Boat in a box - the Shu3

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-TG
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Boat Number: USA 1187
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Re: Boat in a box - the Shu3

Post by -TG » Sat Apr 18, 2015 2:49 pm

Steve, do you have an extra building on the property to store all your clamps?
-TG
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Shu
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Re: Boat in a box - the Shu3

Post by Shu » Wed Apr 29, 2015 10:08 pm

Terry,
I have C-clamps racked in one spot, a box of spring clamps, and pile of bar-clamps. All are in the building the boat is being built in. However, we may need a new thread to hold all your snarky clamp comments :P
Steve Shumaker
USA 1183

-TG
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Re: Boat in a box - the Shu3

Post by -TG » Mon May 04, 2015 10:30 pm

Steve, I look forward to seeing your new boat bomb through all the waves in Richmond! For this one, are you going to do the same or different Carbon reinforcements? Are you going to do the Gantry like the new B6's?
-TG
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Shu
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Re: Boat in a box - the Shu3

Post by Shu » Tue May 05, 2015 12:32 am

Terry,
The carbon reinforcements will be similar to the Shu2. The gantry will be the same as the Shu2, which looks similar to the B6, other than the width. There are significant differences in the way they are constructed of course. The ends land on the stringer ends, which are at 8" spacing, so the gantry ends up being 16" wide instead of about 24" for the B6.
Steve Shumaker
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Shu
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Re: Boat in a box - the Shu3

Post by Shu » Wed Jun 03, 2015 9:55 pm

I've been making progress, but I've been lax in taking photos. Here are a few photos from about 3 weeks ago. In these photos, I've cut the 4 panels of 4mm plywood and fit them to the boat in preparation for scarfing the topside panels together. The outside ply grain runs up and down so the span is only about 6 inches maximum, making for stiff and strong topsides.

I don't have photos yet, but the port topside panel is scarfed together and ready to be glued to the boat. If I can get another pair of hands to help me, that could happen tonight.
Attachments
IMG_3729.JPG
The panels fit in place on the boat. I make the panels about 1.5 to 2 inches wider than their final width in order to allow some wiggle room when assembling the final 14'+ long panel.
IMG_3730.JPG
Overlapping the panel in preparation for the scarf joint. The joint is a 10:1 scarf; so for this 4mm plywood, the overlap is 40mm.
IMG_3732.JPG
Another view
Steve Shumaker
USA 1183

-TG
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Re: Boat in a box - the Shu3

Post by -TG » Thu Jun 04, 2015 4:57 pm

Steve, on that scarf joint... is that also along where your racks will go and thus some additional carbon?

great stuff... pure craftsmanship for sure!
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Shu
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Re: Boat in a box - the Shu3

Post by Shu » Thu Jun 04, 2015 5:14 pm

Terry,
I have tried to place the middle scarf joint under the unidirectional carbon I will run from the mast step area to the forward rack-strut/shroud attachement area. The other two scarf joints will be visible unless I paint the boat, which is looking likely.

Congratulations again to you and Evan for becoming our latest US National champions!
-Steve
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Shu
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Re: Boat in a box - the Shu3

Post by Shu » Thu Jun 04, 2015 5:40 pm

I glued the port topside panel on this morning. Here are a few photos. A couple of things to note on the preparation:
1. Getting the butt joint on the forward part of the chine to match reasonably well required quite a bit of trial and error cutting, planing, and sanding. The angle of the chine forward is just too small to be able to mark it with a pencil.
2. I get underneath/inside the boat and outline the stringers and panel edges with a pencil. This allows me to know where to apply the epoxy, and for the floor stringer, which is in the center of the panel, I can drive a thin wire nail at regular intervals between the marks to give me marks on the outside for placing/nailing/screwing the batten. I don't mark the temporary frames, or else I might forget and put glue there, eliminating their temporary aspect.
3. With the panel so fitted and marked, I can cut off most of the excess width, leaving only about 1/8" to 3/16" (3mm to 5mm for the imperially challenged).

As usual, I coated both sides of the glue joint with liquid epoxy, then prepared a silica-thickened epoxy paste and apply that to one side of the joint (the boat side in this case). Kim (my Kim, not Hendo's Kim) then helped me get the very wiggly panel onto the boat. After that it was a lot of nailing (where a small clamping force was sufficient; nails leave smaller holes), screwing (where I needed higher clamping force), and clamping (where the clamps could reach, and of course to keep -TG entertained).
Attachments
IMG_3816.JPG
The port topside panel with the glue joint (faying) surfaces painted with liquid epoxy.
IMG_3817.JPG
Aft end of the panel
IMG_3824.JPG
The port topside panel glued, screwed, nailed, and clamped to the boat. The plastic's purpose is to keep the forward chine battens from being glued to the boat.
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Shu
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Re: Boat in a box - the Shu3

Post by Shu » Mon Jun 08, 2015 5:39 pm

It's a hull!
Attachments
IMG_3832.JPG
IMG_3836.JPG
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rand
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Re: Boat in a box - the Shu3

Post by rand » Tue Jun 09, 2015 1:00 am

Not sure I'm up for bringing a rudder down for this one :) Looking forward to seeing it in person though!
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 Jun 15, 2015 4:49 pm

Before applying the outer carbon reinforcement, I'm preparing the daggerboard case. I Routed out the bottom skin flush with the inside of case using a flush router bit. I laminated the carbon bottom panel for the case with the following layup schedule:
200 gm cloth 0/90
300 gm uni 90
200 gm cloth 45/45
300 gm uni 90
200 gm cloth 0/90

Note: 0 degrees is along the longitudinal axis of the boat (fore and aft)
Attachments
IMG_3873.JPG
Centerboard case. It is 3-inches wide to accommodate a gybing cassette.
IMG_3870.JPG
Under all that lead is the carbon panel. I like to use System Three's laminating resin for laminates. It wets out easier, and is slightly stronger than the general purpose epoxy.
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Shu
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Re: Boat in a box - the Shu3

Post by Shu » Wed Jun 17, 2015 4:49 pm

I had more fun with the router. First I routed out recesses for 1/2" x 1/8" carbon bars (12mm x 3 mm for the imperially challenged)at the bottom of the daggerboard case. The bars will help distribute the point loads from the gybing cassette and mechanism. They only need to extend about 3/4 of the length aft from the front of the case. Next, I routed out a slight rebate in the hull around the case to accept the carbon plate, which was then trimmed to fit. the plate extends about 2" all around to allow plenty of glue surface. The routing was much trickier for this boat compared with the Shu2, since the hull curvature starts being noticeable at the forward end of the case.

The orientation of the uni-direction carbon layers (see laminate schedule above) made the plate fairly flexible fore and aft, but quite stiff athwartships.

I also rough cut the stem cap out of 1/2" (12mm) thick port orford cedar, and glued that to the stem.
Attachments
IMG_3876.JPG
Here the recess for the carbon bars, and the rebate for the carbon plate can be clearly seen.
IMG_3878.JPG
The carbon plate fit into its rebate. Note how the forward ends show the curvature of the hull. I will have to carefully apply weight along the edges to make it conform to the hull when it is glued down.
IMG_3879.JPG
Stem cap glued and screwed to the stem. The screws are temporary.
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rand
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Re: Boat in a box - the Shu3

Post by rand » Thu Jun 18, 2015 3:39 pm

No vacuum bagging?
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 » Thu Jun 18, 2015 5:09 pm

Last night I shaped the stem cap and the daggerboard case carbon bars.

The carbon bars were made from some carbon plate off-cuts that I bought from somebody's website. There are some less-than-workmanlike glitches in the routing visible in the photo; not only was the router tippy on the rounded parts of the hull, but the router housing broke part way through the job. Fortunately I had a spare housing, but not before the damage was done. Some epoxy filler without microballoons will take care of it.

I gave the stem cap a parabolic shape (at least to my eye) in cross-section. It is a bit blunter (thicker) than the stem on the Shu2. Quite a bit of work with a rasp and sandpaper was required on both the cap and the hull to get the cap to blend in with the hull at the curve of the knuckle.

After the tedium of skinning the hull, these short steps are fun. There's something new to show for my work with every session.
Attachments
IMG_3882.JPG
The carbon bars shaped to fit in their recesses. Note the routing errors.
IMG_3883.JPG
This view gives the illusion that nearly the entire stem has a flat front. Actually it has a near parabolic curvature up to about 2 inches (5cm) above (below with the boat in this position) the chine.
IMG_3884.JPG
This view indicates the curvature better.
IMG_3885.JPG
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Shu
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Re: Boat in a box - the Shu3

Post by Shu » Thu Jun 18, 2015 5:18 pm

rand wrote:No vacuum bagging?
Rand,
Vacuum bagging is a pain, and produces a lot of waste, so I prefer to use a lot of weight on small, flat pieces. The weight shown on that plate looks like a lot, but it only works out to about 1.5 psi, which is less than vacuum bagging. It seems to be enough to get good consolidation though. Unfortunately, the time to vacuum bag some hull reinforcement is on the horizon.
Steve Shumaker
USA 1183

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