Scout Build in Boston

[dbp1]

I'm 33hrs into a new build, so thought I'd create a thread. It's Duckwork's Scout, which is a 10'6" stitch & glue boat that they originally claimed had a 65lb unpainted hull weight. This is intended to be a very cartoppable boat, as many of the nearest places to get on the water to me don't have ramps, so my primary aim is to keep the weight as low as possible.

While the last boat I built (linked in signature) is also stitch & glue, this boat is much more "composite". All the plywood is 4mm, and it all gets glassed with 4oz glass on both sides (a few places with two layers), and there is a bit of foam: the deck is entirely foam (glassed on both sides), the foils, the keel, a doubler for the transom, and for the gunwales.

Despite them now primarily offering it with a daggerboard, I asked for, and after a bit, was given what was originally designed: a pivoting centerboard (to match the kick up rudder). Unfortunately, it seems that the designer reconfigured a bunch of stuff and there are still instructions missing, but hopefully they'll get filled in before too long!

I'm keeping all the photos in this album, primarily as a reference for anyone else building this boat: https://www.icloud.com/sharedalbum/#B0Z5qXGF1G9OOgS , but I'll post normal photos as attachments in this thread as well.

Since I'll be building this in a very small space (with only one side accessible); essentially, the benches that run along the shop side of my garage, I wanted to do all of the assembly that I could before starting to assemble the hull.

This involved glassing most of the plywood pieces, some on both sides. For example, there are two (movable) seats that each are made up of many pieces; this was all of those getting glassed (and then flipped and the same on the reverse):

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Each of the planks were in multiple pieces, with puzzle joints to attach them. The instructions suggested using thin CA glue with an accelerator to join them, since the glass on both sides would be what is structural anyway, which ended up being very convenient, as it cures instantly, can then be sanded and glassed without delay. The thin glue is like water when it comes out of the bottle, so runs right down into the (quite tight) joints:

IMG_4842.jpg

Most of the work, towards the beginning, was just glassing planks, either one side (what will be the inside) or both (in the case of the bottom, or the top plank which will not get glassed on the outside).

Since my goal is to minimize weight, the parts that would be outside I used peel ply (as those surfaces will need to be sanded to get another layer of glass), but on the inside, I just used a layer of glass, saturated but with no fill coat. This will leave a textured surface, but I don't mind that, and all of the strength should already be there (this idea came from Todd on this forum, and also in Bill Thomas's videos at OffCenterHarbor).

I also built the seats (not completed, as they need more layers of glass):

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The foam deck also comes in pieces; some of the puzzle joints were a little damaged, which I tried to fix before assembling. All of the foam was supposed to have a fairing coat put on first. The instructions suggested adding the glass right away, but I went with advice from the Youtube channel "Sailing Magic Carpet" (who built a Scout and documented it in three videos) to let it cure and sand first. The kit came with one pack of fairing compound, but it's definitely not enough: even with half a pack left over from before, I still ended up needing to use a lot of regular epoxy mixed with lightweight fillers (not a big deal, but even the fast epoxy that I have cures a lot slower).

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At this point, I've done all of the major pre-glassing, and also essentially finished the foils (they have all the glass on them, thought still need some sanding and more epoxy). Today, after sanding off the edges of all the planks & redrilling the holes for stitching, I started assembly.

First, that involves putting together a bow & stern jig. Mine seemed to be missing a part (the shipping crate was damaged, so I suspect it slipped out, as it's quite small), so I had to make one. Then I leveled the two jigs with a laser:

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And finally started stitching: first the transom (which slots in to the bottom plank as well as stitches to all of them), and then the first planks. the near side is pretty easy; the far is hard, but doable. All the stitches are left loose, for now, so that the alignment can be fine tuned once all the pieces are stitched on. The flat bottom is nice, as I can set the laser level _inside_ the boat and see that both sides are in alignment (since I know the jigs are).

[dbp1]

Re: Scout Build in Boston

The last photo couldn't be included (5 photo limit -- I thought it was 6!).

IMG_4960.jpg

[Rich Jones]

Re: Scout Build in Boston

Looking good!

[dbp1]

Re: Scout Build in Boston

Up to just shy of 50hrs, so maybe worth an update.

I stitched the rest of the hull together, which was only difficult because of where I'm building the boat. With easy access to all sides, this would be pretty easy (eventually I started crawling down the far side, as I had to, but it's not easy to get up there):

IMG_4966.jpg

I spent a while making sure everything was level with the laser before tightening up the zip ties. I was still waiting on some details about the centerboard case, so didn't tie that in yet, and the deck doubler couldn't go on until that went on, and I was a little nervous that the boat might shift from moisture or who knows what, so I started spot gluing between the ties (the instructions say you should wait until everything is tied together, which makes sense).

Eventually, I did figure out what was going on with the centerboard case (there were two questions, one was wondering the pivot bolt dimensions, which it turns out they'd forgot to send it in the kit, and the other was an unexplained doubler, but once I mocked everything with the provided spacers, it became obvious that it had to go on the inboard side of the longitudinal bulkhead. Hopefully the instructions will get updated, but things seem quite slow with the designer). I drilled an oversized hole, filled with epoxy, and then redrilled the proper size hole on the centercase side. It's unfortunately the _outboard_ piece, which will be awkward to drill through to the other side, but that's the only place where a scribe mark was made for the kit...

I then stitched in the centerboard case. There were no stitch holes, unlike in the rest of the CNC cut parts, but easy to add. The more troublesome part is that you are zip tying a closed box (the bottom isn't cut until later), so you have to leave the whole thing half open in order to actually fit the ties through. A bit fiddly (and longer ties would have made it easier), but all worked out fine.

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Once everything was spot glued between the zip ties (which, on the underside of the deck doubler and bulkheads, is difficult. A mirror would have made it easier, which I used to have lying around; I ended up using my phone with the reverse camera turned on for a bit, but that's stressful when dealing with epoxy!).

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Then it was time to cut all the ties, sand anywhere I hadn't cleaned up the spot fillets well enough, and glass along the bottom several chines. There are a bunch of clever, weight-saving tricks on this boat, but one of the neatest I've noticed so far is that the top strake is lapstrake, which I initially thought was for looks (it may be), but it also provides the outboard bearing surface for the yet-to-be-installed deck.

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I still have to run full length fillets along all of the bulkheads, though I think I'm going to do it two stages: first the accessible stuff, and then, once that cures, I'll flip the boat over (it should be plenty stiff enough) and do the undersides from below.

[Liberty53]

Re: Scout Build in Boston

Looks great!

The pivoting centerboard is a sweet mod.

-Derek

[WI-Tom]

Re: Scout Build in Boston

Watching with great interest--such a neat little light-weight boat.

Tom

[dbp1]

Re: Scout Build in Boston

Looks great!

The pivoting centerboard is a sweet mod.

-Derek

It really makes sense... not sure why it isn't standard. Since the normal main downside, losing a bunch of valuable real estate in the center of the boat, is pretty much completely avoided since the case is already offcenter, tucked into the side tank. You lose a marginal amount of space in that tank, and other than that... I guess a little speed with the open slot, and a potential source for leaks (though the pivot pin may actually be above the waterline).

[dbp1]

Re: Scout Build in Boston

A little more progress, and some deviations from their order of operations:

1. There is a CNC cut hole through the stem, presumably to tie a loop through. It was _almost_ big enough to fit one of the phenolic tubes (that'll make more of an appearance in the gunwales), so I carefully enlarged the holes with a 5/8"s bit and glued in a bit. On the inside, a fillet runs up the stem, with enough extra epoxy around the tube to completely encapsulate it. No word what the original intention was, but seems like this will work.
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2. I then ran full length fillets everywhere that was accessible from above. This took a bit of time! And definitely appreciating following Russel Brown's filleting strategy, which is to use a radiused stick to form a fillet with a bit of pressure, so the extra is forced to the outside, with essentially a clean edge between (hard to describe, just buy his $5 book), and then use a really sharp stick (he uses pieces of G10, that I'm sure work better, but I used a tongue depressor cut at 45) to remove that extra. Since that extra is separate from the actual fillet, if your stick is sharp enough, you can scrape along without touching the fillet itself, and end up with pretty clean results. The only hard part is not forgetting to do this (and do it _everywhere_).

3. Finally, rather than going right to flipping to get easier access to the under the deck fillets, I decided to put the gunwales on now. The boat should be pretty much locked into shape, but the gunwales will lock in completely, so once that happens, lifting it up, flipping it over, etc, should be fine to go without worrying around it deforming (I was a little worried about it sitting upside down on saw horses without the gunwales might have put some unfairness in the sheer, and that _maybe_ the fillets in the underside of the deck could have locked some of that in. Unlikely, probably, with all the other stuff already glassed / filleted, but since nothing is preventing the gunwales from going in now, no reason to chance it).

The gunwales are a box, with the center being a 1" x ~2" piece of foam (the outside in the top strake, and the inside, top, and bottom are pieces of plywood, yet to be installed). It took a _lot_ of clamps to get nice squeeze out, and since I ran out of the spring clamps I had, I ended up having to use a bunch of heavier clamps as well:
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This was annoying because it weighed down this side of the boat (it's a light boat!), and slightly picked it up off of the jigs on the other side. I was worried that might introduce some unfairness (and I had no more clamps, so certainly couldn't get the other foam piece in at the same time), so ended up just weighing down the other side with some big C clamps and a little sledge. Hopefully all will be okay!

To avoid that on the other side (and just for convenience), I got some more cheap clamps for the other side (I didn't have PVC lying around, and clamps are more versatile!), which made that a bit easier:

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At the same time, part of the breasthook went in. Earlier, a plywood bottom to it was added to the foam, and when the gunwale top cap goes on, there is a plywood cap that'll go on top of the whole thing.

Once that cures, the inner plywood pieces go on, and the once those are cured (I'm hoping I have enough clamps both can go on at once!), the top & bottom caps go on at the same time.

-----

One random note: something I figured out a while back, that may be worth sharing.

I mix epoxy by weight, as trying to use measuring marks means you need special containers (and limits you to certain volumes), and I've had pumps give out partial pump-fulls that I don't trust them (and don't want to waste a pump before every session to make sure it's working). But the weight ratio, at least for the System 3 Silvertip Epoxy that I use, is 1 : 0.44, which is not an easy thing to calculate in your head (by volume it's 2:1...).

Obviously, if you end up with round numbers (100g, 75g, 50g, etc) of resin, then figuring out the hardener number is easy (44g, 33g, 22g, etc), but if you accidentally add a bit too much (104g resin), it becomes a pain. My understanding is that these nice epoxies are a little bit forgiving of slight mistakes, but I'd really rather not mess with something that is avoidable!

And, like probably some of you, I have one of these goofy watches on my wrist that is actually a little computer, and this is the first actually useful use for "Siri" that I've found: you can use your other arm to hold the button to activate it (in case your gloves are dirty), and ask "104 times 0.44" and it'll tell you. And if you end up going past (e.g., if you meant to put in 20g of hardener, and put in 23g instead), you just ask "3g divided by 0.44" and get how much more resin to add. Initially I was worried about wearing the watch in the shop, but I've been doing this for a couple years and haven't gotten epoxy (or anything else gross) on it yet, so...

[Paul356]

Re: Scout Build in Boston

fwiw, i'm running a similar Scout-build tale on the Design forum. Someone had started a Scout topic there, so I just added on. Similar photos, I'd say.

[dbp1]

Re: Scout Build in Boston

fwiw, i'm running a similar Scout-build tale on the Design forum. Someone had started a Scout topic there, so I just added on. Similar photos, I'd say.

yup, I’ve seen (and commented, I think?) on your thread. Curious where you are now!

[Autonomous]

Re: Scout Build in Boston

Daniel, have you seen the balance Joe Tribulato came up with?

_Epoxybalance.pdf (duckworks.s3.amazonaws.com)
Duckworks (duckworksmagazine.com)

[dbp1]

Re: Scout Build in Boston

Daniel, have you seen the balance Joe Tribulato came up with?

_Epoxybalance.pdf (duckworks.s3.amazonaws.com)
Duckworks (duckworksmagazine.com)

Clever! Though with cheap digital scales that are accurate to sub gram levels, it’s hard to motivate to build anything

[Paul356]

Re: Scout Build in Boston

I just glued the deck on this week. Posted some photos on that thread. Brought it home to work on, hoping for faster progress now. I think my hours-invested are on track with yours. Can't wait to sail. There's a meet-up on June 10 I'm hoping to make.

[dbp1]

Re: Scout Build in Boston

Not a ton of progress, but I finished putting on the gunwales (inner, top / bottom) and breasthook. They still need to be trimmed / sanded, and then rounded / wrapped with glass, but the boat is now stiff enough that I feel fine moving it around, so took the opportunity to bring it outside and weigh it!

Sort of silly to do at this point, but I was curious, and despite there being a bit of work left to do, the only major component that still needs to go on is the deck (which is 1/4" foam with a layer of 4oz glass on either side, so not very heavy), plus a layer of 4oz glass on the outside that I'm sure will bring a bit of weight in resin with it. And of course still plenty of little bits (some fillets, the aforementioned glass on the gunwales, some more epoxy coating, and then of course paint).

The current weight, at 48.8lbs, is quite encouraging! I'll definitely repeat once it's done (and maybe before!). Nice to have a boat light enough that I can weigh it from the swingset I made for my kid (swing temporarily removed).

IMG_5097.jpg

[dbp1]

Re: Scout Build in Boston

70 hours today, and just finished gluing down the deck.

Before that, I rounded over the three corners of the gunwales with a 1/4" roundover bit on a trim router. The top two edges were easy, but to get the lower inside edge I had to sand the inside face flush first so the router could ride along it smoothly (since the upper and lower plywood caps overlap slightly).

IMG_5105.jpg

It still needs 4oz glass wrapped around the whole thing, and holes drilled out for phenolic tubes (and on a few, oarlocks), marked with the +. Before the glass can be done, a fillet had to go along the corner underneath, and I still had to run fillets on the underside of the deck doubler and most of the bulkheads (I had spot filleted them, but delayed the full length ones given how much of a pain it was to do right side up).

So I picked the boat up, carried it outside, stuck it up on some saw horses, and did those from beneath.

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Next, in preparation for putting the decks on, I sanded, primed, and painted the inside. This isn't strictly necessary (it's all been epoxy coated, and most glassed), but the light color paint should make it easier to find stuff inside. To save on paint (and weight!) I only did a single coat of primer (epifanes epoxy primer) and a single top coat (epifanes two-part poly, arctic white). Even the primer alone would have probably been enough, but it didn't seem right. The more visible areas will certainly need more -- probably two coats of primer, and certainly two, possibly more, coats of paint.

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Then I had to do the final prep of the deck. Not only trimming off the excess glass and sanding it to shape, but cutting the holes for the centerboard slot & the holes for the hatches. I opted for armstrong hatches, rather than whatever they suggested in their kit, as I've used them and like them. Both the 8" hatches (to the side) and the 10" hatch (at the front) required a hole about 1cm bigger all around than the line that was marked on the foam, but that was pretty easy to cut without marking anything else.

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Finally, it was time to dry-fit, trim to fit (I had to cut off a tiny bit towards the bow) and then glue down. Thickened epoxy goes on all the bearing surfaces (including very stiff stuff on the top edges of the 4mm bulkheads), and then the deck goes down, is clamped / weighted however needed to get it to sit on its line (which towards the middle is on the deck doubler, and on the outside is the exposed edge of the plank that the lapstrake upper strake gives). Once that happens, a fillet is run around the entire outside perimeter.

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Probably that's the last that I'm going to be able to work on it for a little bit, as I'm going on a trip for about a week, but looking forward to finishing up the inside (mast step, glass on the gunwales, paint) once I get back, and then flipping it and finishing the outside (fairing, 4oz glass, paint). Then it's just the little stuff: finishing the seats / rudder case, installing the rudder hardware, centerboard, etc.