# CS15 with a lug yawl rig

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Steve:

For help in planning the rig, etc, I got a lot of good ideas from this book:

When it came time to build the sail, I contacted Todd and he not only built me a sail, but designed it to the center of balance and mast position of the Spindrift 10, so is pretty much a one of deal......probably why it works as well as it does. He also gave me some specs for the boom design, which came out to be remarkably similar to the stock spindrift boom. So much so, it would be easy to use either. The advantage of the boom jaws is the elimination of the gooseneck, so you can either slip the mast through the jaws, or use a bit larger line for the parrel beads and tie in a quick stopper knot each time you rigged if you want to leave the mast in place. This can all be done on the water and is relatively easy to rig.

On the gaff and halyard design, for that, I borrowed heavily from Storer's balanced lug rig. The way he shows to rig it works really well. Again, as for the advantages, the sail can reefed, but can also be hoisted and dowsed while on the water. To find that it also performs well was a huge plus. Looking at a lug sail, you would not expect it to perform all that well, but somehow it does.

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Since Ed mentioned my boat in this thread I thought I would reply.

Ed said: "There is a CS20 in Denver with a cat ketch, lug rig. I noticed he really had to upgrade the masts to make it work."

As it turns out the masts for my balanced lug rig are the same size as the two bottom sections for the stock rig. 3" and 2 1/2 " in diameter. Since they are 6 feet shorter and have no sail track they are light and easy to step so I took off my mast stepper helpers. I think the main reason I did the balanced lug rig was just 'cause it seemed like a fun project. Since I am no great shakes of a sailor I don't worry much about how the rig performs compared to the standard rig. I have not had the courage to sail with full sail in much wind. I look forward to reports on how the CS15 lug yawl perform since I would like to go from a CS20 and S10 to a CS15

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For the CS 15, I have adopted a lug yawl rig that Clint Chase designed for the Goat Island Skiff.   The GIS and CS 15 are about the same length (two plywoods) with centerboards in nearly the same place, but I did the center of effort math anyways, just to be sure.

Clint's plans can be found at http://www.clintchaseboatbuilder.blogspot.com/p/articles.html.

Bob

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Oh Boy!   CS-15 hull #152 is 3D.

I built the cradle on the trailer so I can roll out of the cramped garage space when the weather is nice, and because I needed to put the trailer someplace.

Unfolding went smoothly.  Much less creaking and popping than in Alan's videos.  I measured and tied a rope loop that fit around the temp. center frame with a little slack.  That did a good job of keeping things together.   One of the bottom panels sort of buckled in instead of bowing out, but a weight put that right. You can just see the weight in the 2nd picture.  It's really satisfying to see that boat shape appear!

Cheers,

Bob

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HI All,

Inwales are in, and I spot welded the chines, transom and keel seams.   Near the transom, it took a lot of force to pull the bottom panels together, but I got the nice upturn in the keel line.  I just hope it stays.  I used a couple of fiberglass tapes to beef up the tack welds in that section.

It's tough to reach the center line over the gunwales, even for a tall guy.   I came up with this spatula-like tool, and it worked great for the spot welding.  I put my thickened epoxy on a scrap, scraped off beads of epoxy on the tip of the spatula, and smeared/squeezed them in the crack.  The business end is half of a rubber scraper.  Cured epoxy pops right off.

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During the construction of CS20 #103 (Dawn Patrol) there was a photo posted of Alan solving the "How do I reach the centerline?" question.  I think he did the Wallendas proud, but I don't have a copy of the photo to post.  Hopefully one of the Stewarts will share a link.

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One of the things I've found useful when trying to reach stuff in the boat is a movable cradle. On the CS-17 I built I made a cradle that could be rotated from square on the floor to about 45 degrees. It dipped the hull to each side as required, so I could reach in, while standing next to it and get at the seams. In this case it was little more than a few plywood cradles, matching the deadrise, but instead of legs in the traditional sense, I cut the bottom of the plywood at an angle and used some premeasured blocks to return the "teeter totter" cradle to it's square to the floor orientation. I did the same thing when the boat was upside down, except I just used some legs, again angled at about 45 degrees, so the boat could be rolled from one side to the other.

This picture shows the boat being rolled over from inverted and the upside down version I just described is still in place. If you look close, you'll see a slot in the forward V legs, which fit into a wheeled dolly, so I could move the boat around in the shop. The aft legs had a flat spot, so when rolling from one side to upright, it would stop and not just keep rolling over to the other side. Simple, effective and lets you get it stuff easier.

....

...

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Hi all,

Here's an update on my build with a few lessons learned.

Today I completed the filleting and taping of the side tanks  & seats.  Here's a picture that shows the fillets in, but not yet taped.

I ran into a couple of problems that won't be of any interest to experienced builders on the forum, so this is for the first-timers like myself.

Lesson 1:   The seat front stringers need to be supported in the middle.   This won't be an issue for kit builders, but I'm building from plans and that gives me enough wiggle room to get in trouble.  Sure enough, the dimension is right there in the plans showing how far the seat tops should be below the sheer, but I missed it.  I'll spare you the gory details of the sawing, but in recovering from that mistake l learned ...

Lesson 2:   A heat gun is great for epoxy do-overs.  Epoxy doesn't melt, but it has a "glass transition"  where it turns rubbery, kind of like dried rubber cement, but tougher.  Still, in this rubbery state it's no match for a knife blade.    It's nice to know you can have a do-over, and you can remove stray epoxy blobs without sanding.   What I don't know is whether the epoxy is still strong after it has cooled back down.

Lesson 3:  Put the tape down while the fillets are still a little soft.  I made filleting tools for the different angles I would be filling and I was really pleased with the results.  I did all 4 tanks, but little goobers and peaks and imperfections had hardened in before I started with the tape, and that made the tape not want to lie down flat.    It would have been best to do the taping while the goo in the fillets was firmed up, but still squishable.

\begin{geekout}

The formula for the filleting tool radius is

Radius = 3 * ply_thickness * tan( angle / 2 ).

This gives fillets that extend three ply thicknesses away from the corner.

\end{geekout}

Best,

Bob

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How 'bout that.  I just learned something about the edit button.

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\begin{geekout}

The formula for the filleting tool radius is

Radius = 3 * ply_thickness * tan( angle / 2 ).

This gives fillets that extend three ply thicknesses away from the corner.

\end{geekout}

Good judgement comes from experience.

Experience comes from bad judgement.

-- Cowboy Wisdom

Best,

Bob

Bob:

Where did you find this formula? I've seen the first part (re: radius = 3x ply thickness) in numerous locations, but none of those included the last part, which expands the formula to take into account the angle of the joint. This was discussed in the epoxy tricks thread, starting with post #30:

We kicked it around a lot, but still find no mention of modifying the 3x formula to account for the angle. Makes sense to do so, just not sure why none of the other reference sources mentioned it.

So to put some numbers to your formula, assume 1/2" plywood and three joint options:

90 degree joint

120 degree obtuse joint

60 degree acute joint

90 degree joint:

r = (3 * .5) x tan (90 / 2)

r = 1.5 x tan 45

r = 1.5 x 1.0

r = 1.5  (diameter of tool is then 3 inches)

120 degree obtuse joint:

r = (3 * .5) x tan (120 / 2)

r = 1.5 x tan 60

r = 1.5 x 1.732

r = 2.598  (diameter of tool is then 5.196 inches : or somewhere around 5 to 5 1/4 inches would work - PAR's reference to the 4.75" CD might also work)

60 degree acute joint:

r = (3 * .5) x tan (60 / 2)

r = 1.5 x tan 30

r = 1.5 x 0.577

r = 0.866  (diameter of tool is then 1.732 inches: or 1.75 inches)

Experience tells me these would make sense. Still curious where you found the formula to include the modification using tangent of the angle?

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BTW, one of my quick and dirty methods of making a radius tool for fillets is to use hole saws. Punch a hole through scrap plywood or cheap luan subfloor base and save the part left inside the hole saw. It helps that I have a collection of hole saws from 1" all the way up to 6". If you feel the need to have a handle on it, leave a wet epoxy mixing stick on one edge.

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Hi Howard,

Like you, I have seen the "three thickness" guide in several places.  The tangent add-on is something I came up with using a little trigonometry.  I can easily generate a table or spreadsheet if anyone is interested.  Here's the derivation:

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Chuck over at DuckWorks published this a few weeks ago, when he was in need of some filler for his magazine.

The whole article is here and from the "Liquid Joinery" part of my site.

http://www.duckworksmagazine.com/15/howto/liquid/index.htm#.ViG2D9KrRhE

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Chuck published it, but you wrote it!   I hadn't seen the back cutting idea before.   It makes sense.  Thanks for that.

Bob

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With taped seam builds (stitch and glue is one method) you can hack the parts out with a hatchet and glue them together. In fact, if done this way, you'd probably have a stronger boat, because the goo would fill the ragged seams better than a saw cut one. Back cutting the joints can and should be quite sloppy. Two basic reasons; the first is to get epoxy around the end grain, protecting it. This is the most vulnerable edge, so special consideration should be taken on all exposed end grain. The other major issue is to decrease point loading, along the intersection of the parts. The fillet to a large degree does this if shaped properly, but minimizing the contact patch can help, so coupled with the advantage of getting goo to surround the end grain, a wise technique to incorporate into any build.

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HI All,

I've been sitting in the moaning chair some lately, and I could use some advice.   Despite taking care, I have somehow developed a 1 deg. twist in my hull.  It doesn't sound like much, but 1 deg. amounts to having the starbord inwhale 3/4" lower than the port at the forward bulkhead.  Now that I've noticed it, I can't unsee it.

If I have to saw out fillets to fix it, well, that's what I'll do, but I came up with this idea to double-up the inwhale in spots to push the sagging side in a little.  Maybe the seat back stringers, too.  In the picture, I have clamped on 1x2, and it pushes things in the right direction.

If that's a bad idea, I think the other plan would be to saw out the forward bulkhead first, replacing it with a temporary thwart, saw out the bulkheads in the side tanks, and start sawing out chine fillets working from bulkhead to stern, rewiring the joint as I go until the hull is flexible enough to hold the right shape easily.

Bob

Update:  I think it helped a lot just to write the problem down.    I ended up "editing" the center bulkheads in the seat tanks, pushing the port side out and pulling the starboard in.  These points seem to affect the twist a lot.   In all, it wasn't as painful as I had feared.

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Happy Veterans Day!

I celebrated our hard-won freedom by doing exactly what I wanted to do today.

I was jealous of the pre-carved notches in the CS15 kit that hold transverse framing in place between the seat fronts.  For example around the centerboard case, and across the front of the stern locker.  So, I built myself this little jig for my router.  It clamps over the edge of a  piece of material, and produces a 1" x 3/4" notch.  The corners are rounded, of course, so I just whack off the corners of the framing piece.

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Just a quick update on my build.

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