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Pocketship Free Flooding Keel?
So I am building a model of Pocketship in anticipation of starting on a full size version in the Spring. I notice that the aft part of the keel construction is a hollow box - a sealed air chamber below the water line. I understand the reasoning that you would not want to fill it with lead as that would make the boat too heavy in the stern. But the idea of having a sealed air chamber completely submerged is just inviting trapped moisture and a place for rot to start. What would be the downside of making the aft keel section free flooding and moving some of the lead ballast from behind the centerboard to in front of it to compensate for the loss of buoyancy aft? A free flooding keel would allow air circulation inside the keel section and give it a chance to dry out.
1 reply:
RE: Pocketship Free Flooding Keel?
» Submitted by John, CLC - Mon, 12/8/08 » 5:29 PM
>>>>>>But the idea of having a sealed air chamber completely submerged is just inviting trapped moisture and a place for rot to start.>>>>>>
I gave that a lot of thought early on, but eventually decided not to make that space free-flooding. Almost 20 years ago I built a keel sailing boat like this with a similar hollow keel and a combination of lead and empty space. Those plans (a Bolger yawl) indicated that the empty areas be free-flooding. I couldn't bring myself to do it then---too many nooks and crannies for water to work into, and the flood/drain holes are draggy in the water. I can't prove it but I think the boat performed better without the extra weight out towards the ends of the boat.
So the stern section of the keel is to remain watertight. I wouldn't want to mess with the carefully calculated trim of the boat by erasing that flotation.
With epoxy and fiberglass, the likelihood of water getting into that space is nearly zed. (No more likely than water leaking into any other place in the boat---which you will work very, very hard to avoid.)