our ancient Necchi sewing machine.

Thanks Sam, we plan on using weathermax and the right thread definitely. That issue with the zip flap is interesting, is it some kind of thread tension thing? I'd imagined using a lengthways folded strip to give it a bit of weight, I'll check my existing one to see how that's constructed too.

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Stockie said..
Have a look at the Sailrite website, they have details on DIY Projects!

Yep good one, I'll revisit that for a look.

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woko said..

Ramona said..
Mine was professionally made but I have had it off for major repairs and modifications several times over the years.
My next one will be in Weathermax. I have a loose foot mainsail and there are a few feet of bolt rope in the boom, the ends are open. I used to have a zip on the first third of the cover. the rest is just the plastic tubes pulled in to close the gap and keep the sun off the sail. I do tie the plastic tubes together when I pack up. I replaced the zip a couple of times but then ditched them in favour of plastic clips. 50mm seat belt material along the edge where the zip was and 20mm webbing and clips now hold the cover closed. The front is open with just 20mm webbing and clips to hold it against the mast. Air just blows straight through. In the photo, you will notice the 50mm webbing loops on the lower edge near the boom to hold the reefing lines tidy.
Use straight stitching to reduce the chance of abrasion.
Check out sailrite.com for info and videos, plans etc. Ignore the old headsail up there at the moment!

Ramona, I have to make a new one for my mizzen, zips add extra nuisance with a gaff it's much easier to leave the peak halyard set up, I was planing on useing a sewn on Velcro arrangement. What sort of plastic clips are you using ?

I don't think Velcro would last any longer than a zip. The velcro would collect crap on the loops too. I use the normal 20mm clips that are readily available. Spaced about 150mm apart.

www.ebay.com.au/itm/20mm-plastic-side-release-buckles-ITW-FASTEX-webbing-strap-quick-release-clips/253556213281?hash=item3b0920c621:m:mP0miu0xlgUwbtFB7rQcenQ

i would go with clips too, which is what i've used on the mainsail/boom cover that i made to replace our stack pack. when you sew the webbing for the clips, i suggest making one side adjustable.

zips are great when they are new but the long stitches are a weak point and it's much harder to repair and replace them in situ. agree with Ramona about velcro too...

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2bish said..

samsturdy said..
Yes, Missus made ours out of Sunbrella. Sleeves either side take 1" plastic conduit to attach the lazy jacks to.
You must use UV resistant cotton.
The difficulty amatuer sewers have is making the zip cover lie flat on the zip, it almost always sticks up vertical.
She made it on our ancient Necchi sewing machine.

Thanks Sam, we plan on using weathermax and the right thread definitely. That issue with the zip flap is interesting, is it some kind of thread tension thing? I'd imagined using a lengthways folded strip to give it a bit of weight, I'll check my existing one to see how that's constructed too.

I'll have to ask Missus about the zip cover lying flat. I took the stack pack to a local cover maker to have the eyelets stamped in ( Missus could only put in small ones ) He made the remark about the zip cover, I said Missus was a dressmaker and new about these things.

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Offthegrid said..


This keeps the swallows out...

Good Idea, I'll add something to cinch up the end if needed.

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Ramona said..

woko said..

Ramona said..
Mine was professionally made but I have had it off for major repairs and modifications several times over the years.
My next one will be in Weathermax. I have a loose foot mainsail and there are a few feet of bolt rope in the boom, the ends are open. I used to have a zip on the first third of the cover. the rest is just the plastic tubes pulled in to close the gap and keep the sun off the sail. I do tie the plastic tubes together when I pack up. I replaced the zip a couple of times but then ditched them in favour of plastic clips. 50mm seat belt material along the edge where the zip was and 20mm webbing and clips now hold the cover closed. The front is open with just 20mm webbing and clips to hold it against the mast. Air just blows straight through. In the photo, you will notice the 50mm webbing loops on the lower edge near the boom to hold the reefing lines tidy.
Use straight stitching to reduce the chance of abrasion.
Check out sailrite.com for info and videos, plans etc. Ignore the old headsail up there at the moment!

Ramona, I have to make a new one for my mizzen, zips add extra nuisance with a gaff it's much easier to leave the peak halyard set up, I was planing on useing a sewn on Velcro arrangement. What sort of plastic clips are you using ?

I don't think Velcro would last any longer than a zip. The velcro would collect crap on the loops too. I use the normal 20mm clips that are readily available. Spaced about 150mm apart.

www.ebay.com.au/itm/20mm-plastic-side-release-buckles-ITW-FASTEX-webbing-strap-quick-release-clips/253556213281?hash=item3b0920c621:m:mP0miu0xlgUwbtFB7rQcenQ

Thanks Ramona, that makes good sense to me.

I had my zip give way at the mast end so my sail maker put in a 1m section of zip at the mast end zipping up away from the mast.
My main zip is set up to do up from the outer end of the boom.

I later found that this was a really good idea because when I went to the mast to get the mainsail down I could just zip up that 1m section, where most of the sail was anyway, and this would contain the sail until I had anchored.

I didn't have to do the whole zip from the end of the boom to contain the sail.

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nswsailor said..
I had my zip give way at the mast end so my sail maker put in a 1m section of zip at the mast end zipping up away from the mast.
My main zip is set up to do up from the outer end of the boom.

I later found that this was a really good idea because when I went to the mast to get the mainsail down I could just zip up that 1m section, where most of the sail was anyway, and this would contain the sail until I had anchored.

I didn't have to do the whole zip from the end of the boom to contain the sail.

Interesting fix for you, but my lazy jacks already do the containing when the sail is dropped. I then take the halyard down and around a cleat on the mast and take up the slack to stop the sail from lifting in gusts, it only takes 20 seconds, so probably no longer than zipping your short section, so I don't see an advantage for me.