Captain's log supplemental "Two Hulls One Motor =("

"Two Hulls, One Motor =("

And now a note on why having only one motor on a catamaran sucks.
Sailboat rudders are located at the back of the boat. This means that unlike a car, a sailboat turns by pushing its stern out either left or right. Basically, as water moves past the rudders they produce areas of high and low pressure as they turn either left or right. As the helmsman (person driving the boat) turns the wheel, the rudders move to one side. Doing so they create higher pressure on the outside face of the rudder. This causes the stern of the boat to be pushed away from the direction of the face of the rudder with higher pressure . (ie. the one deflecting the water). This is all well and good, but just like in a car, the road or in our case the water must be moving under us in order for the rudder to have any effect.
A catamaran is kind of like two monohulls attached by a central platform. We have two of everything underwater. Including two rudders and two propellers being driven by two motors. In catamarans, the motors are located in the stern of each hull. This allows for enviable agility.
Unlike a monohull, This can really get dramatic when we put one motor in forward and one in reverse. by doing this we can quite literally "spin on a dime".
This is all well and good and can make us look very good when we come in to a tough docking situation, but it assumes you have both motors.
In our case we are missing our starboard motor. This means that it is impossible to go from a standstill to a left hand turn. In fact, it means that by engaging the one (port) motor we necessarily start to turn in a circle to starboard. This starboard circle continues until we have created enough motion through the water to allow the rudders to compensate for the unevenly distributed thrust from the one motor. The problem is also the same in reverse. We are unable to turn to port while in reverse. at least not until we are moving at a pretty good clip.
All this is not that big a deal with some good planning and communication with dock masters (and each other), we've done all right. The one exception being in Charleston SC. There we had a very tight dockage, high currents high wind pushing us into the maze of docks and away from the slip we were trying to get to.
The upside to having only one motor is you use about half as much fuel, the boat is quieter, and quite surprisingly we actually go almost as fast as with two motors.