Skat Hardware: Blocks
by Tidmarsh Major

Though I haven't made a whole lot of visible progress on the hull lately, I've been working on hardware in preparation for rigging once I have the hull finished. First off, I've made a number of blocks in anticipation of all the lines necessary for a gaff rig. I used drawings in Edson I. Schock's How to Build Small Boats, which contains plans for a catboat that Jim Michalak used as a model when designing Skat.

(click image to enlarge)

My first dilemma was determining what thickness of brass to use for the body. The instructions called for "sign brass" but didn't specify what that meant. After a discussion on the Wooden Boat forum, I decided to use .064 brass.

I'm fortunate enough to know someone who teaches machine tool technology at a local community college, and he used a CNC router to cut the bodies from my 12" x 12" sheet of brass. He then bent them and drilled the holes for the pins.

For sheaves, I bought a sheet of 1/2" UV-resistant VHMW polyethylene. I used a 1 3/4" hole saw to cut sheaves approximately 1 1/2" in diameter. I then chucked them into a drill press and used a small half-round Microplane rasp to cut grooves into them.

(click images above to enlarge)

Next, I enlarged the holes to 5/16" and pressed in oil-impregnated bronze bushings to fit a 1/4" shaft. Although to polyethylene would have turned easily on a shaft by itself, I decided to go with the extra durability of a self-lubricating bronze bushing for this high-wear area.

Now came time to assemble the blocks. Rather than turning pins as shown in the drawings and peening the ends, I used partially threaded cap screws to allow for easier dissassembly and repair.

After assembly, I cut off the excess threads extending beyond the two jam nuts (leaving one nut screwed onto the bolt while cutting to clean the threads after cutting), and rounded the ends with a file.

Though I was happy with my work, I realized that while these blocks would be fine for the deck or the boom, I didn't really want a pair of them tied to the masthead, swinging around and banging up the finish on my mast. What I needed were a couple of rope-stropped blocks. I searched on the web, and found a few sources, including one article here at Duckworks and one from an old Mother Earth News.

Rather than use exotic woods, I used what I had available: Douglas fir. For each shell, I cut two five-inch long pieces of 1 x 2 . I then clamped them side by side and used a handsaw and a chisel to carve a 2-inch long mortise in the center of each half, 5/16" deep. Thus, when the halves were assembled, I would have a mortised hole 2" long and 5/8" wide to fit the 1 1/2" diameter by 1/2" thickness sheaves that I had previously turned. I then glued and clamped clamped the two halves together using Titebond II exterior wood glue. When the glue had dried, I then drilled holes through the shells, 7/8" from the bottom of the sheave mortise. The offset sheave leaves room for a 3/8" line through the top of the shell.

I used a jig saw to round the ends of the blocks. I had originally planned for a 2-inch mortise with 1 1/2" inches glued area at the top and bottom, but the blocks looked too long. I trimmed them down to a glued area of a 3/4" radius at each end, for a total length of 3 1/2" rather than 5", which looked better to my eye. I then used a Microplane rasp to cut a groove around the shell for the rope grommet and cut pieces of brass rod to fit the shells. I test assembled with some 3/8" nylon line I've been practicing my splices on, as I haven't ordered any polyester line yet.

I'm now giving the shells a few coats of spar urethane before final assembly. These wooden blocks weren't hard to make, and I find shaping wood much more enjoyable than metalwork. If I had it to do over, I'd probably make rope-stropped blocks for all my rigging and skip the brass work. In particular, if I didn't have access to a CNC router, I wouldn't make brass blocks. For fun, I cut one brass shell freehand with a jigsaw from the scraps left from the CNC router. Although it is functional, it isn't anywhere near the level of finish achieved in the machine shop. (See if you can spot the odd one out in the picture of finished brass blocks.) I think my hand-carved wooden blocks are far better looking than my hand-cut metal ones. As always, though, your mileage may vary.

Tidmarsh Major
Tuscaloosa, Alabama