that other types of land contact means such as tires or the like may be used and although not shown herein are considered within the spirit and scope of the invention as are drive motors such as hydraulic motors normally used to drive the powered drive gears 38 tires or other means of land contact a preferred propulsion system s utilizes the same engines to drive during both water borne and land borne operation this can be accomplished by use of a multi output transmission attached to a propulsion engine s in the preferred embodiment of the instant invention the outputs of the transmissions drive either a water propulsor 31 or a hydraulic pressure generator the output of the hydraulic pressure generator in turn drives a hydraulic motor that drives a drive gear in a track drive a tire or other means of power transmission while the propulsion system other than external portions of one type of water propulsor are not shown it is considered well within the spirit and scope of the instant invention fig9 shows a bottom plan view of the instant invention amphibious marine vehicle 30 with its land drives 36 37 retracted up for waterborne operation on its starboard side and down for land borne operation on its port side these arrangements are made for purposes of illustration since the land drives 36 37 are normally up or down dependent upon if the instant invention marine vehicle is in its water borne or land borne mode water inlets 32 of the water propulsors 31 are also shown fig1 presents a starboard side view of a trimaran 51 incorporating the instant invention that is shown in its waterborne mode of operation here an advantage.