Plywood canoe

The question is why bother. If they didnt form part of the build, then retro-fitting them will be a nuisance, creating extra weight and possible voids when you cant fit it totally flush.

Once again - perhaps making work unnecessarily. If you want to avoid the visual effect of layers of glass on the outside, you only need to fillet the inside the join at the stern and bow, and lay a few layers of glass on the inside. This will be plenty strong, and not create any visual fasteners.

The neatest bow and stern finish I have seen is the one that the PT Skiff designer uses. He laminates about 8 layers of 6 oz glass into a sort of batten, then bandsaws them to about 10mm strips. He then epoxies them around the bow profile, epoxying them on with tape to hold them in place. Then he sands them to proper shape and puts a layer of epoxy over the whole hull. It provides a good looking protection strip.

 

The idea for the stem above deck level is to have something secure to locate the outboard motor bracket.

The tie holes need filling anyway, so little effort involved in making "epoxy rivets".
When there are so few holes it won't take long to make best use of them.

 

Seems like the only thing holding the planks together at the bow is the glass cloth. Even wrapped around from both sides forming a double layer it doesn't sound like enough to resist an argument with a rock. I believe most builders that do not use a wood inner stem add several layers of glass on the inside. Some folk use a poured epoxy inner stem but that is rather brittle IMHO, heavy too.

A brass stem band on the outside would add dent-resistance and - if polished - would also look nice. If you do that give it a couple of coats of varnish though; mine has tarnished.

 

Would you run the brass band the entire length of the canoe? Or just at the bow?

And would you place it over a wood piece? Or, just use a strap?

 

- each to his or her own taste, but I can only get it in 48 inch (1.2 m) lengths - and it's surprisingly heavy.


QUOTE=El_Guero;601460] . . . And would you place it over a wood piece? Or, just use a strap?[/QUOTE]

- it's usually fastened with bronze or brass screws about every 6 inches (15 cm) driven into a wood stem. It's available pre-drilled - it looks awful if the screwholes are off-center.

If there is no wooden stem perhaps machine screws and nuts could be used. If they are to be driven into solid epoxy, bronze would be needed. I wouldn't recommend stainless steel screws - ugly and asking for corrosion.

 

Sounds beautiful.

Yes, SS and Bronze is like using Titanium with anything else, you are asking for corrosion.

I really do want to build a jet kayak ....

I have been thinking about white/or maybe a light wood veneer from the gunwale down. And a combination of Ebony and Australian lace in strips for the deck and covers .... The gunwale would need to be Ebony, I think ....

I KNOW it is heavy, but it shines when burnished up ....

And I wish someone harvested South Texas Ebony ....

Brass or Bronze would really highlight ....

 

I stopped work for a month in the run up to and beyond Christmas/New Year. Restarted about 10 days ago which coincided with the weather turning cold, about freezing most of the time with some snow. The temperature inside the garage has been around 10C.

Although some of what I have done has been unorthodox, I decided to follow the plans for the stem and stern and use filled epoxy and tape inside and out.
To roughen up the West SIX10 and epoxy on the inside of the stem and chines I used a Dremel type bit in a cordless screwdriver/drill. It works much better with the slow speed and high torque.
There will be a compartment each end of the boat so as practice I filleted and taped the chines where they will be hidden.
To speed up the curing I used an old blower heater with a built in thermostat and an insulation board to keep the heat in, it runs for a minute every 10 minutes.
I cut out the frames so that the chines can be filleted and taped with the frames in place.
It is convenient for me to prime, fillet and tape as separate operations spread through the day. Not so much wet on wet as wet on tacky. I find it easier as the fillet is not sliding about on fresh epoxy and the tape sticks firmly so does not move when wetting out.
When mixing the epoxy hardener and fillers I put some warm water in a basin then float the mixing bowl in it to gently warm the epoxy/filler up making the mix runny and easier to mix and work with. When it goes on the cool wood it stiffens and so far there has not been a problem with sagging.
My plan is to fillet and tape the lower chines, fit the outer gunwales then fillet and tape the top chine.

 

Nice.

 

I filleted and taped the lower inside chines, then turned the boat over and taped the ends and the lowest outside chines. I applied some Q cells and epoxy mix to shape the ends, more needed later.
I am changing the sheer line from the original design, dropping the ends and raising the middle. I looked at a number of sheer lines I liked and did screen prints of them, then measured the offset at 1 foot intervals and tried to see if there was a formula, as it is not possible to get far enough away from the boat to do it by eye. As it turned out the designer's shape and the one I liked best were both parabolic although the designer's one had an extra lift at the end.
The formula I used was y=2x^2 where y is in mm and x is in feet
I used a laser level to position curved wood blocks at 1 foot centres which were hot glued and screwed above the line of the sheer.

I set up a rig for steaming the gunnels. It consists of square rainwater pipes supported on ply and hung from the ceiling with string. The steam was provided by a wallpaper stripper connected at the middle. It took some adjustment to get the same amount of steam coming out each end. I am a hoarder so had the old RWPs and offcuts of the new ones available, which luckily slid inside each other making joining easy.
I tied small blocks of wood at intervals along the gunnel to keep it off the bottom of the pipe and covered the pipe with fibreglass insulation.
After an hour I removed the insulation, turned off the steam, split the pipes in the middle, supported one section, cut its strings and withdrew the pipe and supported the gunnel with large paper clips attached to the ceiling. The front section went out the garage door and the rear section through the window. I then clamped the gunnel to the boat, snipping off the small wooden blocks as I went.
To do the next one, initially thought I would have to turn the boat around as the fixed window would be in the way. Instead I moved the gunnel to the other side after a couple of days. Obviously the boat is perfectly symmetrical so will fit on either side
While free it sprang back to about half way between straight and the fully bent shape.
My neighbour helped when clamping the second gunnel which made things less hectic.

 

I have now glued on the outer gunwales.
The manual showed the glue being added to the gunwale but I did not fancy handling a 16' long piece of thin wood with glue on one face
Instead I masked above and below the gunwale on the boat and on 3 sides of the gunwale. Primed the boat and gunwale with epoxy and later put epoxy thickened with microfibres on the boat, then clamped on the gunwale.
At the ends, I hot glued on wedges to give parallel faces for the clamp across the 2 ends of the gunwales and an extra vertical clamp to get the end of the gunwale to the right height.
The gunwales were supported from the ceiling while priming, ready for clamping.
The shopping bags are to protect the clamps I borrowed from a neighbour.

 

In between clamping on the gunnels and glueing them on I had epoxied the butt strap onto the central join in the flat bottom.
I also filleted and taped the top inside chine. Previously I had been laying wet on tacky but this time did wet on wet which was easier to position the tape.

I temporarily took out the frames to see how the boat was looking.

I squared off where the gunnels meet and epoxied on some tape. I shall be making laminated cork bumpers to cover the ends.

I made a start cutting out the bulkheads for the end compartments. There was a recent thread started by Troy on tick/joggle sticks which was timely. I used sticks hot glued to some ply to get the shape and roughly cut a piece of ply, then used it to glue strips on, to match the planks on the hull. I think this second method was suggested by rwatson some months ago. With having lumpy tape and epoxy on the chines there are not sharp corners to work from, so had to shave off some wood where the tapes stick up.

 

I know how you feel about handling long strips of wood with glue on them. My trick for gluing a gunnel is to clamp it on dry, get it in exactly the right position, unclamp half of it then glue and reclamp, and move on to the other end. Intellectually satisfying and totally non-scary!

 

I pretty much do the same with long floppy pieces. I prime coat with epoxy, let the epoxy cure green, clamp or mechanically fasten in the middle then thickened epoxy coat and clamp the rest.

Dowels are also a useful trick on some pieces. Epoxy is slippery stuff.

 

Thank you AK and Michael, I will try that when fitting the inwales.

I have been working on two aspects; the inwales and a frame across the middle of the boat.

The inwales are to be "scuppered", not for drainage but to have attachment points and improve the stiffness.
The sections of the inwale at each end where there will be compartments are continuous and I steamed them and bent them on a board in a horizontal direction as clamping them straight on, the edge of the boat was being flattened out. (see last photo)

I over bent them by more than twice the required curve and when released was roughly correct.
A problem occurred getting them to follow the vertical curve of the sheer so I re-steamed them and unfortunately lost some of the original horizontal bend then clamped them to the sheer with more than double the required vertical curve.

The ends will have a stem (see first photo ) that the inwales meet at a vertical and horizontal angle. I had a few goes at getting it right, in the end I clamped a batten on to the frame and nose and used it as a guide for the thin bladed pull saw.

Later I glued them on.


The frame for the middle started with plywood glued back to back then filleted and glassed into position with 2 layers of tape each side, then added lengths of Douglas fir 19 x 25 mm to create the full frame.

When planning this project I was struck by the number of canoes that looked inconvenient to use, thwarts that got in the way or trying to use a 2 person canoe alone made the trim wrong, also for sailing, fixed seating was a problem.

My solution is to have a basic shell, no permanent seating or thwarts, this also keeps the weight down for car-topping.

Depending whether I am just rowing or have the electric trolling motor or for sailing I shall make seating to suit each use and any strengthening for mast supports, leeboards and rudders etc. will be fitted when needed.

 

I had noticed the 'wales were a lot thicker on your boat than on my canoes and had wondered about that. I'm not surprised you had some challenges fitting them. I realize now it's to get adequate stiffness without a thwart. I built one of my canoes without a thwart several years ago, but in that case the reason was to make a design that could be stacked for transport.

Later I just made the thwart removable. The thwart is important for car-topping as well as paddling, as it prevents the gunnels spreading apart under the pressure of straps.