A Shipwright in Training

Ah, working with wood.  It’s been over a month since I’ve actually needed to hold a plane and use it with any degree of skill.  I volunteered to make one of the garboards for the six meter so I could get back into the swing of things last week.

It was weird.  I felt like taking a nap.

Creating the spiling for the plank was easy… simple, accurate, repetitive work.  But when I got the spiling down onto an actual board suddenly it all came home how many little things I needed to take into account.  The garboard is very long.  Do I do it in 2 parts joined by a butt block or make one long plank by scarfing two planks together?  Make sure I remember to add bevel wood… oh, wait, the rabbet bevel is actually smaller than 90 degrees… subtract bevel wood from the outside face of the plank.  Does the fact that the plank gets hollowed on the outer face have any effect on the way the plank should be oriented (sapwood side in or out?… it will naturally cup up towards the sapwood)?  Since the plank is backed out on the outer face at the aft end and on the inner face at the forward end, the thickness reference marks on the edge of the plank have to be battened out rather than simply scribed.  And then there’s the matter of adding in the rabbet to the plank.  To top it all off, we’re using good wood here, sapele (a close match to mahogany) and it isn’t cheap.  So another level of complexity is working out the best use of the materials we’ve got on hand.

The mantra for all woodwork is the same mantra that I think makes life manageable:  Slow down, take it one thing at a time.  I know, you have to plan for all these things.  However, if you do your layout just thinking of one step at a time and draw each layer, the ways that they interact and the order in which to do each one will become obvious. 

So,

• despile the pattern onto the board.
• Mark where the butt joint will be after looking at the boat (you want to be at least 3 bays and 3 planks away from any other butt joint).  Yep, decided on a butt joint instead of a scarf.  The scarf would have made for a very long, very unwieldy 22′ long plank.  Fitting it would have been a bear.
• Lay out the usual frame locations
• Lay out the rabbet (I’ll get to that)
• You can’t lay out the thickness reference lines until the plank is cut out and planed to the pattern lines
• Make your backing out templates
• Take the bevels and make up a bevel board for your bevel wood subtractions

That’s it to start.  Here we go.  Spiling batten laid out on the sapele.

The plank is in 2 sections, a 6′ and 16′ section.  The 6′ section is in the forward end of the boat.  The 16′ section looks pretty dang long.

And you can barely see that it overhangs this board by about 4′. 

I started by cutting out both the forward and aft plank sections, leaving a little extra length for fine tuning the butt joint later.  I decided to start working on the shorter plank since I figured that if I bollix it up, there’s less wood wasted. 

Even though it’s a short board, there’s almost 3/8″ backing out to do. 

This makes for a lot of shavings.

Sapele is kiln dried, and it works far easier than I’d been told.  Everyone said that it would get a fuzzy texture from the planer, but it machined and planed quite smooth as long as I paid attention to the grain direction. 

My favorite tools for backing out were these 2 planes.  The smaller radius plane did a good job of hogging lots of wood out of the middle, and the shallower backing out plane cleaned up and smoothed the grooves left by the first plane. 

As I said before, the hollow changes along the length of the plank.  That means that there is a small flat spot in the area where the hollow shifts to a bulge on the face of the plank.  A little tricky getting that transition nice and smooth. 

Everything goes better when you lay out all your lines.  It gives you time to think about how you’ll each step, and makes it easier to construct the plank in your head first.

In this case, after laying out the rabbet, Warren and I decided to radius the corner of the rabbet to reduce the tendency of the first broad to split in the forward end.

What the hell is he talking about?? 

I promise, I’ll try to make this rabbet stuff a little more obvious as time goes on. 

The top 1 1/16″ of the plank is rabbeted down to the level of the inner planking (also called the liner).  The first broad sits on top of the liner, and laps over the garboard at the rabbet. 

Here’s the rabbet after being roughed out with a router.

I like this router, it’s a laminate trimmer with an offset base.  This allows you to support the weight of the router on solid wood as you cut out the rabbet. 

I freehanded the cut, giving the rabbet lines a wide berth just in case of a slip up.  Routers make big mistakes in an instant if you’re not careful.

Then, on to hand tools to finish up.  The Veritas rabbet plane on the left does a nice job of making the vertical face of the rabbet.  The LN #140 makes a nice wide cut.  It’s a rabbeting plane as well, and has a skewed blade which helps slice the fibers where you run into little grain reversals. 

Getting close to my line.

One thing to pay attention to is the slope of the rabbet.  If this were a flat board, the rabbet should just be level with the surface of the board.  But this plank’s face rolls along its length.  It starts by curving up where the outer face is hollowed out.

I need to make the base of the rabbet mirror the curve of the plank face beneath it.  It’s easy to see how to do this at the end where there’s a cross section of the plank, but you can’t see the curve changing anywhere else without cutting the plank and getting another cross section.  One way to deal with this is by using calipers.

Here I’m measuring the rabbet to plank face thickness.  The caliper holds this measurement.  Then I pull the caliper out towards the edge of the rabbet.

See the gap?  Now I know that the rabbet thicker near the middle than at the edge.  If the rabbet mirrors the opposite face of the plank the thickness will be consistent.  So, I plane down the inner edge of the rabbet until the 2 faces are parallel. 

While you’re doing all this planing, don’t forget to clear your plane. 

You can get so carried away by what you’re doing that the chips will compress as tight as book pages in there.  I had to pry them out with a screwdriver. 

So, plane along, check your work, and after a while you get a nice rabbet.

In fact, at the forward end of the plank, the whole plank is rabbeted down to liner thickness.  The first broad will notch around that curved tall part there and rest on top of the rabbeted part of the garboard.  When the boat is done, that raised area will be all you’ll see of the garboard from the outside, and an amateur (like me) will think that they’re looking at the end of the plank.  Au contraire!  As you can see, the garboard extends a good ways beyond what you’ll be able to see on the finished boat. 

It’s handy to leave notes for the person who comes along after you making the first broad.  In this case, they’ll know that the rounded edge here is a 1/2″ radius.  They’ll be able to used a 1/2″ drill to make that curve exactly right.

After the rabbet is done, just add the caulking bevel to the lower edge of the plank

and you’re done.  Tiny bevel eh?  Only 3/32″ off the face, extending down about 2/3 the thickness of the plank.

I made some clamps to hold the plank in place as I was fitting it to the boat.

The clamps have a little base that I screwed through the liner into a frame.  I’ll fill these holes when I’m done.  The clamps also are grooved to allow them to spring a little bit, like featherboards (for you woodworkers out there). 

Perhaps I can do a little explaining about what you’re looking at here.  The liner was patched after someone put their foot through it.  It’s only 1/4″ thick cedar… pretty delicate stuff.  So, don’t be confused by the different colors and the sloping shape.  It’s just a repair.

You can see that the liner sits below the level of the planks above it.  That’s because this is a double planked boat.  Cedar liner on the inside, mahogany planking on the outside.  The garboard is a special plank because it’s as thick as  both the inner and outer planking combined.  There is no liner underneath the garboard.  The garboard butts up to the liner on it’s top edge and sits in the keel rabbet on its lower edge. 

The rabbeted edge is as thick as the cedar liner.  What I’m doing here is fitting the garboard so that it snugs right into the keel rabbet and tight against the cedar liner.  When this plank is hung, there is a space left for the next plank above it, the first broad, to be installed over the garboard rabbet and the cedar liner.  The first broad is about half as thick as the garboard, just like all the other outer mahogany planks.

A picture’s worth a thousand words?  Hmmm.  Explaining a picture takes at least 200. 

So, that’s been the last few days.  Tomorrow I’ll steam this puppy into place and begin working on the aft section of the garboard.  There’s gonna be a big pile of shavings…

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This entry was posted on Thursday, February 7th, 2008 at 9:40 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.