Design Odds and Ends

Well now that the construction of Bolero is completed, obviously the design phase is over. But in cleaning up my files I ran across some information that I don't think I posted so I am adding here for posterity. Much it may be a bit cryptic as it was my quick and dirty pre-design work.

I started out summarizing all the information that I could find on the Shields design. This a summary of the principal dimensions of the Shields and some of the calculation that I performed to determine the viability of this project.



Part of these calculations are left over from an early concept when I thought I would have an electrical system and a high capacity bilge pump. Cost, weight and simplicity requirements bumped that early on. I had also decided to maintain the Shields existing water tight bulkheads and this combined with a water resistant cabin created, what I felt, was a much safer Shields. So these choices help remove the need for high capacity pumps.

For pure informational purposes only, I plugged the Bluenose, the Shields and the Atlantic Class (an early option for this conversion) sailboats into various formulas to get a feel for how they compared to each other.



I did this completely for fun. I don't have any first hand experience on the validity of any of these factors.

One of the thing I look hard at throughout Bolero's conversion was sailing ability. To that end I compared the sailing characteristics of my old Bluenose with my estimate of the final version of what Bolero would become. My initial plan was to keep Bolero's weight change below 20% or about 920 lbs. This number is a bit arbitrary, although I have read some references to support it, but it is also quite a bit below the PHRF stated crew weight of 1,260 lbs. My goal was to keep Bolero from beefing up during this conversion in any way that would significantly reduce her sailing performance.



I was impractical, if not impossible, to determine the exact difference between the weight removed from Bolero (which was surprising large) and the weight added with the cabin and cockpit modifications. Even so, Tim and I have a pretty good feeling that any weight gain should be modest. I also think I have enough information to determine an approximate weight gain from how Bolero floats on her lines. Time will tell.

My goal is to continue studying sail combinations and wind performance so I can provide the simplest sail combination that allows Bolero to sail in the widest variety of wind ranges (I don't really enjoy rowing).

Over the three years that I have been planning and research for this conversion I have compared the sailing and physical parameters of many, many sailboats. Mostly they have been older, and sometimes wooden, classics. This is a very brief summary of some of these.



The Cape Dory Typhoon is there because she was the runner up during my last boat purchase (the Bluenose Sloop won out). I compared everything to the Bluenose to help get an idea of what was similar and what was different.

The Atlantic Class One Design was actually first on my list for this conversion. And I really like this design. But since I didn't have access to either of these boats I had to perform three dimensional pre-design and mock-up sketches and drawings to determine the viability of succeeding with the Shields or the Atlantic hull. In quickly became apparent to me that the Shields had a great margin of safety in achieving my goals. The Atlantic had even less freeboard and her mast is even further aft. I won't say it would have been impossible but I was struggling to find a way so the Shield won out.

As request, here is a pretty current sail plan and deck plan for Bolero.