Spiling

Batten along edge of garboard on my newly faired framework

Fairing is done, finally.  A layer of dust covers everything in my garage/ workshop from two weeks using the grinder to finish the fairing I started with the power planer.  Amazingly, none of those highly creative tool manufacturers, who can provide us with unlimited alternative ways to tighten a screw, seem to be able to figure out how to build dust collection into a good old 4 1/2 inch grinder.
Regardless, the task is finished, and I can proceed with making the garboard strakes.  

I worked slowly through the fairing process for several reasons:

First, it's important to get it right.  The appearance of the finished boat, the symmetry of the hull, and even seaworthiness are compromised by sloppy fairing.  

Second, it is springtime and the garden makes demands on my time.  Cleanup, tilling, planting, etc. are time sensitive and time consuming activities.  Can't wait until it is convenient to plant tomatoes.

Third, I outsmarted myself with my "just-in-time" material ordering.  While it has helped mightily in terms of cash flow, I had not anticipated a 38 day delivery delay on the okoume marine plywood I will use for planking.  The vendor has given me a shipping date of May 30, and while I have found another vendor who has some sheets in stock, their price is 40 percent higher.  I'll probably buy a couple of sheets this week at the inflated price just to get started, and tuck the experience away for future reference.

Spiling batten for garboard strake

Three o'clock in the morning is my time for inspiration.  (I think it is the result of physiological changes afflicting men of a certain age.)  Nevertheless, in one such moment of clarity and brilliance a few weeks ago, the idea of spiling instead of building pattern templates struck me.  I learned about spiling as a volunteer at the Workshop on the Water (WOW) at the Independence Seaport Museum in Philadelphia.  They use the technique routinely for planking new wooden boats as well as replacing planks in restoration projects.  While I have never seen the technique used in clinkerbuilt construction, and have not read of its use by other Grey Seal builders, nor in Iain Oughtred's book on glued plywood construction, there seems to be no reason why it would not work just as well. If you are not familiar with WOW, and are into wooden boat building, you will love their website, http://woodboatbuilder.com/.  



Spiling involves first clamping a wide batten along the entire length of the hull, in the center of the space  you want a plank or strake to fill. I used a 4 inch width of 1/4 inch plywood underlayment, which is cheap and ubiquitous.
Next, you draw a reference line across the spiling batten at the edge each mould.

Set the point of a divider precisely on the lower edge of the strake, and draw a short arc that intersects the mould edge line.  Do the same at the upper edge of the proposed strake.
Repeat this process for each mould, being careful to maintain a constant separation between the arms of the dividers.

Since you will need to reset the dividers to the same spacing you used when marking the spiling batten, make sure to mark the batten as shown in the picture.  If, as you move forward or aft, the width of the space forces you to reset the dividers, make sure to put another reference on the batten, noting to which moulds that spacing applies.
The next step is the transfer of the strake measurements to the planking material, which is, alas, the aforementioned overpriced okoume I have yet to buy.