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Wednesday, November 13, 2019

Stability of a Sailing Kayak :: physics kayak sport sports

"Strippers" they are often called, relate to the method of boat building is old and well perfected. It basically involves setting up a series of molds and then wrapping strips of wood around them. More specifically, I'm mostly using the method outlined in the book Kayakcraft which is a great set of instructions for anyone wanting to take on this type of project. The wood for this boat is clear cedar that has been ripped into 3/4" x 1/4" strips. Each of those then get a concave and convex edge. This a great method because then each strip fits together perfectly at any angle seen on the plans. The molds and raised construction surface are all made of particle board. It's cheap and easy to work with but you have to make sure it doesn't get wet. You can see in the photo how the strips fit over the molds. Eventually, all the wood inside and out will be coated with a clear epoxy over fiberglass which ultimately will provide most of the strength and all of the water resistance. The sail plan is going to be quite simple but could consist of either 1 or 2 sails. Each option has its benefits. Dividing the load of the wind between two sails would lower their center of effort and therefore lower their leverage on the boat. But, these are fairly small sails to begin with and, aerodynamically, larger sails are generally more efficient. So while having two sails would increase my stability, having one would likely increase the performance. The option I will likely choose will be two large sails that can be easily reefed (or taken down). Then you could travel with one, or both if the wind was light. This problem can be thought of as one of rotational motion due to force. As the wind pushes on the sail, the buoyant force and keel mass push in the opposite direction. So, if we can define all of the forces acting on the system, we should be able to say something about how the boat will react at certain wind speeds. One problem in determining the wind speed necessary for capsize is the changing function of this system's center of mass, particularly the people inside. Most boat models involve boats that are much more massive than their passengers but mine will weigh around 75 lbs and carry 2 passengers. Stability of a Sailing Kayak :: physics kayak sport sports "Strippers" they are often called, relate to the method of boat building is old and well perfected. It basically involves setting up a series of molds and then wrapping strips of wood around them. More specifically, I'm mostly using the method outlined in the book Kayakcraft which is a great set of instructions for anyone wanting to take on this type of project. The wood for this boat is clear cedar that has been ripped into 3/4" x 1/4" strips. Each of those then get a concave and convex edge. This a great method because then each strip fits together perfectly at any angle seen on the plans. The molds and raised construction surface are all made of particle board. It's cheap and easy to work with but you have to make sure it doesn't get wet. You can see in the photo how the strips fit over the molds. Eventually, all the wood inside and out will be coated with a clear epoxy over fiberglass which ultimately will provide most of the strength and all of the water resistance. The sail plan is going to be quite simple but could consist of either 1 or 2 sails. Each option has its benefits. Dividing the load of the wind between two sails would lower their center of effort and therefore lower their leverage on the boat. But, these are fairly small sails to begin with and, aerodynamically, larger sails are generally more efficient. So while having two sails would increase my stability, having one would likely increase the performance. The option I will likely choose will be two large sails that can be easily reefed (or taken down). Then you could travel with one, or both if the wind was light. This problem can be thought of as one of rotational motion due to force. As the wind pushes on the sail, the buoyant force and keel mass push in the opposite direction. So, if we can define all of the forces acting on the system, we should be able to say something about how the boat will react at certain wind speeds. One problem in determining the wind speed necessary for capsize is the changing function of this system's center of mass, particularly the people inside. Most boat models involve boats that are much more massive than their passengers but mine will weigh around 75 lbs and carry 2 passengers.

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