Underwater excavation apparatus

An underwater excavation apparatus, comprising at least one mass flow excavation means and at least one jet flow excavation means, wherein an outlet of the at least one jet flow excavation means is provided within an outlet of the at least one mass flow excavation means, and wherein, in use, at least one mass flow from at least one of the at least one mass flow excavation means is substantially parallel to at least one jet flow from at least one of the at least one jet flow excavation means.

An underwater excavation apparatus, comprising at least one mass flow excavation means and at least one jet flow excavation means, wherein an outlet of the at least one jet flow excavation means is provided within an outlet of the at least one mass flow excavation means, wherein the outlet of the at least one mass flow excavation means is substantially concentric with the outlet of the at least one jet flow excavation means, and wherein an inlet means to the outlet of the at least one jet flow excavation means is provided between an at least one impeller of the mass flow excavation means and the outlet of the mass flow excavation means and the outlet of the jet flow excavation means.

An underwater excavation apparatus, comprising at least one mass flow excavation means and at least one jet flow excavation means, wherein the at least one mass flow excavation means comprises a housing and at least one impeller provided within the housing, wherein guide vanes are provided within the housing to guide the mass flow, in use, and wherein an outlet of the at least one jet flow excavation means is provided within an outlet of the at least one mass flow excavation means.

An underwater excavation apparatus, comprising at least one mass flow excavation means and at least one jet flow excavation means, wherein the at least one mass flow excavation means comprises a housing and at least one impeller provided within the housing, wherein the housing comprises a hollow body, having an upper facing inlet and a lower facing outlet and wherein an outlet of the at least one jet flow excavation means is provided within an outlet of the at least one mass flow excavation means.

An underwater excavation apparatus, comprising at least one mass flow excavation means and at least one jet flow excavation means, wherein the at least one mass flow excavation means comprises a housing and at least one pair of impellers provided within the housing, wherein the housing comprises a hollow body having at least two inlets and at least one outlet, wherein the at least one pair of impellers are rotatably mounted in the hollow body, wherein the at least two inlets are substantially symmetrically disposed around an axis extending from the at least one outlet, and wherein an outlet of the at least one jet flow excavation means is provided within an outlet of the at least one mass flow excavation means.