50208RE: Re: [boatdesign] RE: Storm Petrel (Bolger's)
- Nov 26, 2013
Bruce:>>If I am not mistaken, the Marsh Duck is not ballasted. Where the Storm Petrel is ballasted with a steel plate fin keel. Normally, ballasted boats have a more gentle motion because of their higher mass.I think that claim depends on the size of the waves in relation to the boat. Also is valid only for boats of similar length and beam. But based on my experience and research, I suspect that Marsh Hen will have a gentler motion than Storm Petrel in waves, especially those 15 feet high or higher. I expect that to be true for smaller waves as well.>>I also think that part of the Bolger strategy of Storm Petrel was the very small cabin, which would allow the crew to brace themselves to avoid getting tossed around. 99.999% unnecessary, but 0.001% of the time you could survive a disaster this way.But what about the waves that come unexpectedly from an unlooked for direction, causing sudden actions? It is better to have a design that does not react in a violent manner to such waves.T. Lee.On Tue, Nov 19, 2013 at 11:55 AM, <nutty_boats@...> wrote:
Thanks, graeme, for the links.
A couple of the links answered a question I long had about Bolger, namely to what school of seaworthiness did he belong. There are two main schools that I know of, most designers ascribe to what I call the barrel over Niagra Falls school where it does not matter how violently the boat acts, as long as it stays in one piece, and the second one where the emphasis is placed on reducing the boat's motion as much as possible for given conditions through good design, because the boat's cargo, the soft, squishy crew inside, can take only so much motion before it is incapacitated, injured or killed. Apparently Bolger ascribed to the first school.
I go with the second school, and as such, Scot's Marsh Duck will have gentler motion than Bolger's Storm Petrel, hence I think it is a superior design.
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