Wooden Boat People
By McKenzieDriftBoat.com
Black Eagle mini dory (was: baby Briggs build)
I love my big 17' Jerry Briggs-inspired Grand Canyon dory from Andy Hutchinson's plans, but she's way too big for day runs. Time to build a little boat.
10'-6" LOA
60" beam
36" floor width
~23" deep at the oarlocks
I made three paper mockups, and two smaller 1:12 tagboard mockups. One final 1:6 cardboard mockup before committing to plywood:
Cut the plywood. One piece ripped diagonally lengthwise, the bow panels out of the width of another sheet. Side panels 11'-10"
I was having a hard time getting straight scarfs with my saw jig, so I cleaned them up from here with a ROS and 60-grit. You want the ramps to all touch the previous sheet and the glue lines parallel. The top piece was really ugly and got re-cut entirely. This isn't fancy AA marine ply, just $30 AC ply from the box store. Not worried about knots; I'll be glassing the entire boat inside and out.
I like woodgrain. Used a latex exterior stain. Oil based stains can interfere with the epoxy joint.
Epoxy on the joint faces and clamped/screwed for the night.
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Replies to This Discussion
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Permalink Reply by Shawn Baker on
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Here's the big boat in Chittam on the Main. Had maybe 1/2 gallon in the boat, and we were right in the meat.
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Got a funny for you, Rick: Was talking last night to my friend Blake who built the Lil Bastard. He'd built it intending to run the Lochsa but found it a wet ride on the Alberton Gorge. His comment wasn't "If you run the Lochsa..", it was "When you run the Lochsa...you'll want higher sides."
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Permalink Reply by Rick Newman on
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Absolutely! I really like floating the Main Salmon. We did a 13 day trip one summer.It was a wonderful experience. Not like the Grand Canyon but still wonderful! In March of that year another group and I floated the Lower Main to Heller Bar. Another group ran the Middle fork all the way to Corn Creek. We had a great year and ran some big water, spending many night in a great place.
I think your boat looks better with a wider beam.
Rick
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I love love love the Main.
I know I'm supposed to like the Middle Salmon more as a whitewater guy--I've kayaked it once and rafted it once, but I like the Main better. Have been fortunate to run it (rafts) in 2018 and 2019, and took my dory in 2020. Planning a high water (mid-June) Main-Lower for this year.
Shawn
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I released the spreader athwartships and let the sides flare out more.
More flare:
from the bow—I definitely need to spread the bow out more
Definitely like it more with the extra flare. I thought I had calculated it correctly to hit 60" wide (to fit in the bed of the pickup) and be the same width as the big boat, but it was too vertical-sided. It's now sprad to the angle as the big boat. Will definitely have to trim the middle or the entire side to keep it at 60" with more flare.
Everything moves. With a given panel shape, more flare also adds more rocker. If you spread the cheeks more, it adds a bit more bow rocker. This is at 7-8" of rocker bow and stern.
You can push/pull anything an inch or two and keep things fair. If you shove it more than that, you end up with a "hard spot" and will have a funny outward bump in your sheerline.
I don't know if "cheeky" is traditional or not in all Rogue boats. Definitely a GC dory thing, as McKenzie boats tend to have a smoother curve in plan view. Another point in the "everything moves" view: if you see an up-raked Scimitar curve to the bow, there's either a concave cut in the sheer line, or it's cheeky!
Interesting condition here. I put the ratchet strap on the top line to pull the sides out and help the rocker in the floor. Transom epoxy was not yet cured, so the top 1/3 popped the screws and then glued itself inboard about 1/2".https://www.mountainbuzz.com/attachments/1609772686973-png.61754/" class="bbImage ls-is-cached lazyloaded" data-zoom-target="1" data-url="" alt="61754" src="https://www.mountainbuzz.com/cdn-cgi/image/format=auto,onerror=redirect,width=1920,height=1920,fit=scale-down/https://www.mountainbuzz.com/attachments/1609772686973-png.61754/" />
I'll just run a saw down the top 1/3 of the joint to cut the epoxy and straighten it out after the floor is glassed and the rocker set. I only used epoxy and wood flour on the initial fillets. If I had used cabosil, the fillets would have been much, much harder!
Interesting that I used to try to hide my mistakes, now I can recognize them more quickly and will fix them so I'm not continually compensating for them later.
And you're going to make mistakes building boats. It's OK!Also did some intermediate fillets with 1/4" chopped glass fibers so I can pull the screws into the floor and do the big fillets and biax tape. Filleted up 2/3 of the transom so it will hold when I saw the top to correct the slip.
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(yesterday's pics were Day 4 Sat 11/2 and Day 5 Sun 11/3)
Day 6: floor glass. Cut the glass to fit
This is 51" wide glass. The floor is 36" wide. I first cut the glass about 43" wide so it will lap up 3" on each side. That left an 8" wide strip. That was cut in half to make the tape that went over the fillets. it's pretty hard to cut plain weave cloth into tape, but is REALLY easy to cut biax parallel to the stitching into tape, and biaxial is already...biaxial...so it forms really well into corners. I use all my biax scraps to make tape to glass in my bulkheads, too.
Folded it over and kept it in alignment to then apply thicker fillets
Fillets are a mixture of flour, epoxy, and chopped fiberglass. Add the chopped glass first so the epoxy saturates it, then add flour to thicken. Previous fillets were "peanut butter" consistency, these are more like "thick milkshake" consistency so there's some loose epoxy to bond to the glass fillets.
Cut biax tape to cover the fillets, wet it all out.Wet out the glass with epoxy and a squeegee. The initial coat takes roughly the same weight by volume of epoxy as the glass to be wet out.
In this case, 20oz/sq yard glass x 3 yards = 60 oz. of glass. I used about 60oz of epoxy (and 8oz more for the fillets)
A cube heater—on stilts do it doesn’t stick in the epoxy—provided overnight heat to cure the goo.
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Update time!
From late on Day 6, floor glass wet out and flow coated. Had a bit of a dry spot right of the heater where the tow didn't get completely saturated. Hit it with the heat gun, but the epoxy had already started to kick. I gave my previous US Composites more heat to saturate the glass. I can see I'll need to give the RAKA more patience, it will saturate on its own, accelerating it might be too fast for a good soak.Day 7: Bulkheads glassed (above)
Day 8: bulkheads installedChecking the fit. Center one dropped in. Front one took a lot of trimming.
Trim a tiny bit at a time!
This is one of my better ideas of late: HDPE strips clamped to the sides to align the bulkheads as the epoxy cured. Epoxy doesn’t stick to HDPE.
Did a quick scuff sand on the sides and bottom where the epoxy needed to bond. Brushed on unthickened epoxy, it flows better and will bond into the little scuffs. Then thickened epoxy (a little flour, a little kitty hair...runny milkshake consistency) on the edges of hte bulkhead. Worked great to drop the epoxied bulkheads into the slots rather than trying to align clamps with epoxy goo sliding all over.That’s a temp spreader above the forward bulkhead so there’s no pressure on the bulkhead or joints until the epoxy cures
Tonight I will do a thicker epoxy fillet with more chopped glass in the mix and then a ~3" wide biax tape fillet.
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Day 9: glass tape fillets on the bulkheads
I didn't calculate actually how much area that 2" biax tape actually takes up, especially on both sides of 2 bulkheads and under-mixed my epoxy. figured 4oz would do it. Ended up using 10!
My trick is to use about 1:1 epoxy by volume as the weight of the cloth.
If you're laying up 4sf of 20oz cloth:
20 oz/Sy is 20 oz/9sf, or about 2.2oz/sf. 2.2 x 4sf = 8.8oz
I'd mix 9oz, and with a 2:1 resin, that’s an easy 6 oz resin and 3 oz for hardener. I then use about 1/2 that on the first flow coat and 1/4 that amount on the 2nd flow coat.Sanded the rough spots this morning and added a flow coat. I'll start framing the decks this weekend.
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Looking good!
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Friday morning I put fill coats on the fillets.
Day 10:
This will be the new sheer (gunnel) line. 1.5" lower at the center of the boat. I think it's purty.
cutting decks. Stern deck. I will sit on this section of deck and there will be a hatch behind me. I measure the width at the front of the deck, the back of the deck, then take a batten to determine how much convex curve there is between the two. Scribe that on the plywood, and then cut about 1/4" outside the line. I then use an oscillating multitool to trim the high spots and "sneak up on" the line.
Then did the same for the aft deck. Didn't get a pic of the frame at the back of the center deck, will add one later.
Front bulkhead was a tad low so I added two more strips. Will glass them in with the deck.
And the foredeck.
Originally planned on an 18”x32” stern hatch. Would have been a 16”x30” opening. Too small for a 65qt cooler. Bumped it up to 20”x33”.
Front hatch will remain 18”x32"
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Day 11, Sunday January 10. yesterday was a crazy productive day. Worked 9 solid hours.
Hatch frames and lower lip support. Laminating everything rather than cutting from solid stock. Stronger laminated, plus using up scrap and making less sawdust.
I start by drilling a hole in the corner of where I'd marked the hatch on the deck to transfer that point to the bottom side of the deck.
First piece is a 3/4" tall x 1" wide "riser". Cut a piece to span across the width of the boat, miter the corners to match the side panels. Temp screw that to the deck. then two 18" or 20" long pieces for the risers at the sides of the hatch opening.
Then a 2.5" wide x 1/2" thick "platform" that the hatch lips will rest on. This will all get glassed on the bottom for tensile strength.
I'll then add the 3/4" chamfer "ramps" on the outsides of the frame to make it easy for the fiberglass to wrap up and over.
Working out the oarsmans footwell and side bulkheads. Using up meranti ply scrap from the big boat. I have enough material from my initial cutting plan...but those pieces are also large enough to be two more side panels for another small boat!!
And the spare oar slot.
Glassing the underside of the decks. I trim the glass 1” larger in all dimensions, fold the glass over, wet out half the wood, fold the glass over to expose the other half, wet that out, then spread epoxy in all the glass. Once the glass is wet out, it will appear hazy as there is air between the fibers and weave. Mix more epoxy, squeegee it on and make the glass shiny again. Within 8-12 hours (so the epoxy will chemically bond before it is fully cured) squeegee on at least one flow coat to fully fill the weave.Plain weave glass is all but transparent when wet out.
Glass on the underside of the decks provides tensile strength...so I can sit/step/sleep on them.
They got a quick fill coat this morning.
52sf of 8oz glass took right around 50oz of epoxy including what was used as glue to join the hatch risers and plates.
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Looking great! The energy of youth!
Rick Newman
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