Johannah Posted February 18, 2003 Report Share Posted February 18, 2003 Paul, I plucked the following quote out of a lively discussion on the Wooden Boat forum regarding the proper set of lug sails. The whole discussion is intriguing, but Todd Bradshaw's comments (attack) on poly sails, especially for Weekenders, sounds important. Trouble is I don't understand the terminology. What is the scrim and how does it have direction, right or wrong? Is this guy making a valid point that the homemade poly sail folks need to know?? "Todd Bradshaw . Member # 1928 posted 02-17-2003 07:19 PM I'm not going to waste much time arguing sailmaking with someone who isn't one, never has been one and probably never will be one - but the farther you go, the more you show your lack of knowledge on the subject. It's true that in general (though not always) the less your spars bend, the better, but making spars twice as heavy as you originally thought they needed to be, rather than learning how to cut a sail in the first place is stupid. Putting the "leech before the luff" is building a small boat sail before measuring the spars for bend or at least taking it into account before you start cutting fabric. It's standard practice. To go along with it, a good deal of the reason that some people have such serious luff sag problems on lugsails and have to run such high downhaul tensions is that their luffs are improperly reinforced and/or cut wrong in the first place. The same thing happens when they try to build a jib and aren't aware of how you compensate for headstay sag. On small sails, the fabric's weight and stability is often much higher in proportion to sail size than it is on sails for bigger boats. It is thus much less forgiving of some of the shaping errors that you can get by with on larger sails and cutting and shaping can be quite tricky. I find that the small sails that I build now often present much more intricate shaping problems than the big Kevlar/Mylar radial multihull sails that I used to build. Fabric weight and stability is one big contributing factor. The other is spar bend. I've pretty much held my tongue here over the years with regard to poly-tarp sails. This forum seems to support both those who seek to do work of the highest quality and those who for lack of a better term and with no insult intended, lean toward more quick-and-dirty boatbuilding with wood being the primary component. The two sides seem to get along admirably and there are those here who practice both diciplines. Poly-tarp isn't all that different from the Mylar/polyester-scrim-based sail fabrics used for racing and beach cat sails. The real sail fabrics are more durable and more stable, but the principle is pretty similar. My biggest complaint with the poly-tarp and duct tape set has never been the material, it's the design and the cuting of their sails. Whether it's a whole website full of pics of Weekenders where the scrim in the "sailcloth" is all pointing the wrong direction or pictures of a boat that sailed down the east coast with a polytarp jib with a big bag right behind the luff wire, many of these sails demonstrate a profound lack of knowledge of how to cut a sail out of any material. I spent about 20 minutes the other day on Michalak's website reading an essay on how to add darts to polytarp sails to improve their shape. It had formulas. It had drawings. It had pictures. After getting my mind thoroughly boggled by the intensity of it all, my reaction was "Sailmakers don't usually use darts because they aren't very strong and tend to make lumps in sails. This is more complex than learning how real sails are shaped. Why not just learn to do it right?" I have no idea what Milli's sail is made from, who made it and whether they made it properly. In any case, the advice that I gave is based on 23 years of making small boat sails. Perhaps I'm wrong to assume that people want to know the correct way to build them in the first place. The best idea for this boat is still to do nothing and try the sail out on the water before changing anything." Sorry it's so long, but I think it's worth reading. Quote Link to comment Share on other sites More sharing options...
Tim Diebert Posted February 18, 2003 Report Share Posted February 18, 2003 Wow. That fella had a lot to say...but seemed to forget to say just exactly what the 'scrim' direction should be....and how a poly sail should be made. I will be replacing my poly main this year...with another poly main, but am graduating to a 'real' headsail cut down from an old jib a friend gave me this winter. I know Paul is in the real sail business, and if I had some real money he would be the man to get it...but I am wondering if he will enlighten us with his oh so infinite wisdom on all things Poly. (looking for another avatar to irritate further) :vamp: Quote Link to comment Share on other sites More sharing options...
Johannah Posted February 18, 2003 Author Report Share Posted February 18, 2003 Tim, you are enjoying way too much the effect of your visage on the assembled hords! I actually got to enjoy wondering if you were going to appear on the left any minute. We anticipate with dread and wonder your next avatar. :shock: Quote Link to comment Share on other sites More sharing options...
Tim Diebert Posted February 19, 2003 Report Share Posted February 19, 2003 ....just for Jo. Quote Link to comment Share on other sites More sharing options...
Frank Hagan Posted February 19, 2003 Report Share Posted February 19, 2003 I always thought it would be interesting to see people express themselves with avatars, but you have brought it to a new level! Quote Link to comment Share on other sites More sharing options...
Guest EdWoerle Posted February 19, 2003 Report Share Posted February 19, 2003 To paraphrase an ancient Chinese proverb... " 'Tis better to remain silent and be thought arrogant, than to speak up and remove all doubt" (The original replaces arrogant with ignorant, but either fits) :wink: :wink: Ed Quote Link to comment Share on other sites More sharing options...
Tim Diebert Posted February 19, 2003 Report Share Posted February 19, 2003 'Tis better to remain silent and be thought arrogant, than to speak up and remove all doubt ...I not entirely sure there Ed....but them might be fightin words. Quote Link to comment Share on other sites More sharing options...
Paul J Posted February 19, 2003 Report Share Posted February 19, 2003 Yo Jo. Just had to say that. Scrim the dreaded scrim issue, save me. :wink: You know you made me go over and try to read that thread. It's way to early in the morning for that discussion, my head hurts already. OK I will talk about scrim, that's the stuff they do on whale bones. Oh sorry thats scrimshaw, oops. I told you it was early. Seriously, well I'll try to be serious anyways but no promise's. Scrim is a re-inforcing that is in laminated sheet material. Does that help. I guess not. Before I go to far here [more than likely to late already to worry about that now] lets look at what is called "plain weave". What's plain weave? I just knew you where going to ask that. Plain weave is the weave most fabrics are made with. It has a warp and fill, Yeah, yeah, whats warp and fill. Warp are the fiber bundles that run the length of the fabric and fill are the ones that run across the fabric. Or 0 and 90 degrees. Now scrim is the bundles of fibers [polyester, kevlar, technora, carbon, or what ever that are] that are put in a laminated sheet material. Now in laminated material that is used for sails these bundles are not woven like plain weave. They are layered one over top of the other like making a sandwich. Now I am hungry. Ok laminate or laminated material, yeah yeah I hear you say I know what that means. In a laminate we start with a film we will say mylar, then we add a layer of uni-directional fiber bundles in the warp direction, then we add a layer of same in the fill direction then another layer of film. Then the whole thing runs through this really big machine and presto, Houston we have laminated sail material. Now during the layering process more layers of fiber bundles can be added in either the warp or fill directions or in an X-ply depending on what the end use will be. Now an important thing here is that the scrim in laminates is not woven they are layered. So scrim is all the stuff between the two outer films. Now poly tarp is not a laminate. There are no outer films making a sandwich construction. Poly tarp is a plain weave with either polyester fiber bundles or flat ribbons that is then coated with a polyethylene resin. It is much the same in basic contruction as is dacron sail cloth. But and I do say a very big "BUT" here other than the basic construction they are completely different in quality and materials used. The biggest difference is the yarn count per square inch, poly tarp will have a very low count, where dacron will have a very high count. Dacron is made of the very best yarns available and poly tarp is made of the cheapest stuff available. Geez my head hurts just writing this, it's too early in the morning for this stuff. :wink: Now I make sails out of dacron and laminates. I get my dacron from Challenge and most of my laminates from Dimension Polyant. I no longer use the lower cost laminates and I never used poly tarp. And boy can I get some really cool stuff, I mean really cool stuff. 8) Every time I get a sample of a new laminate sail cloth it's like Christmas. Why do I get so excited about this stuff, beats me I just think it's just too cool for some reason. Unfortunately most of the cool laminates are not for weekenders or gaff rigs But I am crazy enough to make a set of really cool mylar/kevlar optic 2 laminated sails for one. But my sanity can be questioned on a daily basis. Well are you now totaly confused? Later. Quote Link to comment Share on other sites More sharing options...
Tim Diebert Posted February 19, 2003 Report Share Posted February 19, 2003 Man......way to go PJ. It is nifty having an expert to fill in the blanks. So, you are saying then...that this high end poly stuff I am playing with has no direction then...to the scrim? There is no 'better' way to orient the sail when cutting? In other words....pathetic loosers like me ...that use poly...are doomed? That's a pile of typin for an early Wednesday morning Bub. Thanks for the info. Fascinating stuff. Quote Link to comment Share on other sites More sharing options...
Paul J Posted February 19, 2003 Report Share Posted February 19, 2003 Tim, First off I have no idea what poly you are going to use. It would be of great help if I did then I could answer that question. And if you can't afford dacron sails that's cool. No worries. But more info is what I need from you. Quote Link to comment Share on other sites More sharing options...
Tim Diebert Posted February 19, 2003 Report Share Posted February 19, 2003 ...you know, the shiney white kind. Quote Link to comment Share on other sites More sharing options...
Chris Potts Posted February 19, 2003 Report Share Posted February 19, 2003 So which direction should the scrim go in a properly made sail Quote Link to comment Share on other sites More sharing options...
Paul J Posted February 19, 2003 Report Share Posted February 19, 2003 Thanks Tim, That makes it so much clearer. Now if you don't mind I am going to go jump off the bridge and end it all now. Quote Link to comment Share on other sites More sharing options...
Paul J Posted February 19, 2003 Report Share Posted February 19, 2003 Chris, What material, they are all a little different and so are used for different things. One size does not fit all. I knew I should not have replied to Jo. It's all your fault Johannah it's all your fault. Now if know one minds I am going to go kill myself now. :shock: Quote Link to comment Share on other sites More sharing options...
Johannah Posted February 19, 2003 Author Report Share Posted February 19, 2003 Well I mind, you goof! Come back so we can ask more dumb questions. However foolish the question, your answers are always educational for the masses, even the colourful grousing. Quote Link to comment Share on other sites More sharing options...
Tim Diebert Posted February 19, 2003 Report Share Posted February 19, 2003 Don't do it PJ!!!! (have another beer instead) Quote Link to comment Share on other sites More sharing options...
Paul J Posted February 19, 2003 Report Share Posted February 19, 2003 Drats Foiled again! :roll: Quote Link to comment Share on other sites More sharing options...
Paul J Posted February 19, 2003 Report Share Posted February 19, 2003 Tim I would love to have another beer. But Craig drank the last one and has not bought anymore. Quote Link to comment Share on other sites More sharing options...
Tim Diebert Posted February 19, 2003 Report Share Posted February 19, 2003 DAMN that Craig! Does he not realize the seriousness of this situation!? Give me his phone number...and that Ed guy too! I'll tune these blokes up! :2gunfire: :shocked!: :scatter: Quote Link to comment Share on other sites More sharing options...
Craig Posted February 19, 2003 Report Share Posted February 19, 2003 Paul I told YOU to buy more!!! Why the hell is everything that goes wrong around here my fault. Now it has my dealings on this bourdinvolved through this government computer. You just watch that hoser Tim turn me in now!!! Aall this and we still don't know whtch way the scrim should go!!!!! Quote Link to comment Share on other sites More sharing options...
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