hydrophone sensitive to a particular underwater acoustic transmission for initiating detonation barge 10 could be deployed on a pre designed course or could be controlled from a remote location in the illustrated example system 100 is shown with a vehicle control signal receiver 32 which is coupled to jet propulsors 12 jato rockets 14 and steering mechanism 16 a remotely issued command control signal is transmitted to receiver 32 which activates jet propulsors 12 and if present jato rockets 14 and steering mechanism 16 jato rockets 14 are used initially to quickly take barge 10 to planing speed so that such planing is easily maintained by jet propulsors 12 and steered by steering mechanism 16 the number and placement of detonators 26 is such that at detonation a downwardly directed planar pressure wave results this is best illustrated in fig4 where detonation of explosive material 22 in one region 20 will be explained at detonation each detonator 26 is commanded to detonate its respective demolition charge if each detonator 26 is identically configured the initial pressure waves 40 from detonation of explosive material 22 radiating downward into explosive material 22 will be nearly identical further if detonators 26 lie in the same plane as shown and if each detonator 26 is detonated simultaneously or 34 nearly simultaneously 34 which is defined herein as being within a few milliseconds initial pressure waves 40 will coalesce to form a downwardly directed planar wave 42 moving down through explosive material 22 detonators 26 should be arranged in symmetrical units in region 20 this can be accomplished using a repeating triangle unit.