We have developed a novel type of submersible called a Synergistically Propelled Ichthyoid [SPI] which is propelled by the combined jet action and oscillatory motion of a fluttering fluid-conveying tail. Two dynamic models for an SPI are presented and solved. An analytically tractable model presented in a previous work which assumes a submersible at constant velocity has been included as a reference point. A more complex model in a general planar reference frame is also presented and is solved numerically. These simulations show a benefit to using a fluttering tail relative to a dimensionally identical rigid tail. Results which show that the SPI can be turned by an appropriate choice of time-variable fluid velocity are also presented. Construction details of an experimental realization are provided. Preliminary measurements taken using that platform are also provided; these measurements qualitatively confirm the simulation's conclusion that a fluttering flexible tail is capable of higher speed than a dimensionally identical rigid tail.