There are many considerations that go into the design of a human-powered submarine, but the two most important are speed and control. The speed of the submarine is determined by the mechanical efficiency of the drive system and the drag. The controllability of the submarine results from the design of the control surfaces and the control actuator. In a one-man sub, both of these systems are at the mercy of the pilot. It is very difficult for the pilot to concentrate on peddling at the correct rpm and make directional corrections at the same time. In many cases the pilot will stop or slow peddling in order to make control changes. This results in a decrease in the forward velocity of the sub. A better solution to controlling the submarine is to decrease or eliminate the need for the pilot to control the direction of the sub. This is the approach that was adopted last year at Virginia Tech.