Plywood Canoe Concept - Birchbark Style

[flo-mo]

Brian,
thank you for posting these photos. Amazing resemblance to the shape of my canoe -- especially at the bow.

[keyhavenpotterer]

Ed has posted more pictures over on his Beale report thread

http://forum.woodenboat.com/showthre...51#post4564051

Brian

[flo-mo]

Upon request I added offsets for Gorewood 15-8, a version made of two 244 x 122 cm, 4 mm marine grade okoume plywood sheets (left click at the drawing for PDF-download):

[cracked lid]

Just noticed there is a German company which offers very nice canoes built exactly to the method that is the topic of this thread: Canadian Traditional Craft

Actually I am almost certain their Guron design (in the background of the photo) is an only slightly modified copy of my Gorewood 14 except for the more traditional approach of the execution.



I do not blame them for doing so, because by discussing the building method (which BTW is not my invention), providing the cut-pattern for free and elaborately documenting the build of my canoe it was my intention to motivate others to look into it, maybe improve and refine it, which they obviously did.

I only wish there was a hint where the inspiration and the cut pattern for the plywood came from which would have been nice.

I really despise when people don't give credit where it's due. It's not that hard to simply name and thank the person who's knowledge you are expropriating. When people make their work freely available to others it just means you don't have to pay them money for it. It doesn't mean you're excused from giving them credit and thanks.

If it was me, I would be getting in touch with them to call them out on it.

[flo-mo]

I really despise when people don't give credit where it's due. It's not that hard to simply name and thank the person who's knowledge you are expropriating. When people make their work freely available to others it just means you don't have to pay them money for it. It doesn't mean you're excused from giving them credit and thanks.

If it was me, I would be getting in touch with them to call them out on it.

They apologized and gave me proportionate credit after all so we are good -- no bad feelings.

[flo-mo]

After hearing from two ambitious builders who's attempts were sadly doomed to failure I am happy to present the to my knowledge first successfully built Gorewood 16 Canoe.


Pál from Hungary build a beautiful canoe and kindly gave me detailed information about his build and the materials he used.

Hull made of 4mm water and boil proof birch plywood

Inside of the hull sheathed with 163 g fiberglass cloth, gores reinforced with one strip of 180 g carbon kevlar tape, stems with two layers of 180g carbon kevlar bias tape

Outside of the hull sheathed with one layer of 180 g carbon kevlar hybrid fabric, covered by one layer of 163 g fiberglass cloth, stems covered by three layers of 180g and one layer of 220g carbon kevlar bias tape

For his home water he needs a tough canoe that can take some abuse so the weight of his boat is more on the heavy side.

Bare hull: 15.8 kg (35.1 lbs)
Finished canoe: 29.2 kg (64.9 kg)

The result of his effort is a stunning canoe and I am glad he likes the performance of the boat.


From Pál's facebook page: https://www.facebook.com/pal.mezes?h...wser&fref=pymk


Photos of the build: https://plus.google.com/photos/10096...88925852619409

[flo-mo]

Pál's home water:

[Daniel Noyes]

wow looks great. very nice design.

[flo-mo]

What a lovely photo of Pál Mézes' Gorewood 16:

[flo-mo]

IMPORTANT MESSAGE:


For all who fancy to build one of my Gorewood designs please be sure to take a close look at my thread in the Building/Repair section: Flirting with disaster - build of a revised Gorewood 16' Canoe - no happy end

[alexau]

dunno . . . where is here? Craft stores is a dead on recommendation -- I get mine at Hobby Lobby, but Michaels or JoAnnes fabrics should have something similar in their wood section. I wonder if pressboard off of the old style clipboards would work? Its pretty sturdy and thin . . . might be a touch heavy . . . If you cant find it there, before you order the plywood online, you might just want to order the laser cut ones from the FT store. Theyre not too pricey, and it supports the show. just a suggestion . . .

[Ppaul]

Upon request I added offsets for Gorewood 15-8, a version made of two 244 x 122 cm, 4 mm marine grade okoume plywood sheets (left click at the drawing for PDF-download):

Hi,

I write from France, where I spend as much time as I can tripping on the local rivers.

Most of my trips are up river, and other than poling, I tend to have a lot of portages over dams and all sort of obstacles. Poling requires more stability than normal paddling, but I still need a fast hull to paddle against the current. My current mistral 17.5 is good (stable and fast), but too heavy and cumbersome on the portages and windage is a real issue (I travel very light). Mostly I-II rivers, big ones, small forgotten ones…

Can anyone help me find the hull specs for the 15-8. I'm trying to adapt the size and shape to my tripping style, but is difficult to modify on my CAD with out the target beam, center depth, or an idea about the displacement.

I'm aiming for 14.5/15 for a 33" beam, "flatfish" stern, and some bow rocker. 3mm ply, fiberglass both sides, and keeping the rest as light and simple as possible.

I've made a SOF, but it was impossible to pole. In France red cedar for strips is to expensive to end up scrapping the shallows. I was about to ahead with a S&G canoe (modified 15 prospector), when I found this very elegant technique that I find particularly suited to make a canoe. The resulting shapes are amazing! Thanks very much flo-mo, for the plans, and the detailed explanations: I can't wait to get started!

[flo-mo]

Hi Ppaul,

estimated specifications for the Gorewood 15-8 Canoe:

Length: 478 cm (15’ 8")
Beam: 86 cm (34”)
Displacement: 135/225 kg (300/500 lbs)
Draft: 9.5/13.5 cm (3 3/4” / 5")
Approx. Bare Boat Weight: 25 kg (56 lbs)
Midship Depth: 34.5 cm (13 5/8")

Cheers
Stefan

[flo-mo]

Gorewood goes everywhere!

Croatia:


Slovenia:


Bath:


Phuket:


The builder from Thailand also makes exquisite models:


The last three photos are from these two facebook pages:
https://www.facebook.com/pg/bristolc...70754096890108
https://www.facebook.com/saychonsahe...=pb_friends_tl

[johngsandusky]

Nice pics! Beautiful and creative canoes throughout this thread. Makes me dream of building one, until I remember that I already have a lightweight wooden canoe in the basement. Plus plenty of work to do on the big boat, the house, the car...
Thanks for sharing!

[aerofan]

Hello builders...


Question for those who have attempted or completed this build. My closest marine grade plywood supplier does not supply the 4mm okoume thickness. they have 3mm and then jump up to 6mm. Is there any reason this cannot be completed in the 3mm and then reinforced well with fabric? I realize that an early build ended in failure. Was that attributed to the thickness of plywood or the type/characteristics of the plywood?

thanks

happy to see the thread reborn

J

[flo-mo]

Hi Aerofan,

The reason why my earlier build failed was most likely because the face veneers of my 4 mm okoume plywood were to thin (only about 1 mm) respectively the core veneer was to thick (2 mm). You want plywood with about even thickness of all three veneers. I did not have any problems with my second attempt when I used plywood which almost met this requirement.

There is a builder from Slovenia who used 3 mm for his Gorewood 15-8 which worked out very well.

FOT39E.jpg

He strengthened the hull with an extra layer of heavier cloth. See posts #53 to #60 of this thread: http://forum.woodenboat.com/showthre...-attempt/page2

[flo-mo]

I found an excellent Gorewood canoe on this Russian boat forum: https://forum.katera.ru/index.php?/t...kanoe/page-283

Based on the Gorewood 14 a builder from Minsk, Belarus created a design to fit his own needs (LOA = 15', beam = 30", midship depth = 12"). The result is a stunning canoe with lovely crafted details.














More photos at his insta: https://www.instagram.com/boats_oars_and_paddles/

[flo-mo]

Another beauty by the same builder:

[johngsandusky]

Beautiful!

[MN Dave]

Hello builders...


Question for those who have attempted or completed this build. My closest marine grade plywood supplier does not supply the 4mm okoume thickness. they have 3mm and then jump up to 6mm. Is there any reason this cannot be completed in the 3mm and then reinforced well with fabric? I realize that an early build ended in failure. Was that attributed to the thickness of plywood or the type/characteristics of the plywood?

thanks

happy to see the thread reborn

J

3mm okoume is fine. Stefan can't get it in Vienna, so he is stuck with 4mm poplar. After 20 years, my 3mm canoe is holding up well.

The inspiration for these boats was the tortured plywood designs from Stillwater Canoes in Silver Springs MD (Sadly no longer around). Stillwater had designs for 11 and 16 foot tortured ply canoes, both of which used 3mm marine okoume plywood. I built a Stillwater Dusk with 3mm okoume from Boulter in Boston about 20 years ago. It has one layer of 6 oz glass on the outside. It also has a 'shear streak' that is a 3-4" wide doubler at the shear.

I built a longer version of the dusk using the same forms a few years ago. I am afraid that the workmanship doesn't compare to Stefan's very well.
Canoe.jpg
Since it was longer, I didn't know where to locate the darts. I just wrapped the plywood around the forms and looked at where it wanted to buckle. You can see the gap between the batten (looks like a gunnel) and the plywood in the picture. I cut three darts where it looked like the plywood was under the most stress on each of the four panels.
Attachment 25048
There was some tendency to crack at the end of the darts. I drilled a 6mm hole at the point of the darts and added a backer on the inside. The backer was intended to smooth the curvature and reinforce the darts. I have no idea if it really helped, but they did make sanding the inside more difficult. The backers can be seen in the first picture.
Attachment 25049
Clamping backers.
Picture4.jpg

Clamping the shear doubler:
Picture2.jpg
The Stillwater boats are built in halves and joined to set the rocker.

[flo-mo]

Dave,

Thank you for adding the photos of your canoe. I was always interested to see a photo of one of the Stillwater Canoes. They look very nice indeed.

The idea of the construction of the Stillwater Canoes was definitely an important influence for me to come up with my own take on this subject. So thank you again for exposing me to this idea.

The most important influence for all of us who engage in this kind of design of course goes back to the birch bark canoe and the wonderful illustrations by Edwin Tappan Adney in this lovely book: http://www.gutenberg.org/files/50828...-h.htm#Page_30

These drawings show almost all you need to know about the principle:

i046a.jpg

i046b.jpg

i047a.jpg

[aerofan]

Thank you for the feedback. I appreciate you answering my concerns about the 3mm ply. Very good to know your builds are holding up well.

[flo-mo]

About a month ago I finished another Gorewood Canoe. 14 ft long like the very first one that I built, but with more freeboard and slightly heavier (16.5 kg/37 lbs) because this time I used 4 mm instead of 3 mm poplar plywood.


Gorewood 14 FB+ (Photos of the build: https://photos.app.goo.gl/dPdZLvmggTVNqF4a9)

[MN Dave]

You do such nice work! The boat is beautiful.

One of the pictures in my earlier post #91 is missing, and it illustrates one of the more important aspects of the seat of the pants approach to building a tortured plywood canoe. I don't have the software to model the dart locations, so I wrap the skin around a form and look for the places it buckles. This is the missing image (Attachment 25048)
Dusk_Buckle.jpg

[amish rob]

I found an excellent Gorewood canoe on this Russian boat forum: https://forum.katera.ru/index.php?/t...kanoe/page-283

Based on the Gorewood 14 a builder from Minsk, Belarus created a design to fit his own needs (LOA = 15', beam = 30", midship depth = 12"). The result is a stunning canoe with lovely crafted details.














More photos at his insta: https://www.instagram.com/boats_oars_and_paddles/

Dang. That looks amazing.

Peace,
Robert

[John Meachen]

Very pretty canoe.I may just need something similar in my life.

[Matt young]

Nice! Were the ribs added after the hull was stitched together?

[SHClark]

Have you considered doing this the other way.
Cutting vertical/ athwartship slots in the middle of the panels to allow the turn of the bilge to grow instead putting tucks in at the sheer.
SHC

[MN Dave]

Nice! Were the ribs added after the hull was stitched together?

The first picture in the Russian build shows the hull assembled without ribs. Stefan doesn't use ribs. The ribs look like they had some steam bending problems. IMHO, the ribs are more decorative than functional.

As I typed that,I was thinking that it is too bad you can't get paulonia plywood, which would be lighter AND rot resistant. So I googled it and --
new-paulownia-marine-plywood

[Matt young]

Got it thanks! I appreciate that. Yeah I know he doesn’t use the ribs on his boats. That one being built by someone else. The more I thought about it I realized my question was a little silly. Maybe the ribs are a bit of belts and braces, someone wanting to be safe covering up the cuts?

[ulav8r]

The first picture in the Russian build shows the hull assembled without ribs. Stefan doesn't use ribs. The ribs look like they had some steam bending problems. IMHO, the ribs are more decorative than functional.

As I typed that,I was thinking that it is too bad you can't get paulonia plywood, which would be lighter AND rot resistant. So I googled it and --
new-paulownia-marine-plywood

No special orders. Paulownia marine plywood is available to us in limited quantities and we do our best to keep it in stock at our facility.
Please call or email with questions.
Update March 11, 2019: This item is out of stock and unavailable. Our usual supplier is also out of stock. We are working on locating a new supplier.

https://goosebaylumber.net/wood-prod...lownia-plywood

[flo-mo]

I had a little chat on Instagram with Vadim from Belarus, the builder of three exquisite Gorewood canoes, regarding his building procedure (https://www.instagram.com/p/By4akXkoeLR/).

• flo.mo_boats
  
  @boats_oars_and_paddles I am wondering if you sheath the outside of your canoes with glass cloth or do you simply rely on the strength of the ribs to connect the hull at the gores? Soon I will start the build of a new canoe using ribs and no glass cloth for the first time. So I am curious about your building procedure and your experience regarding the durability of your canoes.
• 
  
  • boats_oars_and_paddles
    
    @flo.mo_boats Hi, Stefan! I do not have to often and long carry my canoe on the shoulders. But often boats get hit hard when in contact with flooded trees and stones. I always use fiberglass inside and outside the boat hull. The ribs are glued on top of the fiberglass.
  • 
    boats_oars_and_paddles
    
    @flo.mo_boats Additional 1.5-2 kg of weight does not matter to me when it comes to extra strength. For the ribs I used a 2.5mm thick ash veneer. I just had no other. I think that 1.5mm thickness would be sufficient. And thus it is possible to reduce the final weight of the boat.
  • 
    flo.mo_boats
    
    @boats_oars_and_paddlesHi Vadim, thank you so much for taking the time to answer my questions -- your considerations make perfect sense. As you mentioned weight -- do you know the weight of your 14', 15' and 16' Gorewood canoes? My best wishes to you, Stefan
  • 
    boats_oars_and_paddles
    
    @flo.mo_boats Hi, Stefan. 14 foot canoe weighs 21kg, 15 foot weighs 24.5 kg. This canoe is laminated with fiberglass 230g / m2 inside and out. An overlap of 30 cm of keel is also made. 16 foot was not possible to weigh now. I will do it later.
  • 
    flo.mo_boats
    
    @boats_oars_and_paddlesThank you for the information

Vadim's 14, 15 and 16 Gorewood canoes:







Not only is Vadim an excellent boat builder, but he and his wife are also passionate canoeists. Recently they participated with his newly built Gorewood 16 (Crazy Otter) in a 60 km paddling-marathon on Moskva river. Their finishing time is 6:29 h -- quite remarkable as the river current is seemingly low.

Photo source: https://photos.app.goo.gl/LuKkiBpRvf6Z3vAb7

[MN Dave]

Have you considered doing this the other way.
Cutting vertical/ athwartship slots in the middle of the panels to allow the turn of the bilge to grow instead putting tucks in at the sheer.
SHC

The cuts at the sheer remove a narrow triangle of material and close up when the panel is bent to shape. They are only about 6" deep. If you were to cut athwartships, the cut would have to run all the way across the bottom and would open up as the panel was bent. It would be impossible to control the shape without forms and a strongback. Stefan's method doesn't require forms. The downside in my opinion is that the rocker is difficult to form.

The Stillwater canoes were built in two parts on two station forms on a strongback and then the halves were joined at the center. some material was removed at the gunnel to produce some rocker and maintain a reasonably narrow joint.

[SHClark]

I understand how the darts work. It’s pretty obvious to anyone who h as ever tried to compound bend plywood.
My idea comes from sailmaking. Assume you want to tighten the leech, you could open the seams and increase the overlap. Akin to taking the gore cuts. The alternative is to split the seam in the middle and stitch it back together with less overlap. Letting the middle out rather than pulling the edges in. Some sailmakers have done shocking things with knives and sail repair tape on the way to the starting line.
I was thinking that the slots would end up being 6” or so every foot. They wouldn’t have to cross the centerline, just provide enough relief for the center of the panels to stretch enough to prevent the edges from buckling.
It should come to the same thing.
I have built more than a few tortured ply boats, I didn’t mean any offense.
SHC