A Shipwright in Training

Once the boat is flipped, the next batch of things just comes along. It’s almost anticlimactic. But, still, I like having a boat-shaped hull right there in front of us all day.

Painting it is a pain, but I’ll get into that later.

Parts parts parts. While Kev was working on making the mast into a nice, tapered rectangle, I bent and cut out the gaff jaws. These are the things that attach to the end of the gaff (that rod that holds the top edge of our rectangular sail up in the air) and slip around the mast.

And then I milled up sheer clamps for everyone. The sheer clamp is a long rectangle of wood that… wait for it… clamps to your sheer. It helps to stiffen the upper edge of your boat so that it holds it’s homely little catboat shape. Here you go, a pile of sheer clamps!

Ok, it’s just the bundle of wood there on the right with blue tape around it. Not Exciting. But then, hey, boat building isn’t all making stuffed dummies that look like Leprechauns.

That fine thing was made by Toma’s wife, Isabelle, and was in the parade. All I can say is… wow.

Ok, on to the How To portion of today’s blog. How to make a square thing round, like, say, a mast. The mast starts out as a long square thing. You taper the ends, but still keep it square in cross section. The trick is to go from that shape to a smooth, round pole that has the same taper.

Here’s the spoiler: you plane it to have 8 sides, then 16, then 32, and before you know it, you’re round.

So, how do you plane it to get those nice equal 8 sides, and then those nice equal 16 sides? That’s the trick alright. Let’s walk through it.

First, you mark out cross sections along the length of your mast. Your final product will be round, so start with a circle that’s centered exactly on the face of the mast.

You make these regularly along the length, and particularly at places where the mast tapers.

Next, draw 2 lines tangent to the sides of the circle and perpendicular to the sides of the mast.

Here’s the first one. Do another one on the right side of the circle, and what you’ve got is a picture of your square mast with the round mast in the center, just waiting to come out.

Now, there are 2 ways to do the next part, and don’t fret, I’ll show you both of them because they are just So Fascinating To Everyone, I’m sure. I imagine about 3 people in the world are continuing to read this part, the rest are skipping down hoping to find another picture of a drunk mannequin or a boat builder with a plumbers crack.

Get out your compass, and set it to the distance from the exact center of your circle to the corner of the box you just created.

Like so. By the way, if you don’t know why we’re doing all this, remain calm. All will be clear in the fullness of time. Then, using that measurement, put the point of the compass on the corner of the box and mark along the edge of the box.

It’s a bit tricky, because the corner of the box is the edge of your mast and the point of the compass wants to fall off. When you mark the box, you’ll get this little mark on the left vertical edge of the box:

Now, do that for each corner, marking down on the edge of the box.

Exactly. Nice job. Here’s what you’ll get:

Now, pause for just a moment and consider what we’re doing. We’re trying to figure out where we’ll plane this long 4-sided mast to make it into a long 8-sided mast. In order to do that, we need to be figuring out where to plane down to in order to make 8 equal sides. You could just grab your plane and have at it, but I seriously doubt that you’d accurately end up with 8 sides. No, we need our friend Geometry. Those marks we’ve just made define the new edges that will be made when we plane the corners of our box down to make an octagon. Imagine 45 degree lines going up and down to the tops and bottoms of the box from those points. Those lines would chop off the corners of the box so we’d end up with 8 sides.

Don’t believe me? Let’s check with our combination square and at the same time do the 2nd method for finding these points.

Take your combination square, and mark out a 45 degree line tangent to the circle.

Notice how you end up exactly at the point you just made? That verifies that you measured correctly. Imagine if we drew a line along the blade of the combination square there… see how you’d get one of your new 8 sides?

Now, this may make your head hurt, but give it a try. You’re looking at a cross-section of your mast, right? However, it’s turned 90 degrees and plastered on the face of the square mast. If we were to turn it back to it’s proper orientation, we’d have to imagine it rotating 90 degrees back into the mast. Now, if it did that, we would only be able to see the points drawn on the face of the mast that we can currently see. We can’t see the top or bottom faces of the mast (unless we turned it over), so we don’t bother to mark points on those faces in our little geometry exercise here. In fact, we only need to put points on either the right or left side of the circle as will become even more apparent later.

So, now we’ve got the points we need to make an 8 sided mast for this face of the mast only. In other words, we need to do this exact same exercise at roughly this part of the mast for all four faces. We’ll get to that later.

Now, we need to figure out where the edges will be for the 16 sided mast as long as we’ve got these nice flat faces to work with. Everything gets harder to work with when you stop having nice flat surfaces to work on.

You noticed how the 8 sided edges were at a 45 degree angle tangent to the final circular shape of the mast? Since 16 is twice 8, you can imagine that the angle you’ll want to determine the location for those edges will be half 45, or 22 1/2 degrees off of vertical, and tangent to your circle.

But you knew that already, didn’t you? Absolutely. Silly to even mention it out loud.

So set your protractor ruler head to 67 1/2 degrees (90 - 22 1/2), align the blade to be tangent to the circle, and just like with the combination square, make a mark on your box side where the blade intersects.

Do this 4 more times, and you’ll get this:

You now have a cross section of your mast with marks that let you know where you’ll plane down to when you start to round this mast.

Remember I said that you didn’t really need to do this on both sides of the circle? I didn’t lie about that, you don’t. The second set of marks just serve as a check on the accuracy of your first marks. I stopped doing full circles after a time or 2. The more efficient ones look like this:

Ignore the pointy part on the left. That’s just an accuracy check and if you really really want, I’ll explain it. Note, however, the 4 lines that define the corners we’ll be planing to.

Remember how we make a bunch of these little things? To know where to plane to, batten out and connect those little lines all along the length of the mast.

Like this. Remember, you’ve done this for all four sides of your mast. The lines closest to the corners will define the edges of your 8-sided mast. Plane the corners down to them and you’ve got yourself a long octagon!

Set the mast up on a corner using little angled blocks,

and start planing that upper corner flat.

Nice low rider pants there, Kev. Rrrrow.

There’s a lot of wood to remove in this first round of planing and some people use a draw knife or a slick. A draw knife is essentially a big knife with handles on both sides that you use by pulling it towards you through the wood. It lops off huge hunks of wood. A slick is a giant, heavy chisel and it does the same thing.

I like using my scrub plane.

It has a curved blade and it lops off big, thick shavings. It takes the bulk of the corner wood off in no time. By the way, you can see how I’ve planed close to the top line there as we’re approaching 8 sides.

Those are some fat shavings. They’re like home made potatoes chips.

Once you start getting close to your lines, you switch to a longer plane with a flat blade to get a nice smooth surface.

So, how do you get to 16 sides, you ask? The astute reader will pipe up and say, hey, we just planed down a new side to make an 8 sided mast, and there are no marks on there. How will we know where to plane to on those new sides?

Keep in mind that all sides are the same width, right? If you look at the drawing we did earlier, you can see that there are 2 marks closest to the center. Those mark the top and bottom edge of the 16 sided mast, and therefore we know how wide the sides are. So, set your compass to that width, put the point on one of the marks, and swing the compass up onto the new side. That will mark the edge of the 16 sided mast up there! Then just connect your points along the mast like before. How easy is that?

If you’re tired of geometry, you can carve your name in the front of the centerboard trunk.

Dang boat vandals.

I did the drawing on the mast while Kev painted and just about killed his back.

I know what a pain it is to lean over the boat since I did my half yesterday. But Kev was a champ and sanded and put a 2nd coat on the whole boat today.

Beautiful! That’s “Beetle Gray.” Standard on all Beetle Cats.

And if that’s not enough of How Things Get Made, here’s a bonus.

How Hounds Get Made.

First, glue up a bunch of strips of wood angled at 22 1/2 degrees on edge.

Be smart and don’t glue the center segments.

Then, round our the inside of your hound to fit exactly on your mast. This takes piles of time and patience. Finally, using something close to magic, determine the proper angle to cut these rough tubes so that they’ll be the hound of your dreams.

If your hound is made up of more than one segment (almost all of them
are), make sure that the 2 segments go together perfectly and that your
magic angle flows seamlessly from one segment to the other. Then, taper your hound from top to bottom and make it all nice and smooth.

Finally, glue that thing onto the mast using thickened epoxy. Use hose clamps and little clamping pads for even pressure.

Voila! You’ve got yourself some hounds!

Now go home, eat some chips and salsa, write a blog and go to bed!

This entry was posted on Wednesday, March 21st, 2007 at 9:26 pm and is filed under Classes. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.