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Author Yet Another Sail
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TAS
1961 Posts
Posted 09/03/2011, 7:53 am        Report    
Yeah Alright! So I want more, more more. I am thinking the Occums Razor has a Sail for Light Winds and one for Mid Range Winds now "She" (Lets face it if women can emasculate men a Razor can too. She Female Razor) should have another for special occasions such as Heavy Winds, now ain't that just like a woman? Never anough Dresses!!. Sail Makers all below is a pic of the last sail I have which the above BS should give you an idea of my intent to create a Speed Sail. Comments please and suggestions----------other than to "Jacksy it"/Cram it. At this point the markings aren't written in blood and if it is possible I wish to reuse this sail to get the best possible out of it. There is plenty of time untill I begin the cut. Ron
WA
5132 Posts
Posted 09/03/2011, 5:56 pm        Report    
thats still a good size sail. is it for the mini or the bigger yacht. Id be lloking for 1.5m on the foot, maybe 300mm on the head, and as it is a small sail , something with a fuller chord initially, so that you can get wound up in the first place
New Zealand
358 Posts
Posted 09/03/2011, 6:27 pm        Report    
I agree with Landyacht, but maybe only 250 at the top. It would be a good sail for both yachts. To get the right luff curve bend up the mast as hard as you dare with any old sail on. Then lay out a roll of building paper on it and draw the luff curve on to the paper to make a template for cutting the curve on the sail. The next smoking you'll be doing Ron is down that beach at 100k !
TAS
1961 Posts
Posted 09/03/2011, 7:38 pm        Report    
This sounds like what I is lookin' for. Seeing as the Masts are double tapered, inner to outer, I think I am being told that we need the sail to conform to the Mast to be used. This being the case then it would be a straight Cut and Shut using the top 4.5M of the Luff Pocket and Luff reinforcing? This is because Mast and sail were an item, as it were. Now that I have your input into this I will go about collecting further data and not use approximations/guesstimates. So keep feeding me your thoughts. Steve Walker Sails thinks that we apply too much pressure to the down haul on the Luff I was using 3:1 but have backed off to 1:1 but am feeling that in the guts would be more like it 2:1. He was surprised to see that it was automatically controlled by the Sheet, I can't tell if he was impressed or not. I will just have to pic his brain a little. Oh! A point of interest they are at least National Sail Makers and Designers and have our web pages so will keep a weather eye on our doings. Ron PS Paul it is for the Razor/Pac' Mag'.
New Zealand
358 Posts
Posted 10/03/2011, 9:04 am        Report    
I am a bit puzzled by your sheeting systems. Some of the photos of your yacht have it with rear sheeting and some with mid-sheeting. That skinny boom is probably ok for rear sheeting but no way will it handle mid-sheeting. Have you tried Mid-sheeting without the downhall in the front? You will need at least a 50mm dia boom with some internal stiffening. Triple pulleys top and bottom and a ratchet pulley at the tail. A landyacht sail needs heaps more leach tension than luff tension. About 2:1 in favor of leach. When fully sheeted in the leach should feel as tight as a drum skin all the way up. You can adjust the amount of draft (depth) with an adjustable outhall. Once you get up to speed you hall that in tight too. Picture below; I am powering up with outhall out.
TAS
1961 Posts
Posted 10/03/2011, 10:50 am        Report    
Clemco At the suggestion of Paul I moved the Sheeting to the rear of the Boom instead of the Central sheeting. That Boom is a Mast Top section. Given that my currant 2 sails have a 2mtr Foot would explain the Bow with Mid Sheeting. Believe me were they fishing poles I doubt any man could hold them given a fish big enough to Bend them. The amount of Carbon used in both my LY's would explain their light weight. Looking at your unit I would say your Sail Foot was aboout 1.5Mtr or a little less? Ron
New Zealand
358 Posts
Posted 11/03/2011, 12:49 pm        Report    
Good guess there Ron. It is just over 1400 eye to eye at the foot. That is my 4.0sqM sail. I dont use it much for course racing but its perfect for doing high speed runs in the stronger winds. I stack on heaps of wet sand into the yacht on those days so I can hold it down. I think sail makers could learn a lot by getting into a landyacht, and I don't mean a Blokart. They suffer from the same problem as the windsurfers; Not enough leach tension.
Posted 11/03/2011, 2:31 pm        Report    
Clemco said...
Then lay out a roll of building paper on it and draw the luff curve on to the paper to make a template for cutting the curve on the sail.
If you want to really do it properly then you cut the luff slightly differently to the mast curve -- there was a really good article on this that I came across years ago but can't find it now. Basically you make the lower area of luff curve 'bendier' than the mast, and the top section 'straighter'. This gives you fullness in the lower part of the sail and flattens out the top. This gives you more power down low, and if you think about leverage this means that you get more push for less tipping moment.
They suffer from the same problem as the windsurfers; Not enough leach tension.
If you're designing for one particular wind strength, and aiming to get the most possible push out of a sail without regard for gusts, Centre of Effort stability, and tipping moment, then you're right. However most sail designers recognise that in the real world, there are other factors to consider... there's more to the design than meets the eye in a windsurfer's sail. I guess you have to have sailed both types to understand the difference.
TAS
1961 Posts
Posted 11/03/2011, 2:32 pm        Report    
Clemco, If you don't mind what would your Gross Weight be when fully Rigged for sailing? The Razor comes in at 48KGs and I top it out to 148/150Kgs. In old money that is 330Lbs, so with the First/Old/Mid Range Sail it performs, to my way of thinking, Nicely and can corner hard on Bitumen before breaking out, this can be controlled easily by Counter Steering, on hard Sand it is a bit harder to control but none the less control it I can----------Depending on the turn tightness and Speed. It is good fun sliding down the beach sideways and finish up running backwards though. What you and the Lads come up with will help me to make a sound decision on Area, Shape etc. Ron
TAS
1961 Posts
Posted 11/03/2011, 4:01 pm        Report    
Ok! I took the Bit between My Teeth and did it Is this somewhere in the Ball Park of what is needed. 4.5 Height x 1.5 Foot x 300 Head? Just thoughts and what I think may be needed to move 150Kg/330Lbs. If I use soft Battens in the lower 2 pockets, Mast to Boom is empty, and Stiff ones in the top 3 should help to get fuller Cord low down?? Mid Boom Sheeting should also be good on such a small Foot? What say you? Ron
New Zealand
358 Posts
Posted 12/03/2011, 8:49 am        Report    
Nebbian; No I am not a windsurfer, but I have been sailing class 5 landyachts for over 20yrs. Yes, I do understand the need for the fold out head you guys need to keep balanced. I Also agree with what you say about more curve at the base of the luff to maintain some low down drive, but probably not that necessary if Ron is aiming at getting this sail to 100km/hr. I am assuming he will be sailing in 30+ knots to achieve that speed. Ron; My gross weight without ballast would be about 120kg. Over 10knt wind I start adding sand at a rate of about 15 to 20kg per 10knt of extra wind. So in 30knts I too would be at least 150kg gross. That sail is starting to look good. I dont think you need the top 400-500mm though. That top batten is still going to flap about and just create drag. Not sure what to suggest there.
WA
990 Posts
Posted 12/03/2011, 11:58 am        Report    
Ron if you are worried about the top flapping so much then remove the top batten. add a couple of layers to stiffen the top section above the second batten and maybe even cut it to a slight curve from that top stiffener to the top of the sail. This would allow you to put a bit more tension along the trailing edge of your sail
TAS
1961 Posts
Posted 12/03/2011, 12:18 pm        Report    
Clemco, What you are looking at in that Pic is around 300mm no more than that. I have just come back from Pegs Beach. I ran the new sail until it pulled the Mast down. My own Fault. However until that occurred I had some good study time, Looking up the Sail under 30kmh gusts the sail at the foot has a good Belly/Cord from foot to second batten (Remember Luff to Boom end is only a pocket) then the sail begins to Flatten out towards the top. It would seem that the outer half of the top Batten does invert a little though it does have some tension on it from the rest of the sail. I am picking most of that inversion can be cured. The Razor handles differently under that design, not as much tendency to break out under heavier gusts. She picked up speed quickly under either sail and the Gulls had trouble breaking away from us in the end they found it expedient to stay at the waters edge of make it there ASAP when we approached. I also enjoyed using a controlled two wheel Run or or 3, keeping the upwind wheel around 300to400mm of the sand. All in all I am Pleased with that sail for Sketchier Breezes. I also believe that as the Top of the Speed sail at 300mm, 1/3rd of the size of the Light wind sail will be efficient and have Zip in the way of Slack/Inversion. It is hard to get across what I am doing exactly on a forum so I can hope readers can read between the lines. Everyone is allowed to interject at any time and correct me if I appear to be blatantly wrong, only the best can come from that. Ron
New Zealand
358 Posts
Posted 12/03/2011, 1:09 pm        Report    
Test pilot 1 said...
Ron if you are worried about the top flapping so much then remove the top batten. add a couple of layers to stiffen the top section above the second batten and maybe even cut it to a slight curve from that top stiffener to the top of the sail. This would allow you to put a bit more tension along the trailing edge of your sail
Thats about what I was thinking too TP1. Nice sail Ron.
WA
5132 Posts
Posted 12/03/2011, 7:17 pm        Report    
Clemco said...
Test pilot 1 said...
Ron if you are worried about the top flapping so much then remove the top batten. add a couple of layers to stiffen the top section above the second batten and maybe even cut it to a slight curve from that top stiffener to the top of the sail. This would allow you to put a bit more tension along the trailing edge of your sail
Thats about what I was thinking too TP1. Nice sail Ron.
yup
TAS
1961 Posts
Posted 12/03/2011, 8:43 pm        Report    
Right Ho! Thanks lads. I wasn't too worried about the Heavy Wind Sail but if it will perform better then So Be It. I gather from those last comments that there isn't too much wrong with my thoughts regarding the cut and Shut. Other than to make one from scratch Jees! I'd have to save my pennies and do a lot of fast talking to get away with that one Like most married men I have an accountant/ Her what has the Pants Belt, to explain to Ron
TAS
1961 Posts
Posted 13/03/2011, 9:02 am        Report    
There have been a few things mentioned throughout this Thread that I shall have to elucidate ( How's that for a word(Elucidate, Forsooth!)) upon. Mentions; Leach Tightness. In the RAF Dynamic Sail Neal Pryde has added a string (Braided Dacron) down it's length. It is finished off by protruding from the Base of the Leach with a double Button ("MATRIX" Type Folder Fastener) This system allows the Leach String Tension to be adjusted for available conditions. This will be kept in mind for the New Cut and Shut. Sail Head Radius, I shall look very closely at the Radius-ed Sail Head and addition of Diagonal Batten. What sort off effect do you think will that have, Performance wise? Luff Curve, Keep in mind that there is only one shape for a Carbon WS Mast. Straight that is S-t-r-a-i-g-h-t. So any luff curve in the sail will decide the Mast Shape. Having said that note on the Recent Cup shape the top section of the Luff Pocket is only very gently curves. I think that maybe that curve needs adding too a little or a Leach Tension string needs adding? The Cat or The Razor? Never gave it much thought really but I think it probably could serve as a Light Wind Sail on Schrodinger's Cat and as a Heavy Wind Speed Sail on Occum's Razor. Only Time will tell on that one. OK! That about does it. Should I have missed something feel free to make note of it. Ron
Posted 13/03/2011, 11:50 am        Report    
nebbian said... If you want to really do it properly then you cut the luff slightly differently to the mast curve -- there was a really good article on this that I came across years ago but can't find it now.
Found it: http://www.sailrepair.co.uk/makingsail.htm
TAS
1961 Posts
Posted 13/03/2011, 1:22 pm        Report    
Neb's From my previous post. Luff Curve, Keep in mind that there is only one shape for a Carbon WS Mast. Straight that is S-t-r-a-i-g-h-t. So any luff curve in the sail will decide the Mast Shape. Having said that note on the Recent Cup shape the top section of the Luff Pocket is only very gently curves. I think that maybe that curve needs adding too a little or a Leach Tension string needs adding? I don't know what difference this will make to your thoughts. I like the Leach Tensioning String. It seems to work well on the RAF. I shall have a gander. Ron
Posted 13/03/2011, 2:15 pm        Report    
Nikrum said...
Luff Curve, Keep in mind that there is only one shape for a Carbon WS Mast. Straight that is S-t-r-a-i-g-h-t. So any luff curve in the sail will decide the Mast Shape.
This isn't true... by bend curve we mean the natural curve of the mast, when under load. Differing masts deflect differing amounts, and in different spots, and has nothing to do with sails. You measure it using a weight, some trestle tables, and tape measures. No sails are used at all. There are two measurements for this, the IMCS and the bend curve. Bend curve is probably the more important number to look at. Here is a selection of these two measurements, for a variety of masts: http://www.peterman.dk/masts-all-imcs01.htm If you have a sail that matches your mast, vs a sail that doesn't match your mast, then you can easily double your effective wind range. It makes a massive difference.
TAS
1961 Posts
Posted 13/03/2011, 4:42 pm        Report    
Whoa Nelly, DANGER! Warning! Taiho! Stop! Now we can all start again. I forgot the other sail was not the same as the Last Cut And sorry about this Lads, though I suppose all of the above still applies?? Ron
TAS
1961 Posts
Posted 13/03/2011, 8:58 pm        Report    
I had a look at that sight in t UK Sail Repairer. In answer to a couple of Q's this is what he had to say; Hi Ron What you are proposing would work, but you could just about make yourself a new sail in the same time. If you are going to cut down a large windsurf sail you are doing the right thing using the back half as it has less seam shape. You would cut more curve into the luff curve in the top half to tension up to top of the leech. The downside if using a old windsurf sail is that sail like that are made of thein 100 or 125 mic monofilm and if its old it will have seen quite a bit of uv light which breaks down the monofilm. Weight is less important for you and a stiffer thicker film would be better. It is not something many people think about but in high speed applications the hardness of the cloth makes a difference, the harder (stiffer) it is the more wing like it will be and the more efficient. I suppose it all depends on how high performance you want to go. Since the top of your sails are just about flat you could make a sail out of just 3 pieces of monofilm. What do you think? Cheers John That 3 pieces of Mono sounds interesting but I don't think I could afford to go there. However I will look at putting a little more bend in the mast top. When I'm done it may be possible that this Speed Sail will Shake Me Down Ron PS. John if you spot this post. This sail was not very old at all. From the look of the Damage I would say that the Downhaul System was just a tad on the heavy side. The owner Tore the Downhaul loop in half. It also looks like the Mast bust and went through the Luff Pocket. It also has a little tear at the foot, like it was blown onto sharp rocks. What I want is pretty much like new.
TAS
1961 Posts
Posted 05/04/2011, 1:08 pm        Report    
Ok Lads, This is the way I think I should go.. Pic 1 You will notice I have pulled a Working Curve in to the mast and also dropped a line to indicate sail profile.. The remainder, that curve traced onto the Template Paul suggests for the Mast types that are in general use. Just looking at that Curve I think I may have to take about 20mm out of the top 500mm of the Luff. What say the experienced Choppers All advice is taken into account Thanks Ron
WA
5132 Posts
Posted 05/04/2011, 8:45 pm        Report    
stick with the template curve, otherwise you,ll end up with a really flat sailwith the battens doing nothing
New Zealand
358 Posts
Posted 06/04/2011, 9:01 am        Report    
Can you set the boom a bit higher at the rear so you can sheet it in more. I am sure you can bend that mast a lot more than what you have to fit Paul's template. I am always amazed how much harder I can sheet in when I am actually sailing compared to when the yacht is stationary. I think it's a combination of adrenalin and the shock factor of the yacht getting bounced around.
TAS
1961 Posts
Posted 06/04/2011, 12:03 pm        Report    
In answer to both threads, Yes it will follow Paul's Template, the Boom Clew End can be raised a Tad more, I may have to nip a tad from the top 500 to 700mm of the Luff to get a little more tension on the upper Leach/Top Batten to Mast Should I do that will that deviation do that Paul? I will go Redo that Curve Test again. Ron
TAS
1961 Posts
Posted 06/04/2011, 1:47 pm        Report    
Right Paul and Clemco, This pic shows the Mast with it's inner Curve (The Mast is Double Tapered) matching the Template which to all intents and purposes allows a line dropped Perpendicular down from the Leach Elbow to drop almost through the Axle. I forgot to upload it I don't think I cleared up my worries won the last Sail re-cut. Given that the Mast is Carbon Fiber as opposed to varying thicknesses of Ali Tube and that it has an even taper etc won't that make a difference to the curve required?? At this stage I don't understand what Steve wants to do with the curve but I need to understand both parties ideas. Ron PS; I won't allow any radical changes.
WA
5132 Posts
Posted 06/04/2011, 7:52 pm        Report    
Clemco said...
Can you set the boom a bit higher at the rear so you can sheet it in more. I am sure you can bend that mast a lot more than what you have to fit Paul's template. I am always amazed how much harder I can sheet in when I am actually sailing compared to when the yacht is stationary. I think it's a combination of adrenalin and the shock factor of the yacht getting bounced around.
yup. and leave the curve alone
TAS
1961 Posts
Posted 06/04/2011, 9:46 pm        Report    
Thanks Paul/Pal I managed to edit my last post. Now you have a pic to look at. Ron
WA
5132 Posts
Posted 07/04/2011, 9:00 pm        Report    
so , did you cut to the template curve or are you still faffing around( hows that for a word, faffing) and not biting the bullet. what you need to do is pick which advisor to follow( rather than them all) and just get on with it, you can always recut afterwards to tweek it. I often recut a luff 2-3 times to get it really sweet. as you are RE cutting a worn out windsurfer sail, its rare to get a perfect result, thats why its an amateur art rather than a science. and also why you save the sailmaker for making new sails also keep in mind that you could destroy it after a few sails, so this should affect how much time and money you spend on each sail
TAS
1961 Posts
Posted 07/04/2011, 9:29 pm        Report    
Well I guess there is that in it too but my little Elna doesn't like Mylar. Come to think of it it plays up if it isn't plain old Cotton No I've not started the re-cut yet. I have to keep the Boss happy too you know, Lawns to Mow, Trailer Loads to take to the Waste Station etc but I will get there shortly. Tomorrow looks like it may be good for a shot at Pegg's Beach. I have bought a new Waterproof Helmet Cam so when it arrives I will post more Footage.. Actually This sail, in the main, is in fairly good nick and any damage is outside the area that will be used. Ron
 
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