20+ Footer - Building in Hawaii

Jim Donovan

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Laser level set on some wood chunks inside the boat established tank tops.
Made some carbon angle over a 2 x 4 "mold" to form a carbon channel; split it in half and get two carbon angles. Those angles get bonded to the bhds and hull, and the the tank tops simply glue down onto those.

Glued down the aft tank top and then applied a fillet at the hull intersection; peel plied that fillet so it's 100% ready for a covering laminate.

Mast partner/step will be adjustable on Hull 1 so I can "tune" the rig placement; I'll have 60mm F&A and +/- 3 degrees of rake available.
Center tank is waiting for the daggerboard so I can sort out the trunk; going to build that so we can adjust the board rake a few degrees aft.

Laser Level.jpg


Peel Ply on Fillet.jpg
 

Jim Donovan

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Thanks Russell!

We had our third class today, laminating the inner carbon skin on Hull 2.
Vermont has had 6 days in a row w/temps over 90 degrees; it's hotter than Hawaii!

Today when we started laminating it was 75 degrees, and when finished, it was 88.
But we pulled it off and the laminate looks really good.

The teaching method involves working together and w/pointers from the instructors; basically you build a boat.
It's exactly the same dynamic as working in any boat shop; the experienced guys tell the less experienced what to do, and then watch you, and then expect you to go for it - EVERYONE works.

We started with 3 students, and gained one more for the second class; really nice novice builders who are doing a great job.
The classes are only on Sundays, but Charlie continues building during the week with any willing student.

Hull 1 was built (not completed) before class one.

Class 1: Hull 2 stem, transom and bottom plank were set-up on the jig; carbon laminated onto foam tank panels

Between Class 1 and 2, Hull 2 was planked; took 20 hours total.

Class 2: (I missed this class) Hull 2 got epoxy fillets at the chines, exterior fiberglass sheathing, and first pass of fairing.

Between Class 2 and 3, Hull 2's rail was installed and Hull 3 was 75% planked.

Class 3: Hull 2 got it's interior carbon laminate, and then I'm not sure because I went back to work at my shop.

So we have our little fleet of three boats coming together quickly.

I'm slammed to finished some tasks in the shed, so the few tasks needed to get Hull 1 sailing have suffered a bit.
The dagger-board is built, and needs the leading edge bond and paint before we can use it as the mold for the trunk.

We've decided to use stock Laser "practice" masts for the spars, and we have a really nice "Byte" mainsail that looks about right.

I've designed a mast step and partners for Hull 1 that allows quite a lot adjustment, so we can figure out where the rig wants to be.
Once we decide that, we'll we'll build a simpler mast socket.

July 24 A.jpg
July 24 B.jpg
 

Jim Donovan

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And I really want to get the 20 launched this year!
It's sitting there waiting . . . it's so close and it'll happen.

But this dinghy project is interesting and bringing some local sailors together which wouldn't happen without this program.
And developing a nice fleet of fast boats on this beautiful lake.

It's all good.
 

Jim Donovan

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Hull 1 of the Split Rock Dinghy went sailing last week; reports were even better than I expected. Returning home after a month on the road, I'm ready to go sail the boat to see what I did. We installed an adjustable mast step/partners to allow a fairly large range of positions, so we can "tweak" the mast location to find the sweet spot for the other boats. Should have some photos soon.
 

Jim Donovan

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And now I can finally turn my attention back to the 20 footer, so expect more posts in the next months. The 20 footer is a smaller cousin of my GP 26 design, and just this week I got a video of the guys in the UK sailing GP26 Hull 3 in the open ocean;



Notice the small helm adjustments needed to steer the boat at very high speeds.
Note that it's only 26 feet long and is dragging along a 1000# keel.

At 55 secs into the video you see the boat rock up on a wave, heeling approx 15 degrees; the boat stays on a plane and the helmsman just shoves the bow down and keeps going as if nothing really happened. This is exactly what I wanted in this hull form; so you can always keep the throttle down.

The few times the boat over-runs the waves and sticks the bow in, the boat comes up and out with no drama.

The 20 footer is more powered up than the 26, so pretty interested to see how it goes . . .
 

Jim Donovan

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Got a daggerboard built for Hull 2 of the Split Rock Dinghies right after returning after a month on the road. Finally back to the 20.
Focused on getting the mast and boom "a paint job away" from completion. The mast step materials and plan had been staring at me from a cardboard box for months, so finally jumped in and built it; no budget to water-jet cut, or even machine any parts, so all made "by hand".

Trying out some "black" G-10 plate; just the very outer layer is pigmented and very shiny. After these photos, I sanded it with 600g and it definitely looks kind of like carbon . . .

The step has 3 parts;

Bottom plate will be glued to the keel frame
Sliding plate has a G-10 tongue that slots into the third part
The third part fits tight into the spar with a rockered bottom to allow for rake changes

The hole layout allows for 15mm adjustments; 30mm forward and 30 mm aft.
That moves the masthead 370mm (14") forward or 370mm aft, or 2 degrees F or 2 degrees aft (4 degrees total)


Mst Step 1.jpg Mast Step 2.jpg Mast Step 3.jpg Mast Step 4.jpg Mast Step 5.jpg
 

Jim Donovan

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Just a few things going on . . .

Getting the final hardware list sorted out; the 34 footer "dipped into" my hardware stash, so there's some parts missing.

With the square top main, I've decided to go with a pair of topmast backstays so we can control bend up wind, and have a stay to oppose a masthead genoa.

My friends Rob and Wes at Dynamic Yacht Rigging are building the stays now; using Maffioli SDK99 Ultra which has a longer braid angle that noticeably reduces stretch. For a few extra ounces, the stays are enormously overkill to avoid the inevitable "creep" that occurs with dyneema.

Halyard slots are cut in the mast, it's 99.9% primed - just needs some tiny amounts of filler in a couple spots.

Designed and built a tall cradle for the boat so I can fit the keel/bulb; it uses the trailer cradles on a wooden frame.

Lifted the boat off the trailer on Thursday and it's up on some jack stands now.
Weighed the boat an it's about 10kg within my really rough guess.

Cleaned inside, again.

I'll send some photos tomorrow.
 

Jim Donovan

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I think the boat's been sitting on that trailer for maybe 11 years?
It's gone about 10,000 miles on that trailer . . .

Removed the trailer cradles off the trailer this morning (only had to cut the heads off 4 bolts).
Lifted the trailer cradles up and screwed them to the high cradle.

Picked up the 20 using the "lift-thing" I built to pull the engine out of the 34 footer; it's basically a very strong garden gate bolted to the shed wall. It picked up the 34 footer's 420# bulb without making any bad noises, so I figured it could handle the 20 footer.

Rigged up the load cell when I lifted the 20.
215kg - 2.5kg of stuff on the boat = 212.5kg (468 lbs).
I had guessed the boat weighed about 450 lbs, so not a bad guess.
Happy with the lift point at the aft edge of the hatch; with the rig in the boat hopefully the CG will be exactly over the lifting eye on the keel fin.

I will need to use the trailer to move the bulb under then boat, so the high cradle is wide enough to back the trailer under the boat.
Then I'll lift the bulb off t he trailer and set it under the fin (I'll really check my lifting thing's strength when I lift the 620# bulb!)
The fin goes into the boat from the top, and I'll lower it down to the bulb.
There's a pair of 3/8" threaded rods that hold the weight of the bulb.

High cradle is reasonably stable; needs some diagonal bracing to make it more rigid.

20 Cradle 1.jpg
20 Cradle 2.jpg
20 Cradle 3.jpg
20 Cradle 4.jpg
 
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Jim Donovan

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Cradle padding is 1" thick EVA foam; scraps left over from T4's building cradle.
It's held up better than expected over the years; the boat slide forward about 6" during those 11 years, so the boat wasn't fitting perfectly in the cradles; that compressed the foam at the edges. Time to replace.
 

Jim Donovan

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Got the fin set into the boat for the first time today; the hole I cut in the hull bottom over ten years ago is just about perfect.
When I add the final layer around the fin, with an extra layer right at the hull bottom, it should be more perfect.

The bulb making it's way toward the fin on steel pipes . . . 20 Fin Install 1.JPG 20 Fin Install 2.JPG 20 Fin Install 3.JPG
 

JulianB

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