[MT4Runner]

This place has been a little dry lately, and I'd begged the mods for a dory subforum and promised I'd post more build pics if dory threads weren't just scattered across the fora...
Contemplated this build 6 months ago, and learned a bunch from rowing the Lil' Bastard.

So here we are.

10'-6" LOA
60" beam
36" floor width
~23" deep at the oarlocks

One final 1:6 cardboard mockup:

Cut the plywood. One piece ripped diagonally lengthwise, the bow panels out of the width of another sheet.

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.

 

[class 3 felon]

Looks cool, can't wait to watch it progress

 

[MT4Runner]

Hope to bring it to the COWBF this fall!

 

[gnoble1]

Excited for this one! Can you explain again why you decided on 36" bottom vs 48"? Also, what thickness of wood for sides and bottom?
Cheers,
Greg

 

[MT4Runner]

Excellent question! I probably wouldn't have gone so narrow if I hadn't already felt it.
I want secondary stability more than initial stability, so I want more flare in the sides (secondary) than a wide floor (initial).

A wide floor tries to stay flat to the water's surface. Works GREAT when you're on flat water, but on the face of a wave, the entire boat tilts to match the face (or shoulder) of the wave. With flare, there's some happy medium. It feels slightly more "tippy" on flat water, but doesn't feel any more "tippy" in rough water, and with some "body English" you can highside and keep the boat a bit more upright.

And flared sides are a drier ride in confused waves. A vertical side (wide floors, Mckenzie drifters) will get "slapped" by a wave and the wave will splash in. Flare deflects the wave away and also deflects the boat up and over.

The Lil' Bastard has a 38" floor, similar length and width, and is reasonably stable!

And my big 17' GC dory has a 48" floor. I don't need that much width on a smaller boat. Both floor and oarlock width are scaled down 75% from the big boat.
Since I'll be primarily sitting and rowing whitewater and not standing and fishing, I don't want the initial.



1/4" floor, sides, and decks. Thinner than normal on the floor, but a weight-saving measure. Trying to keep it light enough to be loaded by one person into the back of a pickup.


Everything is a design compromise. Thanks again, good questions!

 

[Infidien]

Have you considered a layer of kevlar for that thin floor?

 

[MT4Runner]

Will get 2 layers 1208 biax inside and out.
Not specifically opposed to Kevlar, but it's tenacious enough that it's difficult to sand or cut cleanly when repairing.

Can't really have strong-light-inexpensive, so I went repairable instead of heavy.

 

[BGillespie]

How "long" is the scarf? Any more pics of the cutting jig?

 

[raymo]

I would of loved to have one of those! Can't wait to see it finish. I envy people with building skills like you and others on MB.

 

[MT4Runner]

How "long" is the scarf? Any more pics of the cutting jig?

2” in 1/4” ply, so 8:1


the scary jig:

 

[Spintowin]

BITCHIN!

 

[MT4Runner]

Day 3:
Sanding to show the grain, final cutting and fairing panels, glassing the inside faces.

The stain covered the grain a bit too much. Some quick work with 120 grit exposed the grain on the harder summer grain, the softer summer grain took the stain deeper and stayed gray.

Did a little creative sanding to get the grain to line up between the different panels

Planing the rolling bevel on the bowpost. 76° included angle at the base, 108° included angle at the top.

76° angle at the base

108° at the top where the panels flare out

 

[MT4Runner]

The chine (bottom) of the side panels has a flat spot

Planed out for a "fair" curve. Boats don't need to be straight, they need to be fair. A fair line is pleasing to the eye. No measurement tools were harmed or even touched in this step. haha

Top (sheer) cut out.

The sheer faired

Glass on the inside faces. Had some delamination in one spot, so it got the "ceiling press".

You may have noticed that I'm just using common exterior grade 1/4" AC douglas fir plywood. The glue is the same, and it's made in the same Roseburg, Oregon factory. The A face is the same quality as marine ply. The core isn't bad. The inside C face has the knots you can see...but everything visible on the inside will be painted.

With fiberglass inside and out, the wood has less need for strength, and it's actually more of a core material. If I were building a plank on frame boat, AA or AB or BS1088 Marine ply would be a MUST. If this were a customer boat and not my play boat, I'd also be using marine ply. And...it was available locally, the boat is a prototype, and not a Steinway piano...let's go boatin'!

I'm really shooting to get this in the water by about April to feel how it does in the water, and decide if the design is good or if it's back to Cardboard Aided Design!

 

[gnoble1]

Thanks for the detailed posts. Curious about the rolling bevel on the bowpost. Have built a two-transom buffalo boat as my first build but want the next one to more "traditional", with a bowpost.

What's the best resource you've found on the rolling bevel and is it just specific to the briggs? Was trying to research it in Roger's book but couldnt find a whole lot.

 

[MT4Runner]

Great question.
Really depends on your boat design.

Yes, the "cheeky" sheerline on the Briggs boats needs more than 90° included--so more than 45° on each side.

This is 54° on each side (or 90-54 = 36° angle cut when standing up on the table saw since you can't cut 54° on a table saw)


And the floor is a bit under 74°

So the rolling bevel is how you get between the two.

By cutting the whole thing at 54° on both sides and then paring down the back to (76°/2) = 38° we can keep the front face the same width..which will help for later gluing on the outer stem.
If I had cut it all at the narrower angle, the top front would get narrower when cutting in the flat angle. It seems like voodoo, and is easier done than said!

 

[MT4Runner]

Here's another sketch of the angle you'd cut. Note the front face stays equal width, and the back face gets narrow.
If you visualize the dashed line as what you will cut to, you can visualize that angled face rolling from one angle to the other..hence the rolling bevel.

 

[Pinner62]

Excellent post and effort. Look forward to seeing it complete and on the water. If I ever complete my full-size Briggs ( currently 75%) I should make one of these to run side by side with my Sportyak II.
Great work
Cheers

 

[MT4Runner]

Got pics of your project, @Pinner62 ?

Stitch and glue or ply on frame?

 

[Pinner62]

Got pics of your project, @Pinner62 ?

Stitch and glue or ply on frame?

Framed. I was at Brad Dimmock's workshop in Flag in February'18. It originally went to another participant. He wasn't able to finish it so I picked it up from him in Prescott. I've had it a year. I'll post some pics tomorrow. Looking forward to the sound of waves on the gunnels!

 

[MT4Runner]

Was that the one @MNichols was at?
Pat Clark's South Fork is the class boat from the 2017 class, IIRC. I'd have liked to take the class, but he was no longer doing them in late 2018, you must have broken the mold!

Post up a build thread, would love to follow along.