A Shipwright in Training

Of course the whole reason for taking all these lines and making all these full size drawings is to eventually arrive at a boat.  But, we’ve been working so hard at getting everything fair and just right that the actual transition from lofting to boat parts gives us a little sense of the willies.  Now it’s time to step up and show what you’ve got.  Remember how to use your spokeshave?  Remember how to cut a tight line on the bandsaw?Â

Not a bad time to procrastinate by sharpening your tools.

So, how exactly does one move from flat drawing on the floor to a boat part that you can juggle and whap somebody with? 

Here’s one way, but it’s not the only way.  No fundamentalist boat builders here.

We start by making a pattern.  To do that, we need a way to transfer the lines from the lofting to pattern stock.  Nails work really well.

Here, we’re patterning out the apron.  The apron is just behind the stem, and it serves as a surface to fasten the planks onto when they come up to the stem.  What we’ve done is taken nails that have a wide, sharp-edged head, and hammered them into the lofting sideways along the lines we want to transfer.  Now the sharp edge of the head is sticking out exactly along the line below it.  You can see we’ve  driven in nails along 3 lines running vertically.  The leftmost line is the aft face of the apron.  Just forward of that is the bearding line.  The Bearding Line defines where the planks will first touch the apron as they curve inwards towards the stem.  The rightmost line is the forward face of the apron (and incidentally is also the apex, or middle, line of the rabbet.  Recall that the planks come into and attach to the stem in a groove called the rabbet.  The aft edge of this groove is the bearding line, the place where the inside corner of the corner hits the rabbet is the apex line, and the forward edge of the rabbet is called the rabbet line).  The 3 nails in a row angling down define the lower edge of the apron. 

So, now we take a chunk of thin plywood and put it on top of all these sharp edges, and give it a good press.

And voila!  We have the pattern marked into the plywood.  Now we take a batten and fair all these little grooves into a nice line,

and there you have it.

The shape of the apron is now transferred to the pattern stock.  Cut it out, shape it carefully so that it fits onto the lofting exactly, and you’ve got yourself a pattern.  After that, it’s a simple thing to trace that pattern to a chunk of wood that you like, and make your part.

Here’s the apron cut out (the pattern is in the sunlight behind it), and 2 other patterns have been cut out and fit on top of the lofting (the stem and forefoot). 

There’s a forefoot

And here’s all 3 parts cut out and fit together.

Things happen when you move to 3D.  For one thing, this is where it really matters if your parts fit the lofting exactly.  You also have to get the faying (surfaces that butt up against each other) surfaces to fit exactly right.  Sure, we’ll put red oxide paint and bedding compound on these surfaces before we attach them, but you really want those joints to be perfect.  So, there’s a lot of fussing and fitting to get everything perfect.  The real real kicker is when you get everything just so and the parts somehow don’t‘ fit like they should.  In this case, the forefoot - stem joint was the tiniest bit out.  Turns out that the forefoot had begun to twist just slightly along its length.  Luckily, the twist was small enough for us to straighten it out with hand pressure.  That means that later when we attach the backbone to the strongback we’ll be able to pull it all into shape exactly. 

So, no problem.

But, still, the oak we’re working with here is dead green (like, wet-to-the-touch-inside green) and we want this stuff to move as little as possible when we’re building the boat.  The solution (one of many) is to shellac every part as soon as we’re done with shaping it.  This equalizes the moisture loss across the part and reduces the chance we’ll have parts blow up on us.

This year we got a lot of nice crooks to pull these curvy parts from.  For instance, the forefoot you see above came from a crook. 

Here’s a crook that the Bulldog team will use for their stem:

You can see how the tree has grown in pretty much the shape of the stem already.

This makes for a very strong part.  Unfortunately, when they cut this out of the tree they found a bark inclusion on the other side.

This is where the tree essentially folded over on itself, trapped some bark, and kept growing.  Luckily, when they placed the stem pattern on this piece, they were able to work around the inclusion. 

We finished patterning and cutting out the transom as well.

The transom is made up of 2 boards, glued edge to edge.  There’s 2 drifts (bronze rods) that span the joint to strengthen it.  You can see a bung that covers up the hole drilled for the drift.

And of course, we shellac everything as soon as we work it to minimize warping, splitting, etc.

Meanwhile, project #2 has come into the shop. 

This is Madcap, a six meter racing boat designed by Fredrick Hoyt and built in the famous Nevins boat yard back in 1924.  She’s in phenomenal shape, and the work we’ll be doing on her is much more like the kind of restoration job one might expect to get in a regular boat shop.

We’ll be refastening her hull (taking out all the old screws and replacing them with new screws), replacing the garboards and first broads (lowest and 2nd lowest planks), and returning her deck layout to the original configuration. 

The way she’s laid out now is with one cockpit and a small deck house.  This makes it into a nice day sailer, but it’s not how she was originally laid out.  When she was built, there were 2 cockpits, one for the boat steerer and one slightly forward for the grinders.  The tiller was also below the deck level.  The 2 cockpits allowed there to be more decking crossing the boat in the middle, and those additional deck beams strengthened the hull.  There was no cabin top.  The idea was to have as few things up on deck creating wind drag as possible.  The owners want her to be a full-on racer like she was originally, so we’re rebuilding the deck with 2 cockpits. 

The reason that this boat is in such pronominal shape is that every year the owners would coat the insides with pentachlorophenol, an extremely effective and toxic preservative.  We’ve got to figure out how to encapsulate this stuff inside the wood so that it doesn’t get out.  We’ll probably seal it in with a couple of coats of shellac after we find out how to clear it off the surface wood. 

Since I’m the old guy in the team, it’s assumed that I have the weakest immune system.  When I start to get woozy and vomiting blood that’s the sign for everyone else to take a break and get out of the boat for some fresh air.  It’s an important job, and I feel proud to have something vital to contribute to the team.

We went back to Mystic Seaport as a class this Friday and got to cruise around the warehouse boat collection again.  With over 400 boats there, we could take a week and not get bored.

A  tiny sampling:

The transom of a rowing boat.  Yes, that’s a tape measure on the top.  This thing is about  16″ wide at the sheer.

A beautifully crafted seat.

And a molded veneer kayak by the Danish builders Sorensen and Kobburup.  This is the front edge of the cockpit coaming.

Damn that’s just sexy.

In the meantime, it’s been foggy and beautiful around here and I’ve been trying to get outside as much as possible.

These were taken at Napatree point, near Stonington CT.

The water’s warm, so people are still swimming. 

New England rocks.

This entry was posted on Sunday, October 7th, 2007 at 1:13 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.