In which a canoe is built, its progress described and photographed.

Friday, December 28, 2007

7. Choosing wood for the strips

Over Christ Mass, I've been researching the wood I will use for strips. As usual, the Wooden Boat Forum was very helpful. Based on their suggestions I came up with the following priorities.
  1. Do not use the following:
    • very heavy or weak wood
    • highly resinous wood
  2. Preferable qualities
    • Clear (or close to it)
    • Long and straight
    • Workable
    • Strength to weight ratio
  3. My needs
    • Not too expensive
    • Available in central New York state
Everyone seems to agree that Western Red Cedar fits these priorities most completely. Many other woods were suggested, but I can get WRC and it is within my budget.

The best quote I have found for WRC is $0.79 / lin. ft. or, for my project, about $90.

I hope to buy the cedar early next week. I'll either buy my dad a thin-kerf blade for his table saw, or try to use our neighbor's bandsaw (which I hear is pretty nice, with a good wide band)

Sunday, December 9, 2007

6. Laminating the Inner Stems

Have you ever heard the phrase "from stem to stern"? How about "stem the tide"? Well, both phrases stem from a boat's stem. (sorry, I couldn't resist) To "stem the tide" is to sail fast enough to make forward progress against a tide.

On a boat the stem is the foreward edge of the bow. A canoe has a "point" at both ends, and so has a stem in the bow and in the stern.

Traditionally, the stem of a wooden boat would be made from one piece, but I will laminate mine from 1/8" oak strips my dad had sitting around from about 20 years ago. (see below and right) Oak seems like a good choice because it is strong and attractive. The author of the wooden boat article chose cedar, but leaves the choice up to the reader.

The author recommends using a waterproof glue, like polyurethane glue. Gorilla Glue is a common brand here in the US.

The strips will be clamped to the stem forms. I have cut 2" holes to accommodate the clamps, and taped the edge of the form with masking tape to protect it from the glue.

Gluing six 1/8" strips gives me a 3/4" thick stem. Use disposable gloves for this! You'll be glad you did. With the strips glued together, but not yet set up, I bent them around the stem form, and clamped them down. The strips complained a little bit as I did this, but I don't see any cracks, and I think it'll be OK.

Unfortunately, I only have enough clamps to do one stem at a time, so I'm taking a break while the glue sets and posting this.

5. Mounting the Forms on the Strongback

Yay! I have finished mounting the forms on the strongback.

The forms are attached to 2x3 blocks, which are attached to the top of the strongback. There are two forms not shown in this picture; the most forward and the most aft; the stem forms.

Even though I did my best to level the strongback, I still needed to level the forms as I installed them.

This I did by putting in one screw to pivot on, and holding the level on the center line while adjusting a shim.

The clamp is just there to hold the form fast to its station while putting in the first screw.

You can see the shim behind my left hand.

The view out the window is Cayuga Lake.

It's cold, and it's a little ways out of town (Ithaca) but it has been a wonderful apartment for three guys who like boats.

Finally, when all the forms are mounted, I can take a step back and admire the shape of the canoe.

You can see that I tried to line up the center lines for the picture, but a few forms are not perfectly lined up.

They're not too far off though, and I may leave it all as-is.

After all, this is the first boat I've ever built, and I'm not trying for perfection.

So far, I have probably spent about 20 hours on this project.

Next: Laminating the Inner Stems

4. Building the Strongback

To provide a stable, level platform for the forms, I built a strongback of 1/2" plywood and 1x2 furing strips in the form of a box beam. The box beam is supposed to be easy to build square and level.

Unfortunately, my plywood got rained on, and took on a warp, so my end result was not perfectly level. To fix this, I added an 8" strip of MDF left over from the forms, and shimmed it level.

Also, the porch I'm working on does not have a level floor, so that complicates things. Ideally, I would like a woodshop to work in, but for now I share a 3 bedroom apartment so I am happy to have any working space at all.

The porch is well lit during the day, and though unheated, it is enclosed, which will help when I apply epoxy (Epoxy needs a minimum temperature to cure).

3. Cutting Out the Forms

I have finished cutting out the forms, and there is a certain satisfaction in seeing them stacked, showing the eventual shape of the canoe.

After roughly cutting the forms out of the 4x8 sheet of MDF with my little cheap jigsaw, I took them to my dad's woodshop and used the bandsaw to finish them. If I could do it again, I would nail each primary form (the one I drew) to its blank, and cut them both at the same time. (Instead, I cut out the primaries, and then traced them onto the blanks, which took longer, and was less precise.)

Saturday, December 1, 2007

2. Drawing the Forms

Nymph is a strip-built canoe. This means that thin wooden strips will be laid over temporary forms. The strips will run the length of the canoe. When all the strips are in place, they will be covered in fiberglass and epoxy, for strength, and the temporary forms will be removed.

Historically, before fiberglass and epoxy became standard, wooden ribs, perpendicular to the strips, provided the strength. (see below)

Sairy Gamp 1883 by J. Henry Rushton
(technically lapstrake, not strip-built? but shows ribs)

The first step I will take is to build the temporary forms. The forms are cross-sections of the canoe. Taking the table of offsets from the Wooden Boat article, I draw a grid, like graph paper, onto 3/4" MDF fiberboard. Then I carefully plot the "data points" from the table of offsets onto the grid. Finally, I play connect the dots. It's like drawing a graph back in high school (middle school?)

The horizontal lines of the grid are called waterlines, and the vertical lines are called buttock lines.

This process is a simplified form of lofting.

The form I am drawing in the picture is form #0, the middle form.
Nymph is symmetrical, so I will make one copy of form #0, but I will make two copies of every other form, saving a lot of drawing. That's good, because the drawing is pretty slow.

My roomate had an aluminum T-square, which is very useful for drawing the grid.

Next: Cutting out the forms
Then: Building the strongback

Update: 3 of 7 forms drawn (12/3)
Update: 5 of 7 forms drawn (12/4)

1. The Canoe

The canoe is Nymph, designed by Nick Schade. It's design and construction are outlined in Wooden Boat no. 199. It is the first boat I've ever built. It will be the second boat I've ever owned.

My name is Jared, and I live in central New York state, USA.

Nymph is a lightweight wooden double-paddle canoe (think "kayak paddle"). Her design incorporates "tumblehome" (the sides curve in a bit at the top) to make paddling easier. The dark strip (walnut) in the picture to the right highlights the tumblehome.

Construction is strip-built, plus fiberglass and epoxy.

The picture is from the Wooden Boat article, and I use it here in the spirit of fair use.