Making Sawdust

20.13 in Boat Plans, boatbuilding, for, how, make, making, man, not, old, organization, questions, sawdust, suck, the, to

The whole process of building a boat involves cutting a lot of lumber, but at the beginning there were whole days of doing nothing but.

The plans called for kiln-dried or air-dried lumber of no more than 12% moisture.  I live in the hills of Northern California which at times is like living in a rain forest, so that seemed unlikely.  In terms of what species of lumber, what tree: there was a long list of species that would work and a long list of ones that would not.  Doug fir is the most commonly available light, strong construction lumber on the west coast and was on the okay list.  So this began with a treasure hunt to find just the right lumber to build the frame of the boat that would not be ridiculously expensive.

The reason for the specificity of tree and moisture content of the lumber had to do with the epoxy that would be used to bind it all together.  Every joint and every plywood seam and every place where plywood contacts a member gets epoxied. Epoxy wont bind well if the lumber is green, wet, or is of a species of wood that is high in natural oils.

After a little research, I found that our local lumber company, what used to be San Lorenzo Lumber (now ProBuilt), had in one of their yards kiln-dried Doug Fir that was not much more expensive than the green wood they normally sell for construction.  Sweet.  Three hundred dollars of wood later, my old work truck was loaded with boat lumber and headed up to E. Zayante where the boat was being built.

Generally, I had big long 16 and 20 foot 2x4 lengths.  The boat has a 20 foot long top deck, and because of the rake at the ends, is 16 foot along the bottom.  There are also 8 foot long beams across the boat ("athwartship" in boatbuilding-speak) and a bunch of little stuff that would be ends, posts, etcetera. 

But the plans called for ripping every piece to some new width, some 3 inches wide some 2-1/2.  A finish 2x4 from the lumberyard is actually 3-1/2 x 1-1/2 with smooth rounded corners.  Instead of taking a half inch off of a side to make a 3 inch thick piece, the plans called for taking off a 1/4 inch on either side.  The reason for this is sensible:  Cutting off the rounded edges of the lumber makes a better joint when it is epoxied.

So we spent a whole day feeding 16 and 20 foot long lengths of lumber into the tablesaw... twice. We made lots and lots of sawdust.

Then we cut a bunch of stuff to length, labeled it, and voila.  At the end of the day, we had a pile of lumber that we intended to turn into a boat.

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Keel and Skeg Stringers

10.18 in and, Boat Plans, epoxy, is, keel, making, sawdust, skeg, stressful, stringers

It most conventionally built wooden boats, the frames refer to what you might think of as the "ribs" of the boat running across ways (thats "athwartship," to you, matey!).  In the Glen-L Waterlodge, the framing members run longitudinally and are called stringers.

So building the boat frame means assembling the individual stringers and then tying them together with various cross beams. 

There were five stringers total.  Two side stringers, one keel stringer in the middle, and two "skeg stringers" between the keel and the side stringers. While the plans are relatively straightforward about building the stringers, there are lots of pesky details to consider, notches for cross beams, plywood reinforcement, butt blocks to make sure the plywood on the side stringers didnt leak, and a subtle curve to the deck that will sit on top of the stringers.

The keel stringer used big pieces of plywood to structurally reinforce the member and did not have overlapping two-by pieces.  The skeg stringers did have overlapping two-by pieces but no reinforcing plywood. The result will be two big storage bulkheads under the decks on either side of the boat.

The side stringers of course had plywood that covered the outside surface of the boat and no overlapping two-by pieces.  Well talk about these and their butt blocks in the next build day entry.

The notches for the cross beams were easy, though we still forgot a few and had to cut them out of the already assembled stringers.  The porch deck beam notches were not really dimensioned properly on the plans and so we had to do a little improvisation later. 

We built the stringers on the asphalt floor of the barn.  It was flatish and shaded, so we didnt bake as we fretted over the details of our new stringers.

One challenge we faced was making sure that each member we built matched all the others. The plans suggested literally building them one on top of another.  This didnt seem that practical, so we hit on a solution:  Using the plywood already cut to shape for the side stringers as a pattern for our other stringers.  That way wed know that all the angles would be correct and all the pieces of each member would be in the right place.

We used what we called temporary butt blocks just to hold the side plywood in place while we were using it as a pattern.

So in these photos, you can see the side plywood under our stringers as a pattern. 

From left to right: keel stringer, starboard skeg stringer, and port skeg stringer.

So for each stringer, the process was more or less:  Lay out the pieces for fit on our plywood pattern; put wax paper under anything we didnt want to be permanently adhered to anything below, temporarily screw down, as necessary; apply a thin coat of epoxy to both surfaces of every joint; apply a thickened coat of epoxy to one side of every joint; and finally fasten together all joints with stainless steel screws.

 

After the epoxy on the stringers sets, we could put the stringers on the building form. 

Exciting!  It is looking more boat-like every day. These incremental changes are probably pretty minor looking to other folks, and the progress may seem pretty slow.  But for us, it is crazy.  Look we had a pile of lumber!  Now we have this boat(ish) thing!  Amazing!

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Angles and Precision

02.37 in and, angles, Boat Plans, build, building, day, first, form, making, precision, sawdust

I have experience in the housebuilding, construction world.  I used to joke with my workers when theyd talk about measurement in sixteenths.  "Sixteenths?  I didnt know they made fractions smaller than eighths."  And in homebuilding, unless you are a finish carpenter, there is seldom need to take such fine measurements.

Not so much in building a boat.  I realized early that a sixteenth here and a sixteenth there soon adds up to errors in real inches.  The tolerances are small because it all has to fit together and somehow like voodoo, keep water out.  My usual tolerances are not good enough because, it turns out, that recent science has shown that water molecules are smaller than an eighth inch.

The angles of the end cuts were not specified in the plans.  In fact, I had to resurrect my long dormant high school geometry knowledge in order to calculate the angles.  Working with the plans a bit, I got the length and the height of the triangle that would be the end of the boat.

Out comes the trigonometry reference.  Looking at it and with some research on the interwebs, I realized there was a magic word I remember being thrown about in high school trig that I never did decipher: SOHCAHTOA.  This time around it made sense.  Of course!  Sine, cosine, and tangent.  Opposite, adjacent, and hypotenuse. So I had the opposite and adjacent sides (TOA!), and so used tangent to calculate the angle.  Fucking magic!

The angle was so frustratingly close to 45 degrees that it made everything just a little bit more complicated.  43.5 degrees.  Looking at a particular angle drawn on a board, it wasnt easy to visualize whether the angle (or its complement) were correct for that cut.  Yet, the 3 degrees difference between the two was maddeningly significant.

In fact, after all that work, while I managed to cut the long lateral pieces at the right angle (43.5 degrees, FYI), I managed to cut every end piece with the wrong angle (it should have been the complement at 46.5 degrees).

As I predicted, this tiny 3 degree error would make our lives slightly crazy as every stringer came together with a frustrating little gap or overhang at the ends.  Grrr.

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