: You might be better off with a rudder as it will be further back from the
: center of the boat.

If I was absolutely sure I would add a sail to this boat a rudder would be my choice, otherwise I would like to keep it fairly simple.

: As I recall you have a short boat. For any given width (beam) tracking should
: improve as the boat is lengthened. it is a matter of leverage. The water
: that is pushed aside has a certain resistance to moving out of the way.
: When that resistance is at the end of a long lever it has more influence
: than when it is at the end of a short lever. Long boat means a long lever.
: short boat is a short lever.

: Consider the absolute worst in tracking: A donut-shaped innertube. Take a
: canoe paddle and sit in he middle of a floating innertube. As you paddle
: you won't get any propulsion to speak of. Instead you will spin like a
: top.

: Sitting on the middle of a telephone pole would be the other extreme. That
: would be very difficult to turn. Compare that to a canoe with two people
: in it (one at each end). It should be pretty obvious that the double has
: some distinct turning advantages over a canoe with a single paddler
: sitting at the middle of the boat.

: In between the donut shape and the pole shape are a considerable number of
: possible shapes, but generally, fatter lets you turn on a dime, and
: skinnier helps you go straight.

A very good and simple explaination that I clearly understand now.

: As for your boat, and why it loses some of its tracking when it is loaded. As
: I recall you designed your kayak so that as it sank deeper into the water
: it would become more stable. Did you widen the middle of the boat a bit in
: order to add some internal sponsons? I think your plan was that you would
: flood the boat to lower it in the water should you need to reenter. Well,
: it is possible that as the boat sinks lower in the water with added cargo
: the outline of the waterline of the boat becomes wider and wider as the
: boat sinks deeper and deeper. Effectively, your boat's outline changes
: with the added load, and presents a broader target for water resistance.

The boat was 28" wide and the sponsors fit right in ok with room for me to fit. And you have the reasoning right for the way it all works. And again I think you are right in that as the boat sinks deeper into the water and the with displacment get bigger and causes problems.

: Adding a rudder -- moveable or fixed -- or maybe even a fixed vertical fin
: carved to look like a fish fin - effectively increases the length of the
: boat, and gives a lever that is located further from the center fo the
: boat than a skeg.

Of the three skegs I made of foam and tested, the longest one really made a difference and I like it. I have a pattern set aside incase I want to use it. I like the idea of the retractable skeg so I can turn my boat like an intertube as you describe if I am in small creeks, etc. What I could do is to modify the retractable skeg to be 2' long so as to have the increased leverage for really good tracking but be able to retract it completely for turning on a dime. I guess the draw back would be drag along the long skeg tunnel.

: Just a thought.

: PGJ

Again thanks for you insites. It all makes sense to me.

Take care,
John