Power train layout for an amphibious vehicle

An amphibious vehicle with a lateral centerline and a planar hull surface having outboard parameters, said planar hull surface comprising the base of said amphibious vehicle;

• said amphibious vehicle containing a prime mover having a crankshaft defining the axial centerline of said prime mover;
• a pair of waterjets each of said waterjets having an axial shaft defining a horizontal centerline and each of said waterjets having inboard and outboard sides, said waterjets located in said amphibious vehicle such that each of said waterjets' respective inboard sides is located immediately adjacent said lateral centerline of said amphibious vehicle, said waterjets contained in said amphibious vehicle such that said horizontal centerline of at least one of said waterjets is positioned relatively below said horizontal centerline of said prime mover;
• a propulsion gearbox mounted in said amphibious vehicle, said propulsion gearbox having a plurality of output shafts including a land transmission output shaft and a pair of waterjet output shafts;
• a land transmission mounted in said amphibious vehicle, said land transmission located forward of said propulsion gearbox and connected to said land transmission output shaft of said propulsion gearbox;
• said waterjets include a pair of inlet plenums connected between said waterjets and an inlet aperture through said planar surface on the underside of said vehicle, said inlet aperture located such as to be intersected by said lateral centerline of said amphibious vehicle, said inlet aperture significantly inboard of the outboard perimeters of said planar surface.

A power train arrangement for a high water speed amphibious tracked vehicle having a planar surface making up the bottom of said vehicle, which configures the major power components so that they do not determine the vehicle length, allowing the length to be optimized for land mobility and system weight, the power train arrangement comprising:

• a pair of waterjets placed on the vehicle center line whereby cavitation in said waterjets is minimized due to said waterjets not ingesting air, such air being more prevalent outboard of the general area of the vehicle center line, said waterjets further sharing mounting structure with other power train components;
• a waterjet inlet plenum straddling said vehicle center line, said inlet plenum including an aperture in said planar surface of said vehicle;
• an engine for driving said vehicle, said engine located in the vehicle in position generally above said waterjet inlet plenum whereby said engine placement serves to facilitate a short power train length and to locate the vehicle center of gravity rearward, said engine provided to drive said waterjets;
• a land transmission for use in propelling the vehicle when said vehicle is not being propelled by said waterjets;
• a propulsion gearbox connected to said engine, to said waterjets and to said land transmission.