If you make it to NACA006 it will be 1/2 as thick and fit the centrecase.
If you make it to NACA006 it will be 1/2 as thick and fit the centrecase.
That's my conclusion as well. Of course, being a non-"type A" sailor who has never sailed with a fat NACA foil, you'd be wise to take my comments with a pillar of salt.
But it's easy to round off the leading edge and taper the back of a thin foil as John says, which will provide far superior performance compared to a flat board.
Tom
The advice I have seen and followed regarding NACA profiles on thin boards is to use the profile for a thicker foil in order to leave enough material to preserve the board's strength, and just leave it flat where it is thinner than the NACA profile. Flat sided boards with leading and trailing edges shaped to NACA profiles are evidently pretty close in performance to boards with the full profile they are based on.
Because of the flat sides they are pretty easy to make using templates and sanding jigs as shown here: https://www.storerboatplans.com/foil...ormance-by-10/
This +1
basically keep the board as drawn and tart it up a bit with some nice shapes
The best thing about spending a bit of time on this is that the not only does the boat handle a bit better and maybe it's a bit faster, but the slow speed maneuvering characteristics are significantly improved. Everyone shapes for speed, but I see the most benefit at slower speeds in tight places. This is nice for docking, ghosting creeks, and other such things.
I think I remember reading somewhere on the forum that there are low hanging gains to be made just from shaping the leading edge to a parabolic rather than round shape, and tapering the trailing edge.
I've been intensely busy with everything except the boat. On the few days I've had a chance to get out to the shop, air quality has been so bad that I've hesitated to linger outside (or in my open air workspace). Some days this can all add up to a lot of pent-up pressure and a real desire for manual, tactile work. Thankfully there's parts of this project that can be done in the house.
My sail kit from Sailrite showed up last Friday.
I spent a couple of very happy hours this weekend working on patch assemblies. At first I made the mistake of trying to work while my kids were awake. If you add in the cats this made for a crew of five rascals and scallywags, all of whom had different approaches to, and opinions on, the project. Is the thread for eating, or for tying gordian knots? Should we crush tomatoes into the dacron, or just grapes, and wouldn't this be a great place to cough up a hairball? No one could agree on what to do next. I'd like to report that the ragtag bunch of misfits finally pulled together to win the championship and finish the sail. I cannot. The best solution has been to save the project for nights after kid bedtime
I'm very pleased with the kit from sailrite. Everything they shipped looks top notch, and it really is hard to mess up the overall assembly. I'm less pleased with my stitching. I'm assured that from any distance it looks just fine; personally I can't help but notice all the errors. But I'm not too bent out of shape. In a couple years I'll look at the wild zags and drunken, unfair lines of thread and remember happy nights stuck inside with sleeping kids and wretchedly unhelpful cats.
James
James-
I really enjoy and empathize with your posts. Up here in Oregon we had about two weeks of off the charts hazardous air. Add cats and small children into the mix and yes, that is sure to be slow down to work. I learned to sew sails about eight years ago when a friend and former pro sailmaker helped me out. Once a week we'd transform my living room into a sail loft. Out went the rug, chairs, and couch. I stopped him from putting tacks into my fir floor to hold materials in place. Instead, my kids (who were in late elementary school) were conscripted to help, but were kept away from The Beast. That being a commercial size sewing machine that I was warned would comfortably sew through sail cloth, plywood, and fingers.
Sewing was one of my favorite parts.
And no fingers or children were physically harmed in the process.
Good luck.
-Bruce
Tales from the land and sea: http://terrapintales.wordpress.com/
Boy can I relate! I have been working on my mast which is too big to do anywhere but outside, and the bad smoke days were just lost as far as getting anything done -- not to mention the toll on keeping the kids cooped up inside.
Hi James,
I believe you can make NACA 00XX foils in any thickness you want. The 0012 and 0009 foils are just pre-calculated thicknesses. I'm not an expert by any means, that's just the conclusion I came to after a bit of reading.
Use this calculator with camber set to 0%
http://airfoiltools.com/airfoil/naca4digit
If you're worried about strength you can make the boards out of laminated solid wood instead of plywood. You can also cut a groove on either side of the board and lay in unidirectional carbon fiber strands, see this article for more: https://www.epoxyworks.com/index.php...-centerboards/
Richard Woods has a reputation for designing fast boats and he specifies 5% thick daggerboards on his strider catamaran, so there are high performance boats with thin foils. See here for a strider going fast: https://www.youtube.com/watch?v=KNyyHo-O-xs
This looks like a great project and I'm looking forward to seeing your progress!
Nick
Edit: When you calculate the foil make it longer than the finished board so the trailing edge is 2-3mm thick and squared off, not razor sharp and fragile.
Last edited by seasnail; 10-07-2020 at 08:00 PM.
Thanks for all this advice on the boards. I've got the blanks just about complete (laminated solid ash) and will probably use the NACA 0012 profile with flats, as described by cracked lid. I have been planning to lay paracord into a groove around the permiter of the board to strengthen the leading and trailing edges. I think it'll be sufficient for my needs, but then again, there's something satisfying about even just saying "unidirectional carbon fiber".
I really appreciate all your advice.
You're building a BB14, right? How's the project coming? I was wondering if you got the Sitka Spruce for your spars from McBeath, and how you found working with it. I'm still waffling between shelling out for sitka or just cutting my mast staves from clear lengths of DF 2x12s. I should decide soon: the DF 2x12s down at the lumber yard are pretty green, and I'd want them to have plenty of time to dry.
What are your plans for sails? If you're interested in making your own, you'd be welcome to borrow my spur grommet and eyelet dies.
This picture brought back some old memories of my cats, (Alice the black cat and Chip the tabby) coming to supervise my sailmaking. Still have fur stuck in the seams, that basting tape is tenacious.
Steve
If you would have a good boat, be a good guy when you build her - honest, careful, patient, strong.
H.A. Calahan
The project is well along, I am about done with spars and the next thing is to flip the boat and fair and paint the outside. Then blades, ballast keel and rigging.
I got the Sitka from MacBeath, yes. I don't have a basis of comparison, I haven't worked with it before, but it's been a pleasure to work with. There were few hidden blemishes that I had to deal with, the grain is tight and straight, no complaints. The Herreshoff design calls for a quite light hollow mast so I felt it was worth the expense to use sitka. Is Seil's mast hollow?
Thanks for the offer on the sailmaking stuff, I had sails made and received them recently, which has added to my impetus to get the boat finished!
No progress on the Seil! Why? Because it was too good of a weekend for sailing. I got out for an overnght on my fiberglass trailer sailer on new-to-me Spicer Meadows Reservoir. Let's call it reconnaissance for future sail and oar trips.
We put in at the boat ramp on the west end of the lake just as the afternoon up-canyon wind came in. This late in the season, the water level was about 40' below capacity, leaving a starkly delineated bathtub ring. Above the mark - firs and pines, glaucous shrubs, and dark lichen. Below- bleached white granite, dead tree roots, clear water, and our little boat.
Five miles of increasingly speedy downwind sailing brought us to the first passable boat-shaped nook with enough shelter to pull up and rest for lunch - somewhere around the "mile 10" marker on that map. Normally, we'd eat gourmet, but on account of our 2020 firestorm the national forest has categorically banned any heat source. Without the incentive of hot meals we got lazy, omitting to pack, among other things, any kind of mug, bowl, pot, or spoon. So we ate crackers, apples, and cold Folgers coffee reconstituted in bad beer. Beer, because I forgot all my extra water bottles and was now feeling in too much of a tearing hurry to wait 30 minutes for my iodine water purifier.
The rush to get back on the water was possibly the only smart thing about our day so far. We were about as trapped as my boat can get, with the nearest soft landing miles back the way we came and right into the eye of the growing wind. We packed on layers of synthetic clothes, cleared the boat for a capsize, tied in a reef, exchanged our wills, and launched.
Then there were two hours of fantastic tricky sailing without a moment to think of anything else. The wind was strong and right in our teeth except for the rare moment when it would back all the way around the clock to utterly foul a tack. Every possible course ran through, behind, and just over dead trees and boulders. The canyon was so narrow we'd hardly have time to work up speed between tacks, and because the reservoir was so far below its high water line, the entire coast was hard granite walls and dead roots.
This was perhaps not the best way to sell a greenhorn on mountain sailing. To his great credit my crew loved it. He was unfazed by chop pouring over the deck and into his lap; he was unfazed by a few near-knockdowns scooping dozens of gallons of water over the lee rail; he was unfazed when my task-loaded brain failed to clearly tell him what to do with the suddenly backwinded jib and our head was pushed around to leave us sailing at tearing speed downwind, missing the rocky coast by mere inches. We were drinking joy from a fire hose. But the wind was only building: no amount of hiking out kept her even near level; and in the worst gusts she'd round up even with the main played all the way out and the tiller hard over. We hadn't said a word to each other for maybe an hour when we saw a little boat-shaped cove, possibly the only safe harbor for miles. A significant look, a nod, and a final tack brought us into the lee of a cliff with just enough time to drop the main as the bow kissed into the only soft sand we saw all day. It didn't matter that we were still in the narrows and increasingly wind bound- we were safe ashore and ready to wait it out.
The cove was made by some kind of cut in the canyon wall, likely an old fire road. We followed it straight up into a marvelous campsite. I liked the way the wind knocked my hat off as I was pitching my tent- just another reason to feel glad to be off the water. We took an afternoon stroll up to the top of a local hill for a view of our day's sailing.
The view from our hike. Note the boat down there!
The next morning I awoke to exactly the conditions we had hoped for: a soft, down-canyon breeze blowing us back home. The predictability of this mountain weather made it no less welcome. But where was the crew? Up early, and off somewhere out of contact, perhaps on some lubberly walk. I scurried about packing and considered hoisting a blue shirt to the masthead. He showed up when he was good and ready. Thankfully the wind still served when we launched, at least long enough to carry us through the narrows and into the reservoir proper. We sailed along with one hand for breakfast crackers and another for cold instant coffee, leaving the boat to steer herself, marveling at how easily we made our mileage compared to the previous afternoon. When the breeze died fully we struck sails, brought out the trolling motor, and hustled home.
Last edited by pez_leon; 10-12-2020 at 05:56 PM.
The excitement should end there. But wait! There's more! I would argue that the speed at which I took a tight, unbanked downhill turn on that mountain road was entirely reasonable, well below any kind of danger. My boat trailer would disagree. It jumped off the ball and fell over sideways. The boat skidded along on its side and now has road rash to show for it.
Everything was easy to right and to re-attach, and now I have an opportunity to learn more about fiberglassing before I sheathe my rudder and centerboard. I wonder if the great minds on this forum would want to weigh in on what happened. I haven't heard of a trailer tipping over before, and I'm not sure how it managed to get off the ball. I suspect something is either defective or misadjusted with the coupling on the trailer side. The cam lever was still down (and padlocked) after the trailer fell over. So how did it get off the ball? I clearly need to do something differently.
Ouch! Fun until that happened...
Obvious dumb question: Is the ball size correct for the coupler? More questions: Did you see if the trailer uncoupling caused the fall, or did the twisting fall yank the coupler off? Did the chains catch it, or did the coupler strike pavement?
-Rick
Great trip! Sorry about the trailer...
I really enjoy your write-ups, by the way. Thanks,
Tom
Rick, thanks for the ideas. The ball and the trailer match. You can bet I spent a while staring at the engraving on the coupler and the ball, just to confirm. The coupler did include some language about "adjusting to the ball", so I checked the nut at the bottom of the cam lever. I turned it a bit (less than a full turn) and it did feel more snug - but not very different. I spent the rest of the drive worrying I'd made it too tight.
I don't have a great sense of sequence at the time of the crash. My suspicion is that the twisting fall yanked the coupler off the ball, but I can't confirm. The trailer chains were not crossed underneath but instead running in parallel, so they did not catch the coupler. Thanks to your question, I now know why I should cross them!
I always remember - don't cross the streams, but DO cross the chains! "It would be bad..."
Perfect mnemonic, Rick. I myself have been reflecting on this movie clip:
Hey Pez! What a cool project. I can't wait to see the build progress. I've been eyeing Seil for a while. Vivier's eye is really something.
I'm also in the bay area. After building a 16' Dierking Wa'apa and a partnership in a J/92 a sail and oar boat feels like the next step for me; something for
I have a little experience with foils and lug rigs I wanted to share.
I converted Gary's Wa'apa files into CNC cutable files. I cut the leeboard and rudder with a NACA profile that had the chord length that Gary drew, but with a thickness that came out to 1.5" so that I could cut each half from 3/4" plywood on the CNC without having to flip any parts. Is a NACA section board better than a flat board with a rounded leading edge and a sharp trailing edge? Probably, but I don't know how much more lift, and how much less drag there would be. All I know is that my lug rigged stone age canoe claws to windward like a beast. You can look at the surface piercing foils working on my boat and they look slippery.
I used a CLC 60 sq.ft. lug sail and build the spars to their spec. My canoe has hiking seats so my butt is at least 18" outboard of the gunwale, and I am not a small person, so there was a lot more righting moment than the little dinghies that the sail was designed for. The mast bent like a fishing rod with a tuna on the hook. I ended up adding a braided carbon tube to the wooden mast and my sail control was wildly improved. I'm a big fan of the goat island skiff style of rigging. My new 4:1 outhaul can get that thing as flat as you want.
Standing lugs with a sprit boom feel SUPER interesting. But my Seil would probably have the balanced lug righ with lazy jacks so that dropping the sail will be less of a yard sail than my current set up.
I'm really looking forward to seeing your progress!
Chris
This project has barely started and already we're taking detours.
Harry Bryan's article on spar gauges in the most recent edition of WB got me thinking about my frustrations with the gauge I'd used on my oars. I liked the more complicated gauge he described, and I liked the idea of making metal bits that I would have thought out of the reach of my workshop. I'm pleased with the result and looking forward to using it on my mast and yard.
It marks well:
And passed inspection by the supervisor:
James
Chris, I'd LOVE to see your outrigger sometime. I bought Dierking's book and thought hard about building a Taman'u. Warmer water, fewer kids, who knows what could have happened. Do you ever sail out of the east bay?
Clever. I'm going to stick with the spec'd thickness of the board (got the blanks just about made up) out of respect for the design and fear of cascading, unplanned changes. I'm also looking forward to shaping the board by hand. I once made a rudder from a table of offsets and, at the risk of sounding totally wonky, it was a nearly mystical experience. I'm not a great drafter, craftsman, or technician; yet somehow, I got to watch my hands turn a bunch of numbers in an ASCII chart into an exquisitely and precisely shaped wing. I'm looking forward to some good winter nights in the shop.
Nice gauge! It is often serendipitous what turns up in WoodenBoat magazine, but in my case the latest issue arrived on the day I began varnishing my spars. I wish it had been in the prior issue, I could have made one of those and avoided the frustration of using the usual simpler spar gauge!
Yowza! I need to up my game with my spar gauge.
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I have added another sail maker to the team. Somehow, the pace of work has not increased much.
He recently stopped calling the project "dada's sailboat" in favor of "our sailboat". So long as it remains a collective project he can set any pace he likes.
A question on leather: the kit shipped with 2-3 oz pearl gray cowhide to dress the corners. I'm sure this would work perfectly well, but it won't match the color scheme of the boat. I have some fairly lightweight vegetable tanned leather that I'd like to use. My only concern is that this leather might leach tannins when it gets wet, and that those tannins may stain the sail.
Any advice?
James
Dang that kid has some energyYou ought to make him the motor for your new craft. And good on you for keeping going with all the extra help!
I don't have experience with tanning, but I have both gray and dark leather on my boat. Both have darkened some over the years- especially after years of tallow and rubbing on oarlocks and spars... I'd be inclined to just use the leather as is. Maybe after a while you won't notice it?
-Bruce
Tales from the land and sea: http://terrapintales.wordpress.com/
Marking
Cutting
And dressing (half done)
I went with my own leather, not the kit's. If it stains the sail I will have no one to blame except all of you (except Bruce).
Now sewing in rings. Very satisfying work.
I'm looking down the next few days of work to completing this sail. To store it cleanly I might as well make its bag next. When the boat's finished I'd like store the sail attached to the yard under the boat cover.
Any advice on the right material for a sail bag? I suppose the ideal fabric would be very breathable so as to tolerate putting the sail away damp. On the other hand, when camping aboard on a rainy night, I'll be sharing space with the sail. It might be nice just to seal the whole thing in a waterproof bag to keep my quarters dry. The kits I've seen (sailrite) supply 400 D Nylon, which I think is fairly breathable.
There's another question there: I never put my current sail away damp. Do you hardened sail-and-oar types really just leave it all in the boat between trips? Sure would save some time...
James
When I got my (very nice) lugsail from Dabbler Sails, it included a canvas bag long enough to take the sail and yard. It looks like there's some kind of coating on the inside of the canvas, probably at least water-resistant? Not sure how breathable it is.
Between trips, I always make sure to dry my sail in the sun if it was at all damp at the end of the trip/day, then I do leave it rolled up in the sail bag stowed inside the boat. The boat itself stays under a cheap boat cover for a power boat (i.e. way too wide, especially at the transom) that I prop up with tent poles. It keeps the boat 80-90% dry in rains, so some bailing is usually needed. But that's just the bilge--the sail stays dry up on the thwarts, more or less. If it's a real heavy rain then I'll take the sail out again to dry it.
During a trip I don't worry much. I often just leave it stowed in the boat, not in the bag, overnight. I know it'll dry the next day when I sail again. Or if I'm in camp for more than one day, I might spread it out to dry ashore.
Tom
I agree with many of the things Tom said. I have tried to put the sails in bags on a cruise and it just isn't worth it. I just furl the sail and lash it to the spars.
As needed, I do dry the sails after each trip and store them in my basement- off the ground away from dampness and mice. My sails don't soak up water, but they don't dry out furled either.
Sail bags are pretty subjective. Here's my experience with different materials:
* Waterproof plastic "canvas". Pro: Modest in price, super durable and water won't get in it. Con: Water won't get out either. Not super flexible for sewing.
* Sunbrella. Pro: Highly breathable, UV resistant, fairly water resistant. Con: it is a little scratchy and can wear the varnish or paint off of hard surfaces if you leave it in your boat while trailering (don't ask how I know this) Need a big machine to sew this stuff.
* Ripstop Nylon. Pro: Slippery, easy to get on and off the sails. Easy to sew. Con: Not generally water resistant (though you can buy that kind).
* Canvas. Pro: Durable, salty looking, repels a little water. Provides a little padding for spars. (Waxed duck repels a lot of water.) Con: Eventually soaks up water and is kind of unmanageable until it dries. Need big machine to sew.
Let us know what you decide.
-Bruce
Tales from the land and sea: http://terrapintales.wordpress.com/
2020-08-08 16.33.07.jpg
The owner of this Le Seil wanted to take her to Venice for the VogaLonga and also the Vela Longa on the lagoon. The local sailing fishermen paint the sails so their wifes know where they are and they, the le Seil owners, wanted to blend in. They asked me, I made the sail in white terylene, what paint to use and this is the result. They also had the builder, Ben Ullings, make a Forcola to row facing forward as it is very Italian and told me it is also nice here in The Netherlands: You can see the fishes when standing up and facing forward. It is also a pretty good sailor, shown here with family onboard during 'The noorder Raid', on the Lauwersmeer. Frank
www.oarandsail.nl
I made a cover for my boat with Bisonyl, as it is called here, a coarse terylene fabric covered in (I think) PVA, a very strong heavy material that also used to cover the open sides of lorries. If I did not have a sewing machine with a walking foot I might have used a Sunbrella type of cloth. I found that my customers almost never use the sailbag that I made for new sails, I make a long bag now so they can put in the sail, bent to the yard and boom. Since a few years I use 'Stormlite 210, sailcloth for Code Zero sails or very big gennakers. I made a 225 m2 gennaker with the stuff for a big steel Zeetjalk and bought a lot of seconds'' stuff and had plenty left.
When I came back from The Morbihan 3 years ago I did not rinse my sails with fresh water and although the whole rig was hanging fro the roof in my garage it mildewed and i cannot wash off the small black spots on the sail.DSC_0004.jpg