This rig consists of a hollow Shark Fin with three separate ballast chambers inside to control and adjust its height in the water. Below is a speedrail frame for mounting weights to add side to side stability. Pulling the Fin with a rope provided all the necessary propulsion. Turns were achieved by mounting a 20 foot pivot arm off the side of the FinÕs speedrail frame the end of which was held still while the Fin was pulled in a arc.