Abstract: An underwater excavation apparatus having various mechanisms for moving the underwater excavation apparatus that are provided on or adjacent to the apparatus is described. The mechanisms for moving the underwater excavation apparatus provide for orienting, positioning, rotating, counteracting reactive torque and/or steering the apparatus.

Abstract: The present invention relates to an underwater excavation apparatus and a method of excavation with the same. The apparatus of the invention performs the excavation by both mass flow and jet flow. Mass flow excavation takes place at a pressure that is lower than the jet flow excavation performed by the apparatus, and the volume flow rate of the mass flow excavation is greater than the volume flow rate of the jet flow excavation performed by the apparatus. The outlet for jet flow excavation is provided within the outlet for mass flow excavation of the apparatus.