Woah! Sorry for the lag in posts here. I've just completed a move to CT and my time has been a bit stretched thin. Oh yeah, and there was that whole Holiday Thing that you may have noticed. But enough excuses, much water has passed under the transom so let's get to it!
I'll start with the bad news. Due to the poor economy, the foundry has less work than usual to do. That means that when I called them up 10 days after we'd delivered the ballast plug to them, they'd already poured her! Aargh! We didn't expect that to happen for weeks, and we really wanted to get some video of the process for the blog. My apologies. As a meager substitute, here's a video of the students at IYRS pouring lead into their Beetle cat centerboards during the 2007 school year.
On a more happy note, there are photos of the sheer clamp! Woo hoo! In case you don't know, the sheer clamp is a rather thick, stiff length of wood that goes just below the sheer, down the entire length of the boat. This timber helps to stiffen the boat, it provides a solid fastening foundation for the deck beams, and it ties the deck to the hull. The sheer clamp is often a straight-grained wood such as sitka spruce, and it's absolutely knot-free. Wood gets its strength from the continuity of grain; knots interrupt that continuity, and thus weaken it. Our sheer clamp is sitka spruce, a wood renowned for its strength and straight grain. Masts are often made of this wood. We scarfed 2 long boards together to get the 40+ foot length that we needed for Cherokee. Here they are at the aft end. The sheers are marked with the red arrows, by the way.
Here they are going forward.
But, wait, what was that green arrow at the aft end? Now THAT was an interesting bit of fitting. Let's look at that again.
As the sheer clamps come to the aft end, they need to mate just right with the curved transom frame. This is a tricky fit, for the clamps also have to fit snugly up against the hull frames at the same time. The process is to adjust the fit at the transom frame a little bit, which allows the clamp to move outboard and close in on the hull frames, and gradually sneak up on it. If you take too much off at the transom end, the clamp will move nicely up against the hull frames, but then be loose at the transom.
For a while we were trying to notch the ends of the clamp to go over the transom frame. You can see how the oak frame is coming up into the clamp (the straight-grained piece going left to right) here:
This was how it was done in Jill, but it soon became clear that the shape of Cherokee's transom was different enough from Jill's to make that type of fit impossible. You can see how much wood was being taken away to fit the clamp to the transom frame...
There was hardly anything left to extend past the frame. So we just had the clamps end at the transom frame.
We also fit a small backing block in between the clamp and the planking just forward of the transom frame.
This helps to support the sheer clamp. Once more, though, a tricky 3D fit as the hull and clamp are both curving and tapering back there. And, nope, that last photo does not show the final fit. It was much nicer than that!
Meanwhile, Abe has been painting all the caulking with white primer above the water line, and Detco 2-part primer below the waterline.
Once that was done, it was time to putty all the seams. We're using different putties above and below the waterline.
The white stuff is relatively easy to apply, and it cleans up well with mineral spirits.
Below the waterline is another story. We used Detco 2-part seam compound, one of the smelliest, most effective products out there. It sticks to everything, has no solvent for clean up that I'm aware of, and it needs to be warm to cure.
It hasn't been warm.
So, we spent a few hours applying this stuff, and then tented the boat to trap the heat from a couple of oil radiators (read: safe) to keep it all warm overnight.
It worked quite well, and the boat is now officially caulked and puttied. That's no small milestone.
Joel has been laying in the supports for the cockpit sole, and those are coming along nicely.
We're also painting the inside of the boat below the waterline to help preserve things. This is a step that probably wasn't done on the original, but we think the added protection is worth the effort. The interior will be finished with Outdoor Oil above the waterline.
With the sheer clamp installed, we began working on getting the top edge of the sheer plank ready for the deck beams. We use a camber mold to show us how the deck camber will meet the top of sheer planks. In case you don't know, the camber is the curve of the deck as it slopes down from the center of the boat to the sides. In this photo, you can see the camber mold (red arrow) lying across 2 cross spalls.
The camber mold is the exact shape of the deck camber.
First, we cut all the frame ends flush with the sheer plank so that they don't get in our way. A thin saw like a Japanese saw or a Fein tool work beautifully for taking off the oftentimes thin bits of frame end.
We then put our camber mold across the boat and on top of the sheer planks. Here you can see that the edge of the plank doesn't exactly fit the angle of the mold (red arrow):
We want the board that will come out from the decking to the top of the sheer plank to sit exactly flat on the sheer plank. So, a little planing out the outboard edge of the plank, and all is well.
Now we're ready for the deck beams. Abe has been working on getting the beams shaped and ready for fitting.
And finally, they can be installed. You can see the difference between the 3 deck beams and the 2 cross spalls in this photo.
The cross spalls have no camber, while the deck beams describe the shape of the deck.
That's it for now!