Boat in a box - the Shu3

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Shu
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Re: Boat in a box - the Shu3

Post by Shu » Thu Feb 13, 2014 12:37 am

True Paul. The rudder foil lets us get away with much less rocker. I was much more tentative about reducing rocker in the Shu2, but after seeing the success of the B6 with very little rocker, I said "why not". It's not entirely reliant on the rudder foils though. The rounder bow sections should provide some relief downwind and in bear-aways.
Steve Shumaker
USA 1183

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Shu
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Re: Boat in a box - the Shu3

Post by Shu » Wed Mar 26, 2014 6:42 pm

I glued the daggerboard box together this morning. Here's a photo history of the work leading up to this morning's accomplishment.

Rather than use the vacuum pump, I just made a dagwood sandwich to laminate the carbon faces to the box's side panels. Starting with breather cloth, then peel-ply, wet-out carbon cloth, plywood, carbon cloth, peel-ply, breather, plastic film, breather, peel-ply, carbon, plywood, carbon, peel-ply, breather plastic film, 3/8 plywood, and 200 lbs of lead. 200 lbs sounds like a lot, but it's only about 1.4 psi, alot less than you can achieve with a vacuum pump.
Attachments
IMG_3111.JPG
I added a layer of 200 gm carbon cloth to each side of the girder to stiffen it up under the mast step. Once this was done, the girders were glued in place, with 1/2" epoxy fillets on all sides of the glue joints (except at the temporary frames!). After that I added 1.5" x 1.375" pieces to the ends of the girder to form the front and back of the daggerboard box.
IMG_3100.JPG
two 3mm okoume plywood panels for the daggerboard case side panels sealed with epoxy prior to laminating one layer of 200 gm carbon cloth to each side.
IMG_3106.JPG
The side panels with the inside faces finished with two more coats of epoxy.
IMG_3103.JPG
Gluing a thin Carbon plate to the back of the box; it's hidden beneath the plywood. This should help the impact zone hold together. Hey Hendo, I'll see your clamps and raise you two!
IMG_3109.JPG
The finished back of the box.
IMG_3113.JPG
One side fit in place.
IMG_3114.JPG
The wood strips are temporarily clamped to the box sides to keep them flat as the epoxy cures.
Steve Shumaker
USA 1183

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Shu
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Re: Boat in a box - the Shu3

Post by Shu » Wed Mar 26, 2014 7:17 pm

It's funny to compare the two boat building methods shown here on this website: I'm building the boat from the inside out, and Hendo's building it from the outside in. In the very early days of FRP boat construction, one boatbuilder quipped, "It's the first time I started with the paint and built the boat inside of that."
Steve Shumaker
USA 1183

joe.bersch
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Re: Boat in a box - the Shu3

Post by joe.bersch » Thu Mar 27, 2014 12:19 am

Steve:

I love to watch your progress. Keep on posting.

Regarding rocker, it has been a while since I sailed a B5, but the B6 doesn't really sail like a boat with less rocker than the B5. The biggest difference between the 5/6 is the fullness in the bow. You can really press the bow down with the foil or with crew weight and not start to trip over it. This also allows for very easy bear aways without really easing the foil. Huge difference in feel versus the B5. In San Diego, I would sometimes catch Leith just smiling while looking at the bow. Seems he had a hard time getting over it!

I like your analogy of building the boat from the outside in. Don't forget, however, that we first built a plug in similar fashion to your project. It is probably heavier than the Shu 3 and I doubt it would hold rig tension over about 15 though!! Your craftsmanship is beautiful. Keep up the good work. You are inspiring.

Joe

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Re: Boat in a box - the Shu3

Post by Hendo » Sun Mar 30, 2014 5:33 am

Shu, Don't even go there on the clamps, we have over 100 clamps from 6' pipe clamps to "pincher"clamps the size of a close pin.
Boat looks great, just keep her light!

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Shu
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Re: Boat in a box - the Shu3

Post by Shu » Mon Mar 31, 2014 4:24 pm

Joe,
By my count, at least 5 of the top ten boats at Toronto had the fuller, straighter bow we are talking about.

Kris,
I'm sure I have at least that many clamps. My dad knew that to build a boat, you need a lot of clamps, and as you noted, a wide variety of shapes and sizes.
-Steve
Steve Shumaker
USA 1183

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Re: Boat in a box - the Shu3

Post by Shu » Wed Apr 09, 2014 6:34 pm

My boat is in the container waiting to be shipped to Hawaii. I need an I-14 fix. Somebody please post something! I've got some more progress photos on the daggerboard case for the Shu 3.
I put a large number of 2.5" x #10 bronze screws through the ends of the case. The wood pieces here are the most massive on the entire boat, but they are loaded primarily in shear in the same plane as the grain, so they are not particularly strong. The bronze screws should help. I've added two layers of 200 gm carbon fiber cloth tabbing at the transitions, again to strengthen the connection between the centerline girder and the case. The forward corners of the case have been routed with a 3/8" bit to facilitate laying the cloth around this corner. The inside corners were filleted with thickened epoxy using a tongue depressor, again to allow a smooth transition from one surface to another for the carbon cloth.
Attachments
IMG_3117.JPG
Sealing all around the screw heads with liquid epoxy.I don't want these knowing that they are in a marine environment, but being silicon bronze, they will be fine if seawater finds its way to them.
IMG_3118.JPG
The screw heads are filled with thickened epoxy.
IMG_3119.JPG
Two layers of carbon tabbing cut at 45/45, topped with peel ply to help consolidate the laminate. It's not really visible here, but the edges of the two layers are offset about 1/2" to taper the reinforcement.
IMG_3120.JPG
And two layers of tabbing on the backside as well.
Steve Shumaker
USA 1183

EdS
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Re: Boat in a box - the Shu3

Post by EdS » Thu Apr 10, 2014 10:05 pm

Steve, I have a boat which needs several little bimbles, but being sat in Norway semi permanently doesn't help that.

great to see the new boat coming along,

you have made the daggerboard slot a rectangle again, are you going to try a gyber this time or plans to use a new daggerboard in the near future?
just wondering why you wouldn't make a moulding of the foil and set it into the boat which might be lighter but not flexible in future without doing surgery.

list for me when i manage to get home - make a gooseneck, bond on spreaders and more urgently find a better way of trimming the jib. we are pointing like a dog and i think it is because the car is always right out, possibly sheeting angle as well since the new rig went in.

something you might find interesting, i put a 14mm antal ring as the spinnaker mast head sheave and it is less friction than the harken block it replaced because alignment isn't such as issue, i have an external halyard going round the starboard side of the rig.
my crew is actually thanking me for it, bit of a surprise.
Roaring Forties GBR1524

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rand
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Re: Boat in a box - the Shu3

Post by rand » Fri Apr 11, 2014 2:18 am

I've got a question, why bronze and not stainless?

For a 14 fix, come on up to RYC this weekend, there are plenty of boats that can't seem to get wet, I'm sure we can pry one loose for you, and there is even an experienced crew available!

The local boys don't load for Hawaii until Monday.
Rand Arnold
International 14 USA 1143
"A Bumblebee Called Kate"
(former US President, former US Measurer)

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Re: Boat in a box - the Shu3

Post by Andrew P » Fri Apr 11, 2014 5:13 am

EdS wrote: we are pointing like a dog and i think it is because the car is always right out, possibly sheeting angle as well since the new rig went in.

.

most boats are sailing with the jib on the gunwhale at all times nowdays. Seems like if the mid leech is tight enough then the flow dragged through the slot will bend the jib upwash that it doesn't matter.

I would focus on mast tip layoff, leech load and mainsail depth before worrying about the jib sheeting position.

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Re: Boat in a box - the Shu3

Post by Shu » Fri Apr 11, 2014 5:13 pm

Ed,
If your crew is thanking you, you may want to reconsider; something must be wrong :lol:

My boat is a little narrower on the deck than a B5 and I almost never sheet the jib all the way out. I think Andrew has it right though, getting leach tension on the main makes a huge difference in pointing ability. Sometimes a serious pull on the vang can get me 10 degrees. If your mast tip is too soft though, the mast just bends more when you pull on vang, and you don't get a significant increase in leach tension.

Rand,
Sounds great, but saving $ for Hawaii, so a trip to the Bay area right now is out.
-Steve
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Re: Boat in a box - the Shu3

Post by Shu » Fri Apr 11, 2014 5:43 pm

Rand,
Bronze is more expensive and slightly heavier than stainless, so obviously its the right choice. :wink:

I like using bronze where it is unlikely to be exposed to air. Stainless needs oxygen to develop (and keep) the chromium oxide protective layer that makes it resist corrosion. Notice how the threads on your stainless screws are always a bit rusty when you remove them?

If my boat construction was perfect and I never ran aground, stainless screws in this location would never see any saltwater, so it wouldn't matter. But construction isn't perfect, and last Pac Rims proved my ability to run aground, so it's nice to know that my bronze screws in the Shu2 are still fine.
-Steve
Steve Shumaker
USA 1183

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Re: Boat in a box - the Shu3

Post by rand » Fri Apr 11, 2014 6:27 pm

That explanation is why I love this fleet, learning something new all the time!

Thank you!
Rand Arnold
International 14 USA 1143
"A Bumblebee Called Kate"
(former US President, former US Measurer)

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Shu
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Re: Boat in a box - the Shu3

Post by Shu » Mon Apr 14, 2014 4:51 pm

I totally agree Rand.
It's amazing how much I've learned just on my own threads. People will make suggestions, or, even ask a question that I have to think through to come up with an answer.

Here's a few more photos that show:
1. the cleat I've glued onto the bottom of the centerboard case. This will form the basis for the joint between the hull skin and the case, letting me easily glue and (temporarily) screw the skin on.

2. the forward bottom of the centerboard case is now braced to keep it on the centerline, and the top (currently the bottom) is braced to keep it vertical.

I also ripped all the stringers this weekend and then used a router with a roundover bit on their exposed (inner) edges. This does two things: 1) matches the diameter of the router bit that was used to CNC the stringer slots into the bulkheads, and 2) gets rid of the sharp corner, to which it is difficult to get a decent thickness of epoxy sealer. Sorry, no pics of the stringers yet. Since the stringers are Port Orford cedar, the shop, my clothes, and even my hair smelled great.
Attachments
IMG_3123.JPG
Cleats glued to the bottom of the daggerboard case
IMG_3125.JPG
A brace to keep the bottom of the daggerboard case on the centerline
IMG_3128.JPG
A brace to keep the top of the daggerboard case vertical with respect to the bottom
Steve Shumaker
USA 1183

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Shu
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Re: Boat in a box - the Shu3

Post by Shu » Tue Apr 15, 2014 5:39 pm

Stringers!
This is the best part. With relatively little work it defines the shape of the boat so well. Also, the stringers are very close to the flowlines as the boat moves through the water. I can just imagine the water molecules zipping along the hull.

I went through some of my dad's old stock of Port Orford cedar in 16'+ long planks which had beautiful straight grain, but some old splits and the occasional knot. I suspect that some of the splits happened when the tree was felled, since the unweathered splits seemed to be filled with crystalized sap. Anyway, it took a lot of carefull selection and ripping to get the stringers. One of the most beautiful, straight-grained planks had a pair of knots that ran accross the width of the board near the middle. I decided to use this for the two chine logs, as the angle of the chine allows the hull skin to take the load once it's all glued up. However, they started to crack at the knots when I started bending them around the frames.

This was a real problem, since the resulting weakness and cracking would result in the chine log not taking a fair curve. I decided to reinforce the outside (tension side) of the chine logs with a couple layers of 200 gm carbon cloth. First I rasped down the thickness of the wood to accommodate the thickness of the carbon and then layed it up, making sure to thoroughly soak the wood with epoxy first, so it didn't suck the epoxy out of the carbon cloth during the cure. A bit of trimming and sanding of the carbon, and I've got a pair of good chine logs.
Attachments
IMG_3133.JPG
Stringers 1, 2, 3, and 4. Only 1 and 2 are completely fitted and ready to be glued. Stringer one gets a plywood strip that serves as a doubler between the center panel and the cold-molded part of the hull bottom.
IMG_3130.JPG
A couple of layers of carbon over the knot area of the chine logs.
IMG_3131.JPG
Sanded and ready for use
Steve Shumaker
USA 1183

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