the radial slots 144 houses a thrust mass 146 with each thrust mass 146 including opposing rollers 148 to allow the thrust mass 146 to move between the retracted and extended positions a spring 152 which is the same construction as spring 128 is positioned within each of the radial slots 144 spring 152 biases the corresponding thrust mass 146 into the second extended position again motor 114 functions to rotate the lower capture plates 142 and the associated thrust masses 146 in a second sense u201c b u201d that is counter to first sense u201c a u201d in the preferred embodiment three slots and three thrust masses are included in both the upper and lower sets of plates the counter rotation u201c a u201d vs u201c b u201d of the upper and lower capture plates 118 and 142 causes the thrust masses 124 and 146 to sequentially impact impulse ramp 116 in this regard the upper masses 124 contact the upper extent of ramp 116 while the lower masses 146 contact the lower extent of ramp 116 each of these collisions forces the corresponding thrust mass 124 and 146 into the retracted position notably the impact with ramp 116 forces the thrust masses 124 and 146 into the retracted position over the bias of the corresponding springs 128 and 152 as a result an impulsive force is transferred to ramp 116 and plate 112 and a corresponding forward motion is generated finally fig1 shows the device of the present invention installed upon an inflatable or buoyant device 162 fig1 shows the device mounted to a.