Seam Batten Insomnia

IMG_2665For the last two weeks I have spent many sleepless hours worrying about making the new seam battens for my 1948 Speed Liner.  Seam battens provide a horizontal base into which to screw adjacent hull side planks.  They are mounted onto the hull frames, which run vertically, and inset into dado notches.  I’m not sure why this stressed me out so much, other than that it would require me to not only cut up one of my new African mahogany planks to make the battens, but also to cut the dado notches into the frames.  It felt kind of like preparing to perform surgery on myself.  Not having done this before, I wanted to make sure I did it right.  So, after much planning and measuring and teeth gnashing, I finally got up the nerve and dug right in.   Full speed ahead, boys!  Damn the torpedoes!

IMG_2647To make the seam battens I ripped four 10′ long, 1-1/2″ wide strips from the 1/2″ thick African mahogany, and then sanded them with 80 grit sandpaper.  I cut a short piece about 2″ long from the end of one of the new seam battens to use as my template for cutting the notches into the frames.  Presently, the boat has only two planks per side, each of which is approximately 9″ wide.  Because I couldn’t get new mahogany boards wide enough to make 9″ planks, and because narrower planks would bend to fit the shape of the boat more easily, I decided to split the difference and replace the two 9″ wide planks with four 4-1/2″ wide planks per side.  I made the battens 1-1/2″ wide so as to allow a 3/4″ wide area into which to screw each adjacent plank.

IMG_2653

I measured from the center of the existing seam batten into which the old planks had been fastened to a point 4-1/2″ above.  Then I marked horizontal lines on the frames 3/4″ above and below this line.  I confirmed the correctness of the width by comparing it to the 2″ template piece I had cut from one of the battens.  Then I measured and re-measured and re-measured again until I was absolutely certain I had my marks in the right place.  Did I mention that I was nervous about doing this?  Did I mention that I had not been sleeping?

Next I wrapped a piece of red electrical tape around the saw’s wood flush cut blade at the 1/2″ mark so I would be able to tell when I had sawed deeply enough.  Once my confidence reached a sufficient level I cut my first notch.  I cut into the frame to a depth of 1/2″ at the top and bottom edges where I had marked, and then cut multiple interim marks approximately 3/8″ apart.  Finally, I cut vertically down the back side of the notch at the 1/2″ point.  After that, the wood chunks came out quite easily.  I used a sharp chisel to clean up any debris or rough edges.

IMG_2658Once I had cut out all the notches I test fitted one of the seam battens and was pleased to see that it fit perfectly!  With this success under my belt I have overcome my stress and am now anxious to get the rest of the planks removed and to make the notches for the remaining seam battens.  Because of the shape of the boat I will have to cut the ends of this top batten at an angle such that it kind of feathers into the sheer clamp.  But, I’ll figure that out tomorrow after I’ve had some sleep.

Double Jack Rocks!


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