05 November 2009

The Essential Boat Building Tool

For about 54 years, I was an unhandy guy. There was nothing I could do about it, it wasn't my fault, it was just the way my genes were wired.

So, while Helena could spend a pleasant afternoon refinishing our 100 year old iron windows -- scraping away rust, cutting glass to replace broken panes, and carefully puttying them in place -- my jobs were exercises in frustrating futility.

My jobs always went wrong. I always had to rework them and every job took longer than it should have or -- more correctly -- longer than I wanted it to.

And the faster I worked, the more of a hash I'd make of the job, and the longer it would take.

Absolute, utter frustration.

Then, a couple years ago, Helena asked me to fix our bedroom door which had somehow changed shape so it was impossible to close. For some reason, I decided that instead of trying to rush through the hated task, I'd take whatever time it took to do the job properly, and I wouldn't allow any interruption.

Surprise, surprise, not only did I fix the door, I actually enjoyed it. I suddenly realized that I could probably do any type of handyman job, no matter how complex, as long as I did it slowly enough.

In other words, the most important (and unused) tool in my toolbox was patience.

That epiphany led me directly to building this boat and to the problem of the too-large mold in front of me. I must admit I considered pretending that my plans had been drawn to the outside of the plank... would it really matter if the boat was 7/16ths of an inch wider on each side?

But in the end, patience -- and the will to build Cabin Boy the right way -- won out and I got down to the task of reworking my beautiful mold.

The mold inset by the width of the side plank and bottom
Photo by jalmberg

The photo above shows the goal -- to inset the mold from the lines of the body plan by the width of the side planks (7/16") and the bottom planks (5/8"). To do so accurately is a simple job. You just need to remember to do it!

How to inset body plan by width of planking
Drawing by jalmberg

The trick is to set a compass (the two-legged type you use in school), to the width of your side planking. In my case, 7/16". Then put the pointy part of the compass on the body plan line, and draw an arc on the inside. Do this every few inches along the whole side, and then connect the peaks of the arcs with a straight edge and pencil. 

Repeat on the other side using the same compass setting, and on the bottom using the width of the bottom planking (5/8" in my case). Connect all the arcs, and your body plan is now inset by the width of your planking.

Of course, you have to do this for the body plan at all stations. It's easy work and it goes quickly, but the number of lines on your lofting board doubles and gets confusing fast.

I decided to use different colored pencils for each of the 4 inset body plans. I was also careful to label each station, putting the number of the station in each corner of the inset body plan. This reduces (but doesn't eliminate!) the danger of using the wrong line.

So, I re-cut my mold to fit the new, inset plan, and assembled it on the lofting board again:

Re-cut mold, back on lofting board
Photo by jalmberg

Here is where I made yet another error. They say you can't teach experience, but I mention this mistake so perhaps you won't make it...

After re-cutting the mold and assembling it on the lofting board (to make sure all the lines and angles are correct), I removed it to put the bottom piece (called the 'cross spall', I've recently discovered) back on.


It is hard to see in the photo above, but there are 3 very important lines that cut through all of the molds:
  1. the horizontal 'sheer line'
  2. the horizontal 'load waterline' (l.w.l.)
  3. the vertical 'center line'

The forgotten lines
Drawing by jalmberg

Before removing the mold from the lofting board, I should have carefully marked each line on the mold. I would need them later.

Of course, I was impatient to finish the mold, so it wasn't until I was admiring my re-assembled mold for the second time that I remembered the much needed, but missing lines.

And that's when I pulled my shiny new tool out of my tool box. I was pretty sure my patience would be thoroughly broken in by time I finished this project.

>> Next Episode: I Am Bitten
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-- John


  1. So very, very true. I have sometimes wondered whether IT (or its clients!) creates or just attracts people who strive to get everything done as fast and efficently as possible with as little repetition as possible - but in either case, many of us are like that. Must dig my own 'patience' tool out and get through sawing out all the little bits to progress my own tender (much simpler than yours!).

  2. Patience is indeed the best tool in the kit. Yet, there are still times that I throw it on the floor and kick it's butt across the room.

    Then, I pick it up, clean it off, give it a hug and do the work right.

    From one computer enginerd to another, it's good to see you're enjoying this unlikely work.


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