An advisory system of a vessel that monitors variables of a vessel system inclusive of systems and subsystems that are used to operate the vessel. The advisory system may use machine-learning to learn from an operator (i) whether or not two variables are related to one another, and (ii) likelihood that a variable will reach a threshold, and, optionally, time until reaching the threshold. The system may receive operator feedback (i) to indicate whether the two variables are related to one another, and (ii) whether a behavior of the variable is normal or not normal. Thereafter, if a determination that the same two variables are related to one another and behaving in a similar manner, provide notification to the operator of the behavior. In response to determining that the variable is behaving (e.g., trending) in a similar manner that is not normal, providing a notification to the operator.

The propulsion unit includes a frame construction having an upper portion forming a support arm protruding from a hull of the vessel and a lower portion forming a longitudinal compartment provided with a propeller shaft having at least one propeller attached thereto, and a first electric motor driving the propeller shaft. The method includes measuring vibrations of the propulsion unit with at least one measuring device, forming a first auxiliary torque control signal based on the measured vibration signal, adding the first auxiliary torque control signal to a first torque control signal produced by a first torque controller of the first electric motor. The first auxiliary torque signal acts against the measured vibrations.

The propulsion unit includes a frame construction having an upper portion forming a support arm protruding from a hull of the vessel and a lower portion forming a longitudinal compartment provided with a propeller shaft having at least one propeller attached thereto, and a first electric motor driving the propeller shaft. The method includes measuring vibrations of the propulsion unit with at least one measuring device, forming a first auxiliary torque control signal based on the measured vibration signal, adding the first auxiliary torque control signal to a first torque control signal produced by a first torque controller of the first electric motor. The first auxiliary torque signal acts against the measured vibrations.

A method of making a propeller includes forming the propeller to have blades coupled to an outer hub, the outer hub coupled to an inner hub via ribs, and the inner hub configured to be coupled to the marine vessel. The ribs each have first and second ends with a midpoint therebetween, an inner end and an outer end that define a width therebetween, and a leading surface and a trailing surface that define a thickness therebetween. The ribs are tapered such that the thickness is greater at the midpoint than at least at one of the first end and the second end, and scalloped such that the width is greater at the midpoint than at least at one of the first end and the second end. Each of the ribs is coupled to the outer hub in radial alignment with one of the blades.

A method of making a propeller includes forming the propeller to have blades coupled to an outer hub, the outer hub coupled to an inner hub via ribs, and the inner hub configured to be coupled to the marine vessel. The ribs each have first and second ends with a midpoint therebetween, an inner end and an outer end that define a width therebetween, and a leading surface and a trailing surface that define a thickness therebetween. The ribs are tapered such that the thickness is greater at the midpoint than at least at one of the first end and the second end, and scalloped such that the width is greater at the midpoint than at least at one of the first end and the second end. Each of the ribs is coupled to the outer hub in radial alignment with one of the blades.

A watercraft with improved safety and stability is provided. The watercraft includes a shell defining a plurality of raceways for receiving water during certain maneuvers of the watercraft, thereby excerpting force upon the watercraft in a first direction. The shell is configured so as to prevent or otherwise inhibit the water from excerpting an opposed second force upon the watercraft. An intermediate panel of the shell provides increased flexibility, thereby serving as a shock absorber for the watercraft.

A watercraft with improved safety and stability is provided. The watercraft includes a shell defining a plurality of raceways for receiving water during certain maneuvers of the watercraft, thereby excerpting force upon the watercraft in a first direction. The shell is configured so as to prevent or otherwise inhibit the water from excerpting an opposed second force upon the watercraft. An intermediate panel of the shell provides increased flexibility, thereby serving as a shock absorber for the watercraft.

A catamaran lifting apparatus is disclosed for lifting objects in a marine environment. The apparatus includes first and second vessels that are spaced apart during use. A first frame spans between the vessels. A second frame spans between the vessels. The frames are spaced apart and connected to the vessels in a configuration that spaces the vessels apart. The first frame connects to the first vessel with a universal joint and to the second vessel with a hinged connection. The second frame connects to the second vessel with a universal joint and to the first vessel with a hinged or pinned connection. Each of the frames provides a space under the frame and in between the barges that enables a package to be lifted and/or a marine vessel to be positioned in between the barges and under the frames. In this fashion, an object that has been salvaged from the seabed can be placed upon the marine vessel that is positioned in between the barges and under the frames.

A catamaran lifting apparatus is disclosed for lifting objects in a marine environment. The apparatus includes first and second vessels that are spaced apart during use. A first frame spans between the vessels. A second frame spans between the vessels. The frames are spaced apart and connected to the vessels in a configuration that spaces the vessels apart. The first frame connects to the first vessel with a universal joint and to the second vessel with a hinged connection. The second frame connects to the second vessel with a universal joint and to the first vessel with a hinged or pinned connection. Each of the frames provides a space under the frame and in between the barges that enables a package to be lifted and/or a marine vessel to be positioned in between the barges and under the frames. In this fashion, an object that has been salvaged from the seabed can be placed upon the marine vessel that is positioned in between the barges and under the frames.

A viscous-drag-reducing cladding for a ship's hull whereby the wetted area of the hull is reduced by interspersing air between the hull surface and the water. A substantial portion of the submerged area of the ship's hull comprises densely packed air pockets. The dimension of the air pocket is less than twice the capillary length of water. Each air pocket is supplied with pressurised gas by means of a restrictor. The pressurised air is supplied to each air pocket by means of a network of corrugated channels.