गुरुवार, 29 जनवरी 2015
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Over The Hump
Its become something of a joke between Helena and me. More times than I want to remember, Ive marched triumphantly up the stairs from my basement workshop and announced, "Im over the hump! Ive just finished what must be the hardest part of building this boat. Its all down hill from here! Yahoo!"
I said it when I finished lofting the plans, when I finally got up enough nerve to buy some real wood, when I finally got up enough nerve to actually cut that real wood, when I figured out how to mount Cabin Boys stem and transom (oh, bitter irony!), when I figure out how to cut the stem rabbet, when I finally learned how to spell rabbet, etc., etc.
I said it again just last week, when I had both garboard planks bedded and fastened. "That was the hump," I announced. "Everyone says the garboards are the hardest part. Its all down hill from here! Yahoo!"
And who can blame me? Spiling those garboards really was hard. Such a complex shape and such a demanding technique. The rest of the planks looked simple in comparison. A slam-dunk, as intelligent people used to say.
I should have known better!
On my first attempt at spiling the second plank, I was so confident that I ignored my own advice and tried to spile the hood end, rather than using a pattern.
I figured a little audacity was justified. Id already mastered the art of spiling, after all. Why keep making hood-end patterns if you could spile them, instead? It was worth a try, I figured.
The result? Disaster, of course. After unspiling the points I ended up with a pattern for the second plank that didnt fit at all. Not even close!
No problem, Id just do it again.
"Im finally over the hump," I mentioned casually. "Its all down hill from here."
"Yahoo!" she said, with a smile.
>>> Next Episode: Swedish Furled Foam
I hope youre enjoying "The Unlikely Boat Builder" as much as I enjoy writing it. Some people have asked for a way to be notified automatically when I post new episodes. Ive figured out how to do this, so if youd like to be notified, please click on the link below. I promise Ill never spam you (and Google will have my head if I do.)
Thanks for your interest!
-- John
Over The Hump
Its become something of a joke between Helena and me. More times than I want to remember, Ive marched triumphantly up the stairs from my basement workshop and announced, "Im over the hump! Ive just finished what must be the hardest part of building this boat. Its all down hill from here! Yahoo!"
I said it when I finished lofting the plans, when I finally got up enough nerve to buy some real wood, when I finally got up enough nerve to actually cut that real wood, when I figured out how to mount Cabin Boys stem and transom (oh, bitter irony!), when I figure out how to cut the stem rabbet, when I finally learned how to spell rabbet, etc., etc.
I said it again just last week, when I had both garboard planks bedded and fastened. "That was the hump," I announced. "Everyone says the garboards are the hardest part. Its all down hill from here! Yahoo!"
And who can blame me? Spiling those garboards really was hard. Such a complex shape and such a demanding technique. The rest of the planks looked simple in comparison. A slam-dunk, as intelligent people used to say.
On my first attempt at spiling the second plank, I was so confident that I ignored my own advice and tried to spile the hood end, rather than using a pattern.
The Chutzpah of Hope
photo jalmberg
I figured a little audacity was justified. Id already mastered the art of spiling, after all. Why keep making hood-end patterns if you could spile them, instead? It was worth a try, I figured.
The result? Disaster, of course. After unspiling the points I ended up with a pattern for the second plank that didnt fit at all. Not even close!
No problem, Id just do it again.
Second try, with humility...
photo jalmberg
The second time, I carefully cut out a hood-end pattern, and made extra, extra sure that the batten wasnt edge-set. The formula was simple:
Perfect Technique = Perfect Pattern
But again, after unspiling the points, the resulting pattern fit like an unruly banana, curving in the wrong direction. Clearly, I was doing something wrong, but what?
After a long session in my thinking chair, I decided that the problem must have something to do with the angle of the batten. My narrow battens lay directly on the forms, whereas the full-size pattern lay on the beveled garboard.
Shimming the spiling batten to the right angle
photo jalmberg
My first thought was to use a kind of shim to tilt the spiling batten to the right angle... But I lost faith in this approach even before finishing the shimming process. It was just too easy to twist the narrow luan plywood battens into the wrong shape. And once removed from the forms and laid flat on the pattern stock...
I was onto something with the shim idea, but the resulting shims + batten system was just too flimsy... I just knew it wasnt going to work...
But I suddenly knew what would work!
The secret to happy spiling -- wide battens!
photo jalmberg
I tossed the narrow spiling batten into my kindling box, and cut out the widest 3-part spiling batten that would fit between the lap lines.
This spiling batten was wide enough to lay on the garboard bevel, just like the plank would have to. So the batten would lay on the forms at the same angle as the plank would. This angle, I reasoned (hoped?), was vital to accurate spiling.
Well, there was only one way to find out...
The unspiled, cutout pattern for the second plank
photo jalmberg
Success! The unspiled pattern fit perfectly. It followed the laplines, both top and bottom, and lay flat on the forms, with no edge setting.
Phew!
Once you have an accurate pattern, the rest is simple.
Second plank, with gains cut
photo jalmberg
I traced the pattern onto my sheet of marine plywood, cut the plank out with a jigsaw, and remembered to cut the gains. I tried it on the forms, and it fit perfectly.
Suddenly, the three failed attempts at spiling this simple plank faded into distant memory. All that remained was that glorious, close fitting plank, glowing under the rich, warm basement lights. Was that a heavenly chorus singing its praises? Or a Pringles jingle on the TV? No matter...
With the second row of planks screwed and glued, I climbed up the stairs and found Helena behind her piano.
Suddenly, the three failed attempts at spiling this simple plank faded into distant memory. All that remained was that glorious, close fitting plank, glowing under the rich, warm basement lights. Was that a heavenly chorus singing its praises? Or a Pringles jingle on the TV? No matter...
With the second row of planks screwed and glued, I climbed up the stairs and found Helena behind her piano.
"Im finally over the hump," I mentioned casually. "Its all down hill from here."
"Yahoo!" she said, with a smile.
>>> Next Episode: Swedish Furled Foam
Get Notified Automatically
I hope youre enjoying "The Unlikely Boat Builder" as much as I enjoy writing it. Some people have asked for a way to be notified automatically when I post new episodes. Ive figured out how to do this, so if youd like to be notified, please click on the link below. I promise Ill never spam you (and Google will have my head if I do.)
Thanks for your interest!
-- John
Get notified automatically
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