What a sport! Almost there...
Ok, ok, that's the wooden plug for the ballast, on the way to the foundry in Providence. And, yes, it's still heavy as heck, so he gets points for holding that baby up.
And there it goes...
Back to serious work, Robin has been working diligently on the sheer clamps.
The sheer clamps are long pieces of very straight grained fir that will run just below the sheer of the boat from front to back. The deck beams are fastened to them, and they are bolted to every frame. In a word, they strengthen the structure of the boat tremendously,
The boat is getting closer to being able to hold its shape without any help from outside forces. The ribbands and molds provided the initial hull shape, but the frames and planking have now taken over that duty. We've added in cross spalls that span the sheer from side to side to keep the top of the boat from flopping outwards and losing shape before removing the molds. Robin has now removed the last ribband from along the top of sheer.
This ribband gave us a place to attach the top of the frames as well as stiffened the sheer of the boat. With it gone, we can now cut the excess frame length from above the sheer.
This allows us to bevel the top of the sheer plank and the frames just a little bit so that the curved deck will come down and sit exactly flush when it's installed. It does give the boat a slightly bare look, almost like a canoe. Right now the cross spalls and the bracing that you see here are the primary things holding the shape of the sheer of the boat. We'll only remove them after we've got the sheer clamp and deck beams in place.
The next thing up is the mast step.
This was cut out a while ago, but now it's time to fit it to the boat. The mast step sits on top of the floors, and provides a solid landing for the mast. When they talk about "stepping the mast" they mean fitting the bottom of the mast into the mast step. The mast step is a very beefy structure, and it has to be. It's made of thick oak and is designed to take the forces transmitted down from the mast and spread them out over a wide area of the boat.
The forces coming down through the mast are really quite substantial. First of all, you've got the weight of the mast, boom, and sails, all coming straight down and concentrated at the bottom of the mast. If you took a gallon of milk and balanced it on your leg it wouldn't hurt, but if you took that same gallon, set it on a wooden dowel, and That on you leg... ouch. And with a mast, these forces are multiplied by the fact that you've got rigging pulling down on the mast as well. All these downward forces are transmitted right onto the mast step. Oh, and that's not all. You've also got all the forces acting on the sail that come down to the step as well. If you didn't have something like the mast step to spread out all this energy, the boat would fold up and snap at the point where the mast met the keel.
This is why we don't make the mast step out of light weight wood. Balsa, for instance, is right out.
Later on, we'll have photos of some of the other ways we'll be dealing with these forces that are transmitted along the mast. As a teaser, I'll just say that they involve metal.
That light piece of wood that you see on top of the mast step is a wedge that is exactly the same angle as the mast rake (the degree that the mast is set off of vertical). Since the mast step meets the mast at exactly a 90 degree angle , we need to install the step so that its top surface is exactly perpendicular to the mast rake. This wedge sits on top of the mast step in the opposite direction of the rake of the mast, so when the step is at exactly the right angle, the wedge is perfectly level (i.e., no rake).
Here we've got the mast step held in position so that it's exactly at the right angle. Now we have to fit it to the floors so that it stays at this angle when it's installed. We do this by notching the step to fit on top of the floors at just this angle. We use a compass to mark this.
This gives us a way to accurately measure how much we need to notch the step at each floor.
Now when we install the mast step, it will sit solidly on the floors at just the right angle. We next drill for the drifts that will attach the step to the floors. When we marked the step for the frame notches, we also marked the angle of the floors beneath the step.
We use a ruler clamped to the step at exactly that angle as a guide for our drill when making the holes for the drifts.
And here's a handy trick:
If you need to drill a long hole like this accurately, you can use the line of light that reflects along the side of the drill bit as a straight line to align with your guide.
Even when the drill is spinning (actually, Especially when the drill is spinning), you'll be able to see that light line as a straight line right next to your guide. This allows you to drill an angled hole with a high degree of accuracy... at least in the side-to-side axis. You'll need someone else watching to keep you lined up in the front-to-back axis.
That's the report for now, sheer clamps are coming!