Thursday, April 22, 2010

The Journey of the Stem


Sorry about the delay in postings. Although we endeavour to keep our followers informed, it sometimes seems like building can come to occupy blogging time. As we are tentatively planning to finish this craft by Summer, it seems as though we need every opportunity to work that we can. Anyways, significant progress has been made since the purchase of materials, and the stem is now completed.
Stem Pieces and Templates
As mentioned previously, we decided to build the stem out of three laminated mahogany layers. By doing this, we hoped to achieve the required 2.5" while still keeping weight (and costs) down. The adhesive of choice for this task was System 3's G2. Originally used to construct aircraft, and designed to have superior joint strength and flexibility, we figured that it would be ideal for the task. Anything that can be trusted to keep a plane in the air is definitely good enough for a little knockabout sailboat. In addition, this stuff has incredible open time--it will remain workable for up to 4 hours after preparation! This is extremely useful when one needs to glue several joints (eg all of the scarfs for the planking), as it does not place pressure on expedience, which ultimately leads to mistakes. Because Atkin specifies a 2-piece stem in the drawings, we had a total of 6 pieces to cut out and keep track of. After roughing components to size with a jigsaw and finishing with a router and template, we epoxied them to form the finished stem. A 2.5" thick stem is truly formidable when completed! As the mahogany we selected is fairly hard, we are confident that the stem will handle any abuse it might face. Another step in the journey of building a boat!

Glue-up of the Stem

The next challenge was that of the stem rabbet--a daunting task to first time builders, as a mistake here can tarnish a beautiful piece of wood. Problematically, the plans do not illustrate the rear delineation of the rabbet-the bearding line. Although we had a general idea of the position of the stem line (the front boundary of the rabbet), the bearding line was a bit of a mystery. However, after some puzzling over the plans and reading others' accounts of this step, we found that, in fact, the process used to determine this line is fairly straightforward. From the overhead view of the craft in the plans, which defines the angle at which the planking meets the stem, it is possible to use trig to complete the calculation. Knowing the width of the planking and the angle, one can find the hypoteneuse (the distance between the bearding and stem lines) at both the top and bottom of the craft. From here, a batten between the lines lends the shape the rabbet must take. For a more in depth account of this process, I highly reccommend the Unlikely Boatbuilder's blog. Finally, our preparations for the build have paid off! Using a mallet, a few sharp chisels and a fid (a small piece of wood the same dimensions as the planking), the stem rabbet can be cut. I know that it's frustrating that all the books leave it at this, but it is a process that is much easier to experience than to explain. Being sure to make careful, conservative cuts and checking progress with the fid often will ensure a tight fitting rabbet. It truly is not as difficult as it may seem.

Rivets and Roves for the Hull
316 Stainless--Pricey Stuff!
Lastly, while on vacation, we obtained our required hardware from Jamestown. With this and a completed stem, there is little that still stands between us and planking. Dauntless, we shall press forward into the realm of spiling battens, lap bevels, gains, and much more.


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