# Thread: A Seil in California

1. ## Re: A Seil in California

Photos:

The manager and supervisor inspect the new spruce.

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## Re: A Seil in California

You can do the calculation. The stiffness in some direction is proportional to the moment of inertia in that direction. The formulas on https://www.engineeringtoolbox.com/a...ia-d_1328.html show that for a rectangular cross-section, if you orient the thin direction across the direction of max force (not sure which that is for you) then the stiffness only goes down by 18%. Beware the stiffness in the thinner direction though which goes down to (0.82)^3 = 55% of its designed value.

3. ## Re: A Seil in California

Thanks Neil! I did not know that I could calculate stiffness this way. If anyone's interested, I found the formulas for an oval here:

https://en.wikipedia.org/wiki/List_o...oments_of_area

The calculations for a oval cross section work out the same as for a rectangle. Start with a circular cross section 60 mm in diameter. Diminish one axis by 10 mm. Stiffness in your thick axis is 83% of the original circle's. Stiffness in the thin axis is only 58% of original! I had a suspicion that things would get floppier but would not have guessed so much.

Which is too bad, because the yard is already shaping up in the shop.

My plan is to orient it so that it is thickest vertically to resist the loads of the downhaul and the mainsheet. I don't think it should experience too much loading fore-and-aft or athwartships because it's free to pivot about the mast. If it turns out to be too floppy, I'll cut it down to make a pole for running downwind and make a new yard.
Last edited by pez_leon; 01-10-2022 at 04:58 PM.

4. ## Re: A Seil in California

Originally Posted by pez_leon
Great to hear from all of you. Frank, your comments on the possible sail plans are interesting. Vivier includes both the boomless sail plan and the sail plan for the balanced main with boom. I haven't quite made up my mind but am leaning toward the boomless misainier. What I read about the misainier falls into two camps: people who haven't used it, who express trepidation about handling the large sail and moving the mainsheet in a jibe; and people who have used it, who laud its simplicity and performance. Anyway, thanks for sharing, and thanks for the link to your website. Your video is beautiful.
Rick and Thorne, thanks for the local welcome. I'll look into the local TSCA for sure.

James
I have an Ilur with a misainer rig. You have it basically correct. However, I underestimated the performance penalty for the loose footed main, and now I keep imagining converting to a balanced lug.

Downwind of course there is a penalty, but it is not just a matter of sail area. There is also the problem that you can't let the sheet out very much, or the peak of the yard will go forward of the beam, and then you will set up a rhythmic rolling motion that feels like its trying to capsize you. A balanced lug does not have this problem.

There is also a penalty upwind, which feels unfair. One of the advantages of the misainer is supposed to be an optimum sail shape when close hauled. And that's true—on the good tack. As long as the yard is clear of the mast, the sail is perfect. On the bad tack, I believe the misainer suffers more than the balanced lug. I used to sail a Caledonia Yawl with a balanced lug, and I don't remember there being such a difference in the two tacks. On the Ilur, because the lower part or the sail wraps around the mast, it presents a poor shape, with high drag. A boom on the bottom of the sail would hold the luff forward, and present a better leading edge.

The best justification for the misainer is if you like fishing. This was the original reason for the misainer. For setting gear, or working lines, its nice to have the boat as clear as possible. The lack of a boom is very nice while fishing because it keeps the boat clear.

5. ## Re: A Seil in California

Originally Posted by photocurio
I have an Ilur with a misainer rig. You have it basically correct. However, I underestimated the performance penalty for the loose footed main, and now I keep imagining converting to a balanced lug.
Interesting! Thanks for sharing this. Having already sewn the sail and built the yard, I'm in no position to change now- but I'll watch closely and report back, whenever the boat gets launched. I do wonder if the lack of a boom will be a nice feature with small kids aboard. We'll find out.

6. ## Re: A Seil in California

We finished shaping the yard. Not quite as straight as a ruled line, it sort of peaks up in the last meter or so, but I'm telling myself that this is a secret asset as it will deflect back to straight with the slightest load from the sail. Here is my boy taking it from 16 sided to round:

His interest in following my instructions started low and decreased. At some point I hit on the strategy of giving him 600 grit sandpaper (it being obviously six times better than 100 grit sandpaper) so that we no longer needed to argue about taking off too much wood. We got on great after that.
Last edited by pez_leon; 01-20-2022 at 04:53 PM.

7. ## Re: A Seil in California

On to the mast! I started hollowing each half in the middle of baby bedtime. That meant quiet, meaning no power tools, which was a nice excuse to pull out the plow plane.

Once the kid woke up I switched over to kerfing out the center with a circular saw:

I've got the hollows formed and am creating the mortise for the sheave now.

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## Re: A Seil in California

It is such a good idea to start with building sails, rudder, spars etc. for when you start with the hull, like I do, and she is finished, the other parts seem to take ages and it is easy to hurry up far to much.
I like your canvaswork, btw. I do canvas- en sailmaking workshops sometimes in winter, and I think especially canvaswork, is very much worthwile. Frank

9. ## Re: A Seil in California

Great to hear from you, Frank! It's nice to have some affirmation on my backwards construction sequence. The few people who know I started building a boat keep asking me when I launched her. All this work and nothing resembling a hull to show for it!

Mast work continued. Both halves are hollowed. A mortise for the sheeve is cut oversized, then brought down to dimension with hardwood cheeks.

Glue up with thickened epoxy and every clamp that could suit. I ended up throwing a few temporary screws in for good measure. The resulting glue line looks good.

Taking it down to octogonal. If you look closely at the facet on the top right, you'll see where it moves from smooth to rough. This shows the limit of my draw-knifing prowess; the rough bit has yet to see the plane.

A neighbor stopped by for a chat and fell in love with the spruce shavings that came off this project. She ended up taking a bag for some as-of-yet undetermined art project! At least I'm not the only one who likes a neat curl.
Last edited by pez_leon; 01-31-2022 at 03:14 PM.

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## Re: A Seil in California

Looks great! I envy you the natural light!

11. ## Re: A Seil in California

Very cool! I like that way of making a hollow mast. Seems like it could be scaled up larger than birdsmouth?

Do you hope to splash this summer?

Mike

12. ## Re: A Seil in California

Thanks for writing, Mike! Your Ilur build is a great resource. I nearly chose to make a birdsmouth mast after reading your description. I suppose this method of gluing up halves could be scaled up- maybe that's why it's detailed in Bud McIntosh's book, which focuses on keelboats.
A summer splash would be wildly optimistic. I'd love for it to happen but think that summer 2023 is more likely.
Long time readers will recall that I chose this design in part out of concern for capsize recovery. Here's a new video capsize test in flat conditions:

It's hard to generalize from this gentle water to the behavior of a boat in a real mess, but I like what I see.

Google translate offers this for an English version of the video's comments:

Arwen Marine (RAM) 2021 gathering at Lac du Der. Saturday morning free program: "I capsize my boat to see"... On the Swiss Seil "Aurore", Anne and Fabien decided to do it in raincoat, boots and self-inflating vest. Everything went well, like clockwork (obviously), and Fabien tells us that the self-inflating vest is not the total handicap that some decry, and he only (partially) deflated it when bailing out to increase freedom of movement. The water temperature (22°C) and the almost total absence of wind and chop make this series of tests by about twenty boats of little significance, because capsizing generally occurs due to severe conditions, but it has allowed many volunteers to see serious or trivial problems. In particular, I picked up two rudders, a few shoes, sponges, water bottles, etc. My fortune is almost made. More seriously, these tests showed that some participants did not succeed in righting their boat without assistance, nor in getting back on board alone despite the optimal conditions... These exceptions confirm the usefulness of this test, despite its apparent ease. We will renew it as much as possible during future RAMs, and will follow the progress of the failing crews. Lesson No. 1 is that it is imperative to release the GV halyard of the capsized boat so that it remains in the water when the boat is righted because its weight with that of the yard and the boom is enough to make capsize the righted boat again when coming on board, regardless of the effect of the wind. To be continued !

13. ## Re: A Seil in California

One score and three months ago, we brought forth, on this forum, a new thread, conceived in idle fantasy, and dedicated to the construction of a boat for sailing together. Now we are engaged in a great set of sub-projects. We are met in the backyard. We have come to erect a very temporary boat shed. It is altogether fitting and proper that we should do this.

We began with a slightly oversized vinyl billboard, purchased cheaply on the internet.

The world will little note, nor long remember what we said here, but each time we feel a drop of rain come through we will remember how you jumped and slid upon our shelter, child, yea even when I begged you to do otherwise.

All four sides need hemmed to fit the space and to house the PVC pipe run continually along the side. When I built the case for my sewing machine, I had no notion of its someday serving as a toy horse. That day is upon us!

The tarp is then affixed to a long 2x4 scarfed up from the rough-cut cedar I'm lucky to have a pile of. The whole assembly is swayed up to the level of an existing beam and supported at each end by a post.

A number of tie-downs later and there you have it: The Jackson Rancheria Casino Resort Lady Liberty \$15,000 Payout Memorial Boat Shed.

The top of the tarp is matte black. My wife came out a bit later and declared it "inoffensive" : target met. We cleared out the space underneath and are ready to build two linear footings to support the strongback, which will look like this:

Image: Duckworks/Ben Ullings

14. ## Re: A Seil in California

Back in the shop I've filled the weave and started fairing both the centerboard and the rudder.

The mast is just about done- I am hesitating to cut the tenon in its foot until I get the CNC-cut parts, which will include the mast step.

Those parts are due to arrive in mid June. Before then, I should rough out the rear transom. If I have extra time there's no end of work to do. It feels great to be back at it in earnest!

-James

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## Re: A Seil in California

Fantastic, more progress. Can't wait to see this in the water, maybe in the summer?

So that boat shed is very clever, but at this point should be more of a sun shade than any rain stopper. Matte black top sounds more like a solar oven, is it shaded enough to stay cool?

16. ## Re: A Seil in California

A summer launch would be fantastic, but I'm not setting any deadlines. I'm even doing my best to avoid expectations. They only cause trouble. I do hope to have it done before the rain makes working outdoors a dodgier proposition, but I built the shelter to handle some weather if things go long.
Good question on the black tarp! I would have picked white for exactly the reasons you mention, but left the decision to herself, who chose dark colors on aesthetic grounds. It turns out OK: the last few days were about as hot as it gets here in Richmond, and conditions under the tarp were quite comfortable. It's partially shaded and exceedingly well ventilated. I wouldn't want to try it in Fairfield! That 30 mile difference can easily equate to a 30 degree temperature change on a summer day.

James

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## Re: A Seil in California

Indeed, death by microclimate. There was a 130 acre wildfire 10 miles away over the weekend, in May!

My office is in Richmond, there's times I shivered in the fog after dressing for the weather in Fairfield. If you need an extra hand with a boat job someday send me a note.

-Rick

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## Re: A Seil in California

Great to see the progress on your build. Looks like your older apprentice has already found a makeshift moaning bench!

19. ## Re: A Seil in California

I wanted to build a traditional timber boat- still do - but chose glued plywood lapstrake for all kinds of functional reasons. I've been pleased by the amount of timber woodworking this build has nonetheless allowed.
Here's the rear transom rouged out:

Awaiting a quiet evening to cut the bevels:

20. ## Re: A Seil in California

A question for builders of CNC-cut Vivier kits: one must bevel one's own bulkheads, right? I haven't been able to tell if the CNC machine will bevel them, but the more I think about it the less likely it seems. I do note that the drawings include numbers (I think degrees) describing the bevel of each bulkhead at each strake. Any experience with this?

Thanks!

James

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## Re: A Seil in California

I've never seen a CNC cut Vivier kit,but knowing a bit about the cutting process,I would think bevelling would be unlikely.A 5 axis machine would easily produce the bevel if the files were in a 3D format.I can't convince myself that any designer selling plans/kits for home building would do that much work.I also doubt that the businesses that sell kits would have a 5 axis machine on hand.It is possible to remove an amount of the surplus material with a 3 axis machine if you put in the CAD time-in 3D-to create a ruled surface between the two faces of a bulkhead and then project a number of equispaced straight lines parallel to the faces of the bulkhead(s) as you can cut along each of the sections that result.The downside being that you have the machine running for a lot longer,which costs.In essence I doubt that there are huge benefits for something with the small bevels of the Seil.

22. ## Re: A Seil in California

Thanks for the reply, John - I am sure you are right. I'll pick up the kit on Friday and report definitively then.

For now: thumb cleats! These will attach to the top of the gunwales near the stern and will hook the main sheet return block. Two are needed - one for each tack.

23. ## Re: A Seil in California

I'll finish rounding but wait to countersink or drill flats until I have the real hardware on hand. I'm happy with how they came out, though next time I would wait until I have them split to drill the mounting holes. I slightly underestimated my bandsaw's kerf and as a result they are slightly out of center. I guess one is now port and the other starboard!

The transoms have their first coat of varnish and look wretched:

I am sanguine. In my experience cherry always absorbs finish so irregularly that film develops in some spots long before it does in others. It'll be dry enough to scuff sand and hit with a less-thinned coat this afternoon. We'll see how that comes out!

- James

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## Re: A Seil in California

It may be a small consolation but the transoms would have been just as blotchy if you had left the varnishing until the boat was complete.There might also be glue runs and other marks to remove.Was there any of the inner surface you could safely apply varnish to?

25. ## Re: A Seil in California

Great progress in the Jackson Rancheria Casino Resort Lady Liberty \$15,000 Payout Memorial Boat House

Three coats of varnish on the transoms:

The kit picked up. It turns out to be missing one sheet of plywood, but I have no doubt the sign shop will make good on it:

A tentative name has been agreed upon. On further discussion, we come to wonder if we shouldn't we have the blessing of the namesake. The manager drafts a request in the form of an illuminated letter. (Those circles in the water below the boat represent the moon jellies of Tomales bay. He loves them).

The jig is up:

So far I'm a big fan of the CNC kit!

- James

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## Re: A Seil in California

James, Great progress on your build. I love the boat shed. Your boys are such great helpers!

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## Re: A Seil in California

Hi James,

I am impressed by your level of skill. I built a Seil from a CNC cut kit done locally to me in the UK from Francois' plans. They were amazingly accurate. They were square cut but easy to round off with a router. I have a small garage to work in and the best thing I did was to put the jig on a moveable platformboat2.jpg
The jig was a perfect platform to glue the strakes together and then store in the hollow part.

28. ## Re: A Seil in California

Fantastic- a fellow builder of this boat! Thank you for the pictures and the ideas. I was just bemoaning my inability to store the glued strakes when you pointed out that the beam will serve. What excellent timing! If you have a chance, I'd love to hear more about your boat. Has she lived up to your expectations? Any surprises? Anything you'd build differently?
I too have been very impressed by the accuracy of the CNC parts. As I worked along the building jig, finding everything perfect to the millimeter, I must have internalized the idea that these were platonically ideal parts. I got to the end and found that the whole thing was 10 mm longer than expected and felt sincerely stumped. On reflection, 10 mm over 5,400 mm is an error of 0.1 % -obviously better than good enough, and far smaller than likely changes from heat and humidity expansion, to say nothing of my questionable joinery.
You are far too kind to compliment my skill on this. I am really just hacking through. I keep reminding myself to slow down and to appreciate what I'm learning. I recently read Russell Brown's Epoxy Basics, which ends with a reminder to take your time, prepare ahead as much as possible, and that "Enjoying your project is a good measurement of success". Exactly.

- James

29. ## Re: A Seil in California

Originally Posted by John Meachen
Was there any of the inner surface you could safely apply varnish to?
I opted not to worry about the inner face, both for want of time before I hope to mount the transoms on the jig and because I'm not entirely confident where I'll be applying glue. I thought about this decision today as I glued up the centerboard case:

None of those little splotches matter as it's all paint grade, but I wouldn't want them on anything destined for varnish.

- James

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## Re: A Seil in California

Hi James,

Well, I've got a lot to say about building the Seil, as my long suffering wife will confirm. I built the hull and then the components and as a previous poster suggested, by the time I got there I was running out of steam a little and v impatient to get on the water. Consequently, I bought oars and had the sail made for me. I decided to go for a balanced lug rig. The boom sits quite high and out of the way and she goes to windward surprisingly well. The key is cinching as hard as you can on the downhaul. Off the wind on a breezy day, she planes like a Laser. Just to catch up on a previous post you made about bevelling the bulkheads. I cramped the sole over the square edge of the bulkheads and that showed me the angle of bevel and it was consistent through all the strakes. I see you are constructing the centreboard case. I epoxied the inner faces before assembly and paid great attention to glueing them as I think this is the most vulnerable and inaccessible part. I haven't had an issue in four years of fairly vigorous coastal sailing. This is a link to a fairly silly vid of the first sail... Best wishes Chris

31. ## Re: A Seil in California

Originally Posted by pez_leon
As I worked along the building jig, finding everything perfect to the millimeter, I must have internalized the idea that these were platonically ideal parts. I got to the end and found that the whole thing was 10 mm longer than expected and felt sincerely stumped. On reflection, 10 mm over 5,400 mm is an error of 0.1 % -obviously better than good enough, and far smaller than likely changes from heat and humidity expansion, to say nothing of my questionable joinery.
Man, that brings back memories of me bugging Ross about why some of the sub dimensions in his plans didn't add up to the overall dimension. It turns out he designs in metric and converts to imperial to the nearest 16th of an inch. I couldn't see the forest for the trees that .0625" in a stitch and glue boat is nothing.

I'm enjoying watching your progress and especially like your memorial boat house!

32. ## Re: A Seil in California

Thanks, Chris, for the notes on the boat and for the charming video. I'm glad to hear you are happy with her! I am indeed currently constructing the case. I hear you loud and clear about the vulnerability and inaccessibility of this part. Today saw the wet out and filling of 10 oz fiberglass glass along the plywood sides. It was warm enough here to kick one used foam roller into an exothermic reaction, which I haven't seen before.

I hope to have this thing glued together tomorrow so that I can start mounting transoms, bulkheads, forms, and the centerboard case on the strong back. I like your idea of taking the transom bevels directly by using the sole as a batten. I did notice that one of the mylar patterns includes bevels, and I'm half tempted to them on the bench to those plans. I bet either way works.

In between filling the CB caseI glued doublers to the top of the bulkheads.

Here is (I think) another testament to the accuracy of the parts: some of those small plywood doublers don't sit exactly flush with the outside edges of the bulkheads but are instead proud or shy by a few mm. It's always the outside bulkhead, and always the offset you need to carry the bevel across this wider part of the bulkhead. So unless I'm mistaken these tiny parts are intentionally made a few mm larger or smaller than the piece they double to allow for a perfect bevel. I bet that would satisfy even the most precise metalworkers among us!

Hey Jeff - how's that transom mounted bassinet coming along? Gotta start 'em sailing young!

- James

33. ## Re: A Seil in California

Transoms, bulkheads, and forms are (mostly) attached to the strong back:

I have some advice for future builders: Don't establish the section (bulkhead) locations by measuring, as I did.
I lost at least an hour today to moving bulkheads around and trying to persuade the molds to fit the measured bulkhead location. I persuaded emphatically, so forcefully that I persuaded one of the fore-and-aft molds to break in half!

All this accomplished was to persuade me of my own foolishness. Oh well, lesson learned. At least it's not a lasting part of the boat. I think that some part of the problem was a very, very tight fit in the longest slot connecting two MDF pieces, and a larger problem was my having already fixed the bulkheads.

Obviously, don't do this. Instead, use the fore-and-aft sole molds to position all your bulkheads, then attach the bulkheads to the strong back wherever they fall. Once I did this they met perfectly the middle leaving the exact length of the centerboard case, which I'll slot in there tomorrow.

There is one bulkhead that just won't quite fit onto the two bolt holes that position it on the strong back. I can't tell why. I also can't tell if I'm fitting the sole molds and the bulkhead supports together quite right. Where two MDF pieces slot together at 90 degrees, the bottoms of the slots are not square but instead u-shaped (because the corners are rounded to the radius of the cutting bit). This effectively creates a mushy interference stop. You can make the fit tighter by pushing harder or tapping with a mallet to deform those radiused corners. As I write this, I suspect that the designer intends an easy press fit, but when I'm out there working on the molds it always seems to me they need to be tapped down harder into position, so that they sit tight against the strong back. This is the kind of thing I can only seem to learn by trial and error.

But man it feels good to make progress!

James
Last edited by pez_leon; 06-15-2022 at 10:00 PM.

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## Re: A Seil in California

Hi James..

Yes, first mould, then bulkheads. Once I got it into my head that the jig, parts and instructions are very accurate, the solution to any issue always lay with what I had done. I did ask Francois for some clarity a couple of times...he always replied promptly...and he urged me to work things out for myself (in a polite way!) and not to worry about deviating from the detail which makes for a unique boat. I thought this phase the most satisfying as quick progress is made. The best is turning the hull over and sitting in the shell, although my friend broke his finger in the process.

35. ## Re: A Seil in California

Thanks, Chris. The mystery of bulkhead 8 will have to wait for a few days until I return to the boat. I’m sure you’re right that any errors are mine and not the jig’s. It has been quite accurate.
I had been thinking of mentioning my success with pocket hole screws (not in pocket holes) for temporary alignment and clamping of parts for glue up. I inherited a bunch of these and while I’ve never used them for their intended use they’ve proven strong, and the flat heads limit marring. But no! I broke two on removal from the CB case before wising up and applying heat. Both broken screws came out with the homemade screw extractor:

As hoped the CB case slots right in.

Once I placed it got to wondering if I should glue it to the adjoining bulkheads (called out with the yellow arrow in that photo). The manual is mute on the subject, which tells me it’s probably a bad idea (Screws are to be added to the joint after turn over). If it is to be glued, it must be glued now before the sole goes down. Any advice from the crowd?
Last edited by pez_leon; 06-20-2022 at 07:31 PM.

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