On Tue, 29 Apr 2008 10:53:50 -0400, Larry wrote:

Goofball_star_dot_etal wrote:

Give it a rudder so it can become the happy little second-order system
it was born to be.

Well, you can't add a rudder to a jet boat.

Try to remember that you sold that boat last year and want to control
a boat with a 15 hp Yamaha outboard at "trolling speeds (about 1 knot
or 1.5 mph)"!! with an autopilot which expects a certain (range of)
yaw rate proportional to the control input, not a pig dominated by
small forces and relatively large moment of inertia.