New Bottom Planks

It’s not time to install them yet–that won’t come until after the inner layer of 1/8″ marine plywood is already fitted and installed.  But we need to bend the outer planks to the shape of the hull while we can still get to the frames to use them to clamp the planks to.  So now’s the time.  Boatbuilding, as with many other endeavors, is often not done in a straight line.  You do things when you can, when you have the extra help, when you need to.

The first step is to sort through the milled lumber and pick the nicest grain for parts that will show.  We allocated the pretty stuff to topsides planks, transom planks and ceiling.  That leaves the not-so-pretty stuff for the bottom, which will be covered with paint.

We’ll start with the garboard (that’s the plank that lies next to the keel, and incidentally, where a lot of leaky bottoms start) and work out way up toward the chine.

Having allocated our lumber, the next step is to cut out what I call the “blanks”.  I used the old planks (never throw anything away until the project is finished) as patterns to get the general shape of the new planks and cut them out big on with a jigsaw.

Now that last sentence could be a whole blog topic in itself.  I realize as I write this that there’s a lot of “how-to” that gets skipped over.  How big? Bigger on one edge than another? Is there one brand of jigsaw that’s better than another?  After all, the right tool really does make all the difference.  What about grain orientation?  Is there a problem with avoiding sapwood like when you’re cutting white oak?

I know there’s a lot that I gloss over here.  If you’re interested, you can always comment or ask a question.  I promise to answer.  And I promise to tell you if I don’t know.

Back to the main topic, I cut them out two at a time–one for each side of the boat, tracing around the old plank, leaving it 1/2″ big on the bottom and leaving about 3 to 6 inches on the aft end.  This way, if I make a mistake when fitting (which comes much later), I can slide the plank forward and re-do.

Then I presoak these mahogany planks for at least 24 hours before steaming them.  Mahogany, being less dense than white oak, needs less presoaking time.  I would soak white oak for a week or two before steaming.  Then it’s time to steam it.  In this case, since the planks are 1/2 inch thick, they’ll be steamed for at least 30 minutes.

Finally, pull them out of the steamer and quickly clamp them to the frames of the boat.  I only steam the forward planks.  The aft ones are pretty straight, and won’t be stressed by attaching them to the boat without steaming.  Having the forward ones curved to the shape of the hull greatly eases the task of fitting them, which is a topic for another day.