Coronet1885

America's Most Historic Yacht

Progress through March 2010

Posted By on August 9, 2010

Working with large timber projects presents some tricky problems that you don’t really run into when working on small boats.  One of these involves drilling holes.  How exactly DO you drill a hole through 24” of oak, and come out exactly where you want to on the other side?  If your angle is off even the slightest amount, you can end up with your exit hole coming out pretty far away from where you want it to.

One set of holes that have to be right are the holes that go down the center of the keel.  These are used to fasten the scarf joints together, to fasten the floors to the keel, and to fasten the ballast to the keel.  Getting these holes right is particularly important because the keel has all kinds of other fasteners coming into it, and you want to give those other fasteners as much room as possible.  Also, if you know exactly where your through-fasteners are, you can make sure to avoid them when drilling other holes for screws and bolts.

SO, Leo has been working on this problem.

He decided to build a jig that holds the drill exactly perpendicular to the keel.  This jig has a series of hole that guide a very long drill bit down into the center of the keel.    The open end on the left slides over the keel, and the whole thing is clamped in place.

Here, you can see the starting holes he’s made on a test piece.

You can see that they line up very well.  He’s using a particular type of drill called a barefoot auger.

This drill doesn’t have a little screw point on it like you find in a typical auger bit.

Sometimes bits will wander as they go through wood.  They can follow checks or grain patterns or just a soft section of wood and can exit the wood in an almost random manner.  There is some debate over whether or not a barefoot auger goes through long runs of wood with less tendency to wander, some people swear by them, others at them.  Leo started with one.

Remember how those entry holes started off right in the middle of a straight line?  Here’s how they came out.

Pretty close, but they wandered a bit up and down from the reference line.    He kept fine tuning it until he could dial it in pretty much every time.

Here’s an interesting aside, by the way.  Coronet had a lot of iron fastenings in her, and over the years, some of them simply dissolved in the salt water environment.  However, dissolved does not necessarily mean “gone.”  In some cases, it means, “moved.”   For instance, when the planking was removed from the stem, there were these odd deposits in the spaces between the keel and deadwood.

You can pull them out and handle them.

I’ve seen the same thing down in mine shafts.  This is iron oxide, redeposited.  It’s layered, like filo dough made from rust.  It crumbles easily in your hand.  This little cookie used to be a whole lot of nails.

But, back to the boat.

A lot of planking has been removed recently, and the stem is gone as well.

There’s been a lot of time spent on stock prep.  These oak slabs will most likely be made into futtocks (parts of a frame) and deck beams.

Upstairs, Eric has been working on the rudder post.

Here’s the original part.  The rudder post is the vertical part with the metal straps on it here:

You’re looking at the aft end of the boat.  The rudder attaches to those metal straps.

The new rudder post, like the old one, uses mortise and tenon joinery to lock it into the aft end of the keel.

That’s the keel on the right, and the rudder post on the left.  You can see the mortise holes in the keel that the tenons on the post will slide into.

The guys have been getting some practice in making rolling bevels using the ship’s saw.  Here’s one test piece that they were fooling around with.

Of course, when they fool around, they may be using a 400 lb chunk of wood…

More coming soon!


Comments

2 Responses to “Progress through March 2010”

  1. I am an old machinist and have done some very large machine work. I find it absolutely fascinating that ship builders like you fellows can do the precision work that you do on such a large scale. We machinists have machinery with thousandths of an inch graduated on the dials which tend to make working close to a great deal mathematics. Your work like my wifes who is a boat canvas worker seems bordering on witchcraft. I find it absolutely amazing that you can fit such big timbers together with the kind of precision needed to build such a fine boat. I have built some small sailboats in the 20 and 30ft range and have longed for the precision machinery of the machine shop to get the joinery work accomplished. You fellows have my absolute admiration. Doug

  2. admin says:

    Hi Douglas,
    Like your work, our work is very mathematical as well. However, we get to deal with wood movement that sometimes is amazing to behold. Add water, even in the form of humidity, and some of these planks expand like a sponge (an apt analogy, since the cell structure is similar). You guys get it too, just on a much smaller scale.

    And anyway, we prefer to call it sorcery. Witchcraft is SO 1700’s.

    Regards,
    Tom

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