Sail design and home sail making [Archive]

keyhavenpotter

23rd September 2008, 08:44 PM

I really want to make my own lug rig mainsail over this coming winter for my planned Storer build.

Although few dinghy builders seem to want to make their own sails, here we have a group who already do for the PDR's. Perhaps we can build on that.

If we developed the panel layouts together to make a good generic lug mainsail, we could then adapt the sizing to Beth, Goat, PDR and RAID41.

There are just such a lot of "words" to understand, such as broadseaming, luff round, cord ratios etc etc.

I have recently been recommended a book which has begun to de-mistify all these words for me. The book is "The Sailmaker's Apprentice" by Emiliano Marino. Here in the UK it costs retail just over £20, but buying on-line I have just paid about £9 including delivery and it is the best £9 I have spent for a long time. There may be other good books people can recommend, but this one is really good.

If members all read the same book, then we could clarify any page entry together.

http://www.amazon.com/Sailmakers-Apprentice-Emiliano-Marino/dp/0071376429

The other on-line resource we could use is the free software

http://www.sailcut.com/Sailcut_CAD

We could actually design the lug main on this software and build it. We have to learn to understand, and choose as inputs to the software

Top depth %
Mid depth %
Foot depth %
Twist degrees
Sheeting angle degrees

as well as the actual sail dimensions and panel layout.

With MIK's help we could all learnt a lot about lug mainsail design and save loads of money!

Brian

m2c1Iw

23rd September 2008, 09:41 PM

G'day Brian,
I have been playing with Sailcut and Sailform the problem is I have no idea what I'm doing:rolleyes: need to do some study, so appreciate the tip re the book.
I'm yet to come across anything online that provides info for the novice I also suspect sails are a bit like hulls one needs to examine the ideas of others and tweak.

Experimenting with sail cuts could become as addictive as boat building.:U

Cheers
Mike

Boatmik

23rd September 2008, 10:22 PM

Howdy ... could do.

Be aware that the OZ PDRacer rules do not allow panel shaping/broadseaming or any other cloth than polytarp.

After seeing how nicely Gyula and Dan's lugs looked i would have no hesitation to suggest a much simpler sail. Then it is a matter of just defining the boom and yard round.

http://farm4.static.flickr.com/3148/2633526022_ccc9d808e7.jpg

http://farm4.static.flickr.com/3104/2830062314_b85d822dc4.jpg

So while polytarp is all that is allowed for the PDRacer, why not just glue or sew up a flat dacron sheet and cut it out with the right round.

Save a bundle and 250000 lasers can't be wrong ... they use only edge round too.

Makes designing a sail very simple. For those who think that they may not work very well ... look at the videos (http://www.storerboatplans.com/video.html).

My idea is to have stock sail designs available to purchasers of the plan much like we do with the OZ. If you intend to do something more eleborate and look into design we could have three variations of homemade sails for the RAID41.
1/ Flat polytarp sails like the above - they take one evening to stick together then an hour or two on a sewing machine making them permanent.
2/ Same design but proper sail cloth - a bit of easy labour making up a big flat panel out of regular sailcloth to use the same method as the polytarp sail.
3/ A full fledged, properly designed sail with edge shaping and broadseaming.

The first option would probably allow sails to be made of the good quality polytarp for about $60
Second option maybe $250-300
Third option $300 to 350.

This is the biggest single cost saving for the boat.

MIK

keyhavenpotter

23rd September 2008, 11:01 PM

Thanks Michael, I had no idea that the Laser only used edge rounding. I guess it does have the length of the mast to "edge" with. So we can create a simple shaped dacron lug mainsail which we should all be just about able to make.

Great start.

The Laser uses a luff sleeve, could our Lug Main have a gaff yard sleeve and the boom be in a sleeve. I have wondered about this for a while. Would be a very clean look. Much nicer than all those grommets and string.

Leave openings for halyard, mainsheet and kicker attachments.

The other thing is my local lug sails are very full as shown in my Flicr pictures. I will be racing Raid41 locally. Will a simple sail such as this be able to hold it's own against the local very developed lug sails. I really want to show her off against the other local boats ( that's the racer in me).

It will be best for the class I guess, to keep the sail easy to make and low cost. Sort of one design- ish like the PDR but accepting dacron and edge rounding.

Brian

Boatmik

23rd September 2008, 11:51 PM

I think a standard sail with edge rounding only and if someone wants to go to a specialist lug rig sailmaker ... I am not about to stop them.

MIK

keyhavenpotter

24th September 2008, 02:07 AM

How about a standard sail and a home build racing sail too. After making the standard sail, with the increased confidence in sail making and sailing, then have a go at the racing sail. Using the same spec Dacron and sizing, adding broad seaming would not add to the cost in anyway, so keeping to the spirit of low cost fun. Going to a local sailmaker would probably cost more than the whole boat will cost.

I am sure only a few builders would go this route, and people supplying sails for your designs would still have almost as many orders. Possibly more in the long run.

I just thought it would be fun to explore shaping and thus learn even more about my favourite lug rig. Brian

Boatmik

24th September 2008, 09:13 AM

keyhavenpotter

25th September 2008, 08:57 PM

A nice small, simple, edge shaped sail to cut our teeth on and learn the techniques would be the mizzen sail on RAID41? Makes sense to risk the least amount of material on a first attempt. Happy to wait until dimensions of sail finalised and will keep reading up until then. Brian.

Boatmik

25th September 2008, 09:27 PM

Focus on the construction Brian, The design is pretty straightforward and I can provide the whys and wherefores in this thread if you like .. when we get to that point.

The PDRacer lug is bigger than the one on the RAID by the way!

MIK

keyhavenpotter

25th September 2008, 09:44 PM

RAID41 has a mizzen as well, and possibly a mizzen staysail and a genniker!

Have to make her go in the very light wind strong ebbtide somehow. Getting flushed out through Hurst Narrows is always a worry!

Brian

Boatmik

25th September 2008, 10:30 PM

I have notorised the drawing to remind myself to think of jibs/gennekers. Might slip the mast back behind the bulkhead instead of in front to give a bit more J.

or maybe look at a tiny stub bowsprit so there is no staying required..

Will look .. ok?

MIK

keyhavenpotter

25th September 2008, 10:54 PM

Ok.

Not sure about jibs though. Perhaps a self tacking blade jib to avoid the constant catching on the front of the lug's boom and also increase visibility.

A nice flatish lightweight genneker could be useful. Adds a turbo charger for local racing, and more importantly a way of making over the tide in very light winds.

After all, it makes a lot of sense to have a lot more sail area off and down wind, than what was the right amount going up to the windward mark. A three sail singlehander!

Short bowsprit sounds good.

Brian

Boatmik

25th September 2008, 11:07 PM

It will firm up one way or another, but I am thinking of something that you pull up only when you think you can use it and are not planning to spend a lot of time changing tacks with it up. Turbo when reaching or shy reaching or needing that extra half knot against the tide.

MIK

keyhavenpotter

25th September 2008, 11:45 PM

Absolutely spot on!

Brian

keyhavenpotter

5th October 2008, 02:33 AM

m2c1Iw

6th October 2008, 07:00 PM

Although I have been reading about sail making - as usual struggling to get the concepts into my head. It's just amazing how seeing a sail made on video makes understanding so much easier. Here are sail making videos on YouTube. Not sure what the wife is going to say about sticking "picks" in the lounge floor!

http://uk.youtube.com/results?search_query=sailmaking&search_type=&search=Search

Brian

Brian,
Nice find, that is a really good set of instructional vids and well done to the bloke who put them together.

Hmm....our lounge floor is slate I wonder if SWMBO would mind a few sheets of particle board for a while. Of course I'd give them a coat of varnish so it looked good:roll:. We have a split level so I can have simulated sewing machine pit:D

Mike

Boatmik

6th October 2008, 10:32 PM

Why simulate when you can borrow a chainsaw. Then you can cover the hole with one of those bits of particleboard.

MIK

joern

7th October 2008, 01:11 AM

Yep,

I would agree with that completely. I can do the simple edge shaped sail design, but someone else will have to work out the multipanel seam shaped (broadseamed) patterns using a program as you describe. I can give you the parameters for fullness and twist if you want to have a fool around with the program.

Michael

Hi,

I played a bit with sailcut. Mik, what are the parameters for fullness and twist ( and how is the matching stiffness of yard and boom)?

Greetings - Jörn

Boatmik

8th October 2008, 12:05 AM

Howdy,

I would tend to be quite conservative for a first sail. Underestimate both the depth and twist of the sail.

I would choose a fullness around 10 percent for a first sail. Better a little bit too flat than too full.

Twist I would expect around 10 degrees.

Draft about 40% back or a little under that. I think that is the general range for headsails ... and this will be at the front of the boat like a headsail.

Yard and boom bend .. about 30mm. For the yard it is centred halfway along. For the boom about 1/3 back from the front end.

keyhavenpotter

8th October 2008, 12:37 AM

Boatmik

8th October 2008, 01:02 AM

Hi

have put approximate dimensions for RAID41 mainsail into Sailcut CAD, with your figures from above post. When you rotate the sail horizontally and vertically it looks quite nice. The programme allows fullness at three points up the sail, so I entered 10% for the foot, 7% mid point and 6% top section.

Guessed gaff angle at 20 degrees, looks about right, and sheeting angle for a lug main with no jib as 15 degrees?

Seems to only export to more complex ,dxf files etc and not .jpg so I could post here.

I really like the revolving feature that lets you see the shape of the sail from all angles. Broad seaming does not look so intimidating after watching the sailmaking videos.

Brian

Sheeting angle for the front sail of most boats is 10 degrees. Slower boats can go a bit wider ... maybe 12deg.

Sounds too flat in the top but that might be all that is possible with the amount of twist. If you can squeeze a bit more fullness in then that would be nice. If you are setting up with the vanging systems you have been using on your boats then maybe can come down to 8 degrees twist ... though for people who are not going to be working quite as hard in getting sails trimmed right then the flatter in the head option will be more forgiving.

I can check the "gaff" angle in the morning .. after midnight here.

You can email DXF files to me and I can convert them and put them up for you. Other way is if you can convert documents to PDF fles you can copy and paste in to a graphics program and save as a jpg.

MIK

keyhavenpotter

14th January 2009, 08:48 PM

Have now worked up a sail design for a four sided lug sail and the triangular mizzen using Sailcut4. Having chosen fullness, twist, panel layout etc it is then very quick to create a sail with different dimensions using the same fullness etc. A version of my Scow sail only took a few minutes. One for the Goat, if given the dimensions would also only take a few minutes.

My local supplier of remnant sailcloth turned up trumps. Enough 4 oz Dacron to make two sets of Raid sails was only £53 - £26.50 per set must be as cheap as Polytarp?

When I began this process I wondered about avoiding sewing. Boat builders are used to glues, fitting curved panels but not sewing. Could I find a glue for Dacron? Well, yesterday I came across this interesting piece about the strength of glued seams on dacron being stronger than sewn seams.

http://www.cruisingworld.com/how-to/projects/magic-goo-to-the-rescue-201615.html

The product is 3M 5200 FC and can be obtained in small dispensers at around £6 cost.

http://solutions.3m.co.uk/3MContentRetrievalAPI/BlobServlet?locale=en_GB&univid=1114277160784&fallback=true&assetType=MMM_Image&blobAttribute=ImageFile&placeId=7BC6E48B1800BAE180A88E492700006A&version=current

The concept would be to use a double sided 1/4" tape in a 3/4" seam, build the sail - only 4 seams in my panel layout - check out the set then apply the glue to the open seams.

Anybody tried this??? Just think glued seams might be more popular with builders rather than sewn seams. Keeping control of the glue will be the main issue.

Brian

Boatmik

15th January 2009, 09:01 AM

Howdy Brian,

It is a big and interesting area.

The PDR people do use hardware materials to tape some of their sails together.

Also many of the highest tech sails are taped together too with no stitching.

There are a few different grades of double sided tape ranging from ones that are used to hold the sail together temporarily through to ones that will hold it together permanently.

My sailmaker (when I was doing the PDRacer research) said that the best grade of tape (expensive) works well with sails made of laminated cloth (ie non woven film - mylar - by alternating the panels you can usually make sure that you are bonding the film side of one panel to the film side of the next at the seam) but the cheaper tapes are not terribly reliable, particularly in Australia's hotter climate.

He said he only trusts the best tape and only trusts it on laminated cloths where it can bond to the mylar side.

He did not mention the 5200 - I think the convenience of the tape was a big factor for a commercial loft.

Michael

keyhavenpotter

15th January 2009, 09:11 AM

Hi MIK

thinking along the lines of using a cheaper tape as an aid to assembly and then glueing with a bead of 3m 5200. I think the stronger tape is sold by Sailrite as Super Seam-Stick. Have not found that in the UK yet.

Tod Bradshaw kindly posted these comments on the WB forum.

"Dimension Polyant Sailcloth has been selling an air-powered hot glue gun to use in conjunction with a basting line of 1/4" tape, instead of stitching, for quite some time. You baste one side of the seam with the seam tape, stick the nozzle of the gun under the flap, shoot a bead of glue in there and roll it down. Drawbacks are the cost of the gun ($2K) and that you need to do a lot of seams at once, because once opened, the glue cartridges have a fairly limited "pot life". If you could control the excess and had space for it to dry flat, 5200 might do the same job just about as well..."Honey, do you mind if I spread this sail out on the living room carpet for a little while?"......"

Brian

Boatmik

17th January 2009, 08:39 AM

Sounds pretty much like what we do with the PDR sails .. dry assemble with the cheaper tape .. then we stitch.

There will probably be a requirement for the amount of bonded seam width relative to the sailcloth strength/weight.

MIK

keyhavenpotter

21st January 2009, 10:10 PM

Been struggling with my back but thought I would try laying out the panels on my sailcloth last Sunday.

Managed to clear enough room in the lounge, really surprised just how long the leach is when it's laid out in front of you in the flesh. 16' sees huge laying there.

Since I cannot spike the cloth to the lounge floor, tried parcel tape, learned I need to use far more to hold it steady whilst I worked on the dimensions.

After 15 minutes my back went and am now in twice the pain - stupid or what!

My cloth is actually 1500mm wide and I had planned on 700mm panels to keep it looking nice. Those seams look so long though. Wondered about simplifying the layout and using the cloth at 1500mm. This gives only two vertical panels, and thus only one joining seam. It suits the PDR/RAID41 simplify ideas, and also MIK has remarked about the Laser being a flat sail. The Laser does have mast bend though.

I have tried a layout in Sailcut4 and it looks nice enough in the drawing, the question is - could it work in the flesh? It would be great if it did - there is only one seam to sew/glue, so much easier to make and less to split. Presumably the shape would not be as good as a 4 panel sail, but would it be good enough? Hope so.

b.o.a.t.

22nd January 2009, 01:02 PM

MIKs lugs have flexible boom & gaff to do the same job as the Laser's flexible mast.
As he seems to have designed these spars around a flat-cut sail, I wonder if they
would need re-sizing around a shaped sail ?
cheers
AJ

Boatmik

24th January 2009, 07:39 AM

Howdy Brian,
It depends on what you are shooting for. If you are following your idea of the ultimate sail .. the narrower panels are better. But it would be possible to get a reasonable pair of sails with a simpler layout though a bit of performance would be lost.

One thing though .. this boat will be shown off a bit in the UK ... so depends on your "marketing" angle. Is it a cheap homebuild with polytarp sails or something that will make box boats appeal to the mainstream?

Michael

keyhavenpotter

24th January 2009, 08:21 AM

Just trying to shoot for a low cost nice dacron sail to go with the low cost polytarp already available. Seemed a nice thing to have for a nice boat that's all.

the vertical cut means the leach panel is 16' long plus room to work around brings it up to needing a 20' plus flat floor to cut the panel out. Too long.

Re-laying the sail out to a horizontal cut, with 750mm panels ( my cloth is 1500) makes the maximum panel length only 9'. much easier to handle, although there are now seven panels. I will check later but I think the 750mm panels size puts the first two panel seams in the right place for fitting horizontal battens into the seam. This also sets the place then for the two reefs for the sail.

Then tried cutting down the number panels by specifying 1250mm cloth. This cuts it down to just 4 panels. Also falttened the head and slightly flattened the mid section. Very confused now, help and guidance much appreciated.

The actual panels curves are minimised also as you can see here in the pdf output. Perhaps this is the way to go?

Brian

Boatmik

26th January 2009, 07:47 AM

Howdy Brian,

I would always go for the minimum number of panels except for a raceboat. As you are club racing I would suggest going for the best performance option.

It will be easy enough for me to draw up some basic edge shaping only sails that could be made of polytarp or out of dacron. This will cover the simple option.

But the gap is for a nice sail I guess.

Michael

keyhavenpotter

27th January 2009, 07:53 AM

Todd Bradshaw has been hugely helpful in trying to explain sail shaping to me on the WB forum.

http://www.woodenboat.com/forum/showpost.php?p=2083841&postcount=107

Brian

keyhavenpotter

1st February 2009, 06:28 AM

Here is a file illustrating the sail shape achieved using Sailcut4. This is a cross cut version and is getting very close to the final version. This cross cut style reduces the maximum length of the panels down to just under 9' from the longest panel on the vertical layout of 16'. Much easier to layout in the lounge!

Brian

Boatmik

1st February 2009, 11:55 AM

Excellent progress! It also means that a mistake in one panel will waste less cloth.

Michael

Sprattuk

11th May 2009, 03:29 AM

hey guys, just stumbled across this site and thought i might be able to help.... im a sailmaker in the UK and thought i might be able to offer some assistance! I've made sails from your little laser sail (which by the way does have shape in the broadseems) to sydney hobart winning sails including materials from cotton to cuben carbon! im pretty familiar with the freeware sail design software and could get hold of any tools or materials you might want. if given the measurements i could knock you up a computer design for both race and cruise spec.

Matt

keyhavenpotter

11th May 2009, 03:56 AM

Matt, that's really kind to offer assistance. Wish you had been here a while back!

We have a polytarp sail design in place for RAID41 from the PDR polytarp lug riig.

I have a broadseamed design which was designed on Sailcut4 but would be great to sort out for future builders, and panel shapes added to the RAID41 build drawings.

To reduce time spent on the "loft" floor after a back injury, for the prototype I am making a "polytarp" design sail but using 4 oz dacron. Just completing the sewing of both sails right now. Just stopped for a breather and saw your post.

Where I would be really grateful for advice and any assistance is the next stage.

I need to make my mind up whether to hire star tooth grommet tools from Point North Fabrics and what size to choose as well, or go ahead with my original plan to have soft clews using webbing at the corners. And also whether to use grommets or webbing for the yard and mizzen mast lacing.

Just running out of white V69 thread and need a bobbin of black V69 if I go ahead with the webbing idea.

Brian

keyhavenpotter

11th May 2009, 04:54 AM

Just completed the sewing of all panels and the two batten pockets. Really does make you realise how much work sailmakers get through to make our sport so pleasurable.

http://farm4.static.flickr.com/3381/3518547661_c7c2ba90b2.jpg?v=0

Brian

Sprattuk

11th May 2009, 06:37 AM

If you can let me know Luff, Leech, foot and head measuremnts i'll have a quick look at similar sizes designs for corner specs. Soft eyes are best if you've just spent 4 weeks varnishing your spares, but it would put a huge strain on a domestic machine. We use small size 'oo' eyes for lacing to the mast and gaff which seems to be the best solution. Do you know which supplier your 4oz dacron came from? Also how much leech hollow have you put in and how many layers you've put in your patchs? these are all simple cheap things that can make the sail last twice as long. Just checked out 'point north fabrics' never seen there site before, the tool hire seems really reasonable but everything else seems very over priced. i'd love to help you all get a cheap reliable (and quick) sail!

keyhavenpotter

11th May 2009, 06:55 AM

The cloth is actually from a local chap who sells through eBay.

Sail area of the main is 7.25 sq m and the mizzen only 1.69. Had planned on 00 for the lacing, think it was 0 for the corners. The USA numbers seem to be different for the same sizes. I think Todd's 0 and No2 are our 00 and 0?

Each corner has 3 patches, so 4 layers in total. The foot has a full length added panel so 5 layers for the tack and clew. Battens are where the reefing clews are, so similar numbers there as well.

Have an industrial hand driven sewing machine for webbing sewing. Our normal home machine did ever so well on the sails. Struggled a bit on the corners but managed with some extra hand turning assistance. When we looked at the drive system under the machine it seems to be all metal. Our better machine actually failed sewing a dinghy cover when the old tired plastic worm gears failed.

I have enough material still to make another full set of sails later on, with full broad seaming. However Raid41 is very narrow and must be easily driven upwind, so fairly flat sails could well suit her.

Brian

Sprattuk

11th May 2009, 07:46 AM

For the clew i'd use a No. 2 (about 12mm inside dia). normally we'd drop now to a size '0' (10mm inside dia) for the tack but as your patch's are the same thickness i'd try for the No.1(11mm inside dia) for tack, and throat. Sails looking good from the pictures!! i guess its a plain luff? no rope pulled through? if so id suggest webbing loop at the head. Check out our website www.suffolksails.net.

keyhavenpotter

11th May 2009, 08:11 AM

The main sail luff has 3mm Dyneema running up the inside from tack to throat. Our local lug sails use 6:1 downhauls so used to a great deal of tension from tack to throat. The throat will be fixed somehow to the front of the yard ( yet to workout for this sail, probably with an eye on top of the front of the yard) , so all the tension stops there. The head will then be adjusted separately.

Thanks for the kind words, just don't get too close!

Brian