Feb
13
Written by:
Tom
2/13/2012 9:13 PM
But before we get to those, lets see how the planking is going. The Watch Hill 15 is closing in on their shutter plank.
The final plank on a boat is called the shutter plank. This is because it's shuttered in on both sides by other planks. In fact, when any part has to be made where both ends have to fit just right for it to go in, it's called a "shutter fit." When you look at the aft end of the planking on this boat, you can see that it "runs wild" past the transom. The hood ends at the bow are captured by the stem rabbet, but the aft ends can be left long until they are trimmed to fair into the stem. If the aft ends also fit into a rabbet in the transom, each plank would have a shutter fit.
But only one plank is the shutter plank (a.ka., the whiskey plank, because it's traditional to pour some spirits on the plank before installing it. One of the plank, one for the crew...), and that one is being patterned out here as you can see.
There isn't a name for the next-to-last plank, but here it is being drawn on a cedar board.
And 30 minutes later, it's being shaped.
The lobster yacht's planking is coming along well.
Three strakes up on the port topsides, and another 3 on starboard.
You may also notice that the top section of the female molds have been cut away to allow for the plank installation.
Other parts are coming together for this boat. The bilge stringers have been installed now.
You can see that the stringers are made up of a lamination of 2 boards. This was necessary for the wood to manage the bend and twist required of it in the forward section of the boat.
This student is cutting away a bit of the old planking in order to have better access to the forward end of the stringer. He'll then trim off the end of the stringer to match the length of the port stringer. You can see that three lower strakes of planking have been installed on starboard.
Some of the crew have begun beveling the tops of the sheer strakes.
They place a camber mold (the long plywood pattern with the curve cut in the underside) on the top of the sheer plank and check that the bevel matches the curve of the mold. They then adjust the bevel using hand planes.
When the deck beams are installed, they too will be checked with this mold.
Speaking of deck beams... here they are.
You can also see a stack of the short half-beams just beyond the longer beams.
With the planking completed on the sailing dinghy, the focus has shifted to framing.
This student is riveting the frames to the hull. As she peens the copper shaft of the rivet over the rove, there is another student on the outside of the boat holding a bucking iron (essentially, a heavy hunk of metal with one end that's the size and shape of the copper nail's head). Without the bucking iron, the hammer blows would drive the copper nail through the hull. Instead, with the nail backed up by the iron, the blows mushroom the nail over the rove. This process is called peening.
The gaff jaws for the rig have been shaped and attached.
These are also riveted.
You can see the copper roves just below the peened-over ends of the rivets.
And in Beetle cat land, well, it's more planking!
In some cases, the stock doesn't have enough width or sweep to fit the shape of the plank. In these cases, the stock is cut in half, and then scarfed back together at an angle.
Not only does this allow the student to use her stock more efficiently (since she doesn't have to use an extra wide board and cut away the bulk of it), it also makes for a strong plank as the grain of the angled parts more closely follow the shape of the curved plank than it would if the plank had been cut from a straight, wide board.
Speaking of efficient use of stock, here's a little trick for creating backing out templates for the planks. if you take a small piece of scrap plywood, a little longer than the plank is wide, and hold it up to the curve of your frame where the plank will go,
you can trace the curve of the frame along the center of the scrap. Then, take this scrap to the bandsaw and cut along the line you've drawn.
The cut will create a concave and convex curve.
(note: this student has traced 2 frame patterns on this scrap of wood... even more efficient use of materials!) The convex curve will be used for backing out the inside face of the plank,
and the concave curve will be used to rough shape the outside face. Not a bad use of scrap wood, and you get two uses from a single cut.
Some students have begun cutting their rudders out of marine plywood.
After rough cutting, they're shaped using planes and spokeshaves.
Others have cut out their centerboards, and weighted the lower section with lead.
The lead is melted and poured into an opening in the centerboard. Since the lead shrinks after cooling, the top surface of the plug tends to form a slight concavity. To make this smooth and fair with the rest of the centerboard, the top is floated with epoxy with red fairing filler mixed into it. This can then be sanded flush with the surface of the centerboard. After painting, you won't even see that there's a lead plug embedded in there.
Upstairs, some students have begun gluing up their spars.
The triangular braces are laid out in a dead-straight line, and then screwed to the floor. This provides a straight, solid clamping surface for the two halves of spar as they're glued up.
You may recall the long stitch and glue boat that was being worked on upstairs earlier... The outside of the hull has been fiberglassed now. It's coming along nicely.
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