Spent my post-Hurricane Sandy morning checking with the neighbors, the police department and the fire department . . . nobody within walking distance seemed to need my help, although the neighborhood is a mess, driving is dangerous, and there is no electricity. By the afternoon, I had time to work on the Mayfly . . . with no lights or power. The lines for various components needed to be set on plywood though, and that does not require power.
The nails are set and a flexible wooden batten is laid along the sheer of what will be one of the boat’s sides.
Per Michalak’s book, I set lines along the short axes of two 1/4-inch sheets at 2-foot intervals, then defined the intersecting edges of the piece of the boat at these intervals. Think of it as a 16-foot long X-Y Graph. At each intersection, I drove a 6d finish nail, then laid a wooden batted along the nails to trace the edges of each of the hull’s side panels. Seems simple enough, but the small hand-lettered dimensions on the book’s drawings (I didn’t spring for full-size plans) made for delays due to pensive review. In addition, a point on each sheer, six feet back from the bow, seemed unfair – perhaps off by a 1/2- inch. I drew everything else and latter jumped on the Michalak boat-building forum to see if there were errata in the measurements. Someone later volunteered that they ran into the same problem and just drew a fair curve, which is what I’ll do next session.
Today’s progress involved only a lumber purchase.
I’d been contemplating which grade of plywood to use. Michalak’s book says luan or BCX is acceptable, ACX is his preference. I had been thinking of using marine for longevity, and eventually found it locally at an honest-to-goodness old-fashioned lumber yard. There was little besides luan and BCX at Lowes and Home Depot.
At the lumberyard, quarter-inch marine was $47/sheet vs. $25.25 for ACX. But the marine sure did look better, no voids and two A-finished sides. In the end, though, I chose ACX and bought three 1/4-inch sheets. These will be used for the hull’s sides and decks. I’ll buy the two 1/2″ sheets when the bottom goes on the boat.
“So what’s with the acronyms?” – Glad you asked. Plywood comes in various grades and is manufactured using different wood species and glues according to purpose. Each side of the sheet is assigned a grade of A, B, C, or D, where A is near perfect and D is, well, not pretty. Exterior grades also get an “X”. The ACX I bought is Douglas Fir, which is higher quality than pine. The C faces have holes from knots. These will require filling and fairing when the hull is built. Plywood grading is further explained here. And here.
There it is . . . everything you always wanted to know about the fascinating world of plywood, but were afraid to ask. 🙂
Otherwise, no work on the boat today. I had other commitments and Tropical Storm (?) Sandy is heading our way tomorrow. ‘Nuf said.
Tonight, I ripped the lumber for the yard and boom. These will hold the top and bottom of the sail to the mast. Each will be formed by laminating (glueing) two 3/4″ x 1-1/2″ pieces together. Since these will each be 11 feet long, I ripped the required pieces from two 1 x 4 x 12’s using a table saw. This one is on loan (Thanks, Fred H!) – my saw would do it, but this heavy duty model is better for the task.
Horizontal and vertical featherboards. I built these 20 years ago. They are huge. What was I thinking? But they do work great . . .
The four sticks at right will form the yard and boom. The leftovers at left are thin and flexible, and will be perfect battens for drawing the long curved lines required to cut the 16-foot sides of the boat from plywood.
The problem with these rips (cutting a board with the grain along its length) is that the length of the board makes accurate alignment difficult. To best position the board, I clamped featherboards to the table saw to force the wood laterally into the saw’s fence and downward onto the table surface. The finger-like projections are set on an angle that allows the piece to move forward into the blade, but limit backward motion. They work well – here’s a video description of a set-up the differs slightly from the photos above –
My 12- year old daughter helped me to draw up this frame, then cut and assemble the lumber. This one will go 2 feet back from the bow of the boat, and will also be removed when the hull is assembled.
Temp Frame 2
My daughter was a pleasure to work with and her help was most appreciated. While we worked, she corrected her Dad’s faulty measurements. She also gained experience using the portable electric drill and jig saw.
My youngest holding Temporary Frame 8.
There is something about cutting the 1st piece of wood the commits you to the build process . . .
Cleaned out the garage the weekend . . . this bay will be the boat shop for the next few months.
The shop is about 8′ x 15.5′ . . . it’s gonna be tight, but the 17-ft kayak up on the wall was built in the same space.
Tonite, I ran to Home Depot and bought a few 1 x 4’s, then assembled one of the two temporary frames using No. 8 screws.
The finished temporary frame for Position 8. This frame is 4′ wide and will hold the two sides and the the bottom in place at the boat’s widest point. It shows the cross-section of the cockpit where the sailors will sit. This frame will be removed when the hull is assembled.
A small effort, but its the 1st accomplishment.