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Welcome to my blog on the building and sailing of a Goat Island Skiff (GIS). Join us on the Michael Storer Wooden Boat Plans forum or on Facebook, where the community of Storer Boat builders, owners, and admirers share their ideas, experiences, and watery hi-jinx.

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Sunday, May 1, 2011

Malus Pinus Radiata

My other wood butchery project yesterday was to cut the lumber for the mast.  The original design plans for the Goat Island Skiff called for making a solid pole not unlike the two spars.  After some years, Storer sat down and worked out a design for a hollow box section mast that is just as strong but weighs 45% less.  It too incorporates a tapered design, as much for the aesthetics as the weight reduction.
Each side of the box is to be made of a fairly thin plank.  Thin enough that no lumber supplier carries that dimension (less than 1/2” thick) on the shelf.  It is assumed that one  can have one’s lumber planed--or thicknessed--to the appropriate dimension.  And if one is working with a reputable lumber yard that carries fine quality wood, the assumption is valid.  Just add money and anything is achievable.  Of yeah, did I mention that the plan specifies Douglas Fir for the mast?  and that its finished length is around 16 feet?
Since I’m shopping from the aisles of a national big box chain of home centers, I had to be a little creative.  A discussion on the Storer Forum (started by a different builder doing the same parts) revolved around the use of Radiata Pine for the Goat’s spars.  Long story short, it was agreed that the mast’s robust design could compensate for the material’s properties, provided the Radiata was clear and tight.  Radiata is very abundant these days and is milled into very very clean 1-by dimensions (e.g. 1x3, 1x4, 1x6).  To those unfamiliar with lumber sizes, 1x4 is actually the measurement of the raw plank which when finished on all four sides becomes 3/4” x 3 1/2”.
Thankfully, the dimensions of the mast fit nicely within the stock board widths; only small amount of trimming is needed.

You’ll note in the photo above that I selected boards cut from the edges of the log as opposed to a center cut.  I feel this will match the stresses of the mast to the tree’s original stresses.  I these board try to warp, they will bow the mast’s diameter, but may still remain straight from top to bottom.
A bigger challenge was finding the right combinations to equal a 16-foot length, since the 1-by lumber comes in a maximum of 10 feet.  Plus, it’s not particularly cheap, so I want to minimize waste.  Here you’ll see a combination of 10- and 8-foot lengths of 1x4 and 1x3s respectively that will form the wide and narrow sides of the mast.

I would rather stagger the joints even more than shown here, but to do so will require adding more joints elsewhere.  They say that a well executed epoxy joint is stronger than the surrounding wood...
The biggest challenge of all was/is getting the thickness of the boards down to spec.  The “school solution” is to use (or pay someone to use) a planer or thicknesser.  I actually considered buying one, but they are over $200 and I really don’t see needed one in the future.  A router table on the other hand...
So I have a new router table which will serve this project--and the family in general--very well.  My silly thought was to simply run the stock over a wide flat bit in several passes.  I picked up a 3/4” bit and proceeded to work from the edges inward.  And that when it hit me... Um, what would I do to support the plank when the last of the material is being removed?  I don’t have jig or a shim to hold the work piece up at exactly the right height (something like 5.5mm) for the final pass.  So the solution was to not make that final pass.

I removed as much material as I could without having the work piece collapse onto the router bit (which protrudes upward from underneath the table).  Next, I will use a plane, or a saw, or a beaver looking for work, to trim off these remaining “rails” and leave me with the proper dimensions.
In truth, I could have--and possibly should have--altered the plan’s dimensions to accommodate the 3/4” boards and still retain the exterior dimensions of the finished mast.  Or I could have slapped the boards together to create a mast of larger width and then alter the rest of the build to accommodate the custom sized mast.  And I did consider both courses of action.  But a big part of the pleasure I get from projects like this is the problem solving, even if the problem is self-induced (I got myself into it, I’ll get myself out of it!).
So that’s where I’m at as of this writing.  I need to cut scarf joint angles in all these boards (including the ones from the previous post, Yard Work) to get the correct lengths.  Then they must all be assembled into their raw spar form.  Then they will have be shaped.  Then... the list goes on...


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