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The 4th layer of veneer is currently in the works. Hopefully I'll have time tomorrow to sit down and tell you about it.

Cheers.  

Strip Planking

Wow!  It has been a long time since the last post.  Lara and I have been busy moving into our new place and I have been sailing on Saturdays.  I'm going to atempt to get up to date with this post; we'll see how it goes.  The photos will hopefully illustrate some of the processes and terms you may not understand. Terms marked with a * also have definitions at the bottom of the post. As always, if you have questions feel free to leave a comment.

I left off with the stringers, keelson, and sheer clamp in place so now we were ready for the strip planking.  We used 5/8" X 1 1/2" Alaskan Yellow Cedar that came in 16 to 20 foot lengths.  The first task was to scarf up* the material into the 42 foot lengths that we needed (see photos below).  In two days I glued up 130 planks at 50 feet long which was quite the production.  With the scarf jig* (pictured below) the process was not as gruling as it could have been.

The shop's method of planking was much different than what I was familiar with.  For the most part, it seems that builders use bead and cove* material and glue each plank to each other.  In our method the planking was only glued together at the stringers, clamp and keelson; the rest was glued and screwed to the bulkheads with no glue in between the planks. I mention this as an interesting fact because the "bead and cove" method ensures a tight seal between the boards, whereas this method leaves gaps or "seams" that are later filled with glue.

 

50 of 100 glued up planks.

  

This is a scarf joint. 

 

This is a scarf jig.

When the planking was finished, we came back and filled the seams with the thickened epoxy.  This was a huge time saver in both clean up of the dripping goo and and in the amount of time it would have taken to glue each plank to eachother.  We were able to get away with this method because there is a lot of athwartship* strength (bulkheads, lockers, and such) in the design of this boat.  This method would not work on tight scantlings (meaning a boat that is built lightly or with less robust materials) or with a design with few bulkheads.

Once the boat was all shmooed up (shmoo=glue) it was time to grind the hull and fair it out. To fair a hull is not only to make it smooth, but also to remove the high and low points, making a perfect curve.  Here too we diverged from shop norms.  We only did a rough fairing and filled the low spots with thickened epoxy.  We did this because the silica (a high density/high strength thickening agent) in the glue is so difficulte to grind off, and the cedar so easy, that its pretty hard to do a perfect job.  To get around this we are going to do the final fairing on the last layer of veneer cold molded to the boat (there will be 4 layers of veneer on top of the strip planking).  This takes a lot less effort because the thickening agent in this last batch of epoxy is made of low density micro balloons (sounds like fun, huh!).  Micro-balloons have a hardness much closer to cedar than silica, and thus, its easier to achieve a fair surface. 

The photo above shows the strip planks of the boat.  A plank is a piece of wood that runs from stern to bow. The planks you see in this picture comprise the bottom-most layer of the composite structure--meaning that this is the foundation for 4 more layers of wood that will be glued on top.  

Definitions:

Scarf: to glue two lengths of wood together--this makes two short boards into one long board.

Scarf jig: Not a dance, contrary to popular belief.  A jig is something we build to fit onto a power tool so that it can perform a more specific function, requiring less thought and yielding a higher production. In this case, a jig is fitted to a miter-saw, allowing us to cut lengths of wood at exactly the same angle each time. These are later glued together or "scarfed"--which is why it is called a "scarf jig."


Bead and cove: a "ball and socket" joint--just like your hips!

Athwartship: From port to starboard--or the entire width of the ship.