A port-hole of an immersed structure, for seeing, from inside the structure in air, to the outside of the structure in water, level with the structure, wherein the face of the port-hole oriented toward the inside of the structure includes at least one flat section forming an angle of 20 to 40° with respect to the face of the port-hole oriented toward the outside of the structure.

An assembly in a marine vessel includes a unit arranged in a water tight chamber opening in a hull of a vessel, wherein the unit is adapted to extend into the water below the vessel when at a mounted position. A connection path between an inside and an outside of the vessel is provided with a sealing system and the sealing system divides the connection path into an outside connection path portion and an inside connection path portion. The assembly includes a gas inlet system opening to the outside connection path portion.

A cycloidal marine propulsion unit, including a hollow rotary casing having a central axis and defining a central inner space with an opening at an axial end thereof. A mounting body rotatably supports the rotary casing on a hull of a marine vessel. A rotating arrangement is provided for rotating said hollow rotary casing, while a plurality of blades extend axially from the rotary casing away from the hull. Each blade is mounted for pivotal movement with respect to the rotary casing, about respective blade axes. The rotating arrangement is configured to rotate the rotary casing by a circumference thereof. A blade shaft portion of each blade is at least partly received within the central inner space so as to attach said blade to the rotary casing.

A method for the maintenance of a ship or platform propulsion assembly includes providing a hull insert forming a watertight housing located within a hull of a ship except for an opening. A motor is in the hull external to the housing and a thruster is external to the hull. A telescopic driving shaft sealingly passes through one of the walls of the housing to operatively connect the motor and the thruster to transmit movement to the thruster. Moving the thruster includes retracting the thruster into the housing through the opening. A separable submersible movable hatch is lowered by removable hanging cables. The submersible movable hatch externally engages the housing and sealingly closes the opening to close the housing and form a watertight closed chamber. Fluids within the closed chamber are evacuated even when the hull is floating and partially submersed, with the thruster at least partially in air.

A water intake system for a boat spray gun, including a system utilizing a port through a transom of a boat, the port positioned proximate to the bottom portion of the boat; a spray gun system; and a water intake system, comprising: a first water inlet tube having a proximal end connectable to a pump of the spray gun system and a distal end connectable to a swivel; a second water inlet tube having a proximal end and a distal end, the proximal end connectable to the swivel; a port connector connectable to the distal end of the second water inlet tube, the port connector having external threads threadingly engaging the port of the boat; and a water inlet conduit having a proximal end engageable with the port connector and a distal end positioned under the bottom portion of the boat.

The present disclosure relates to a guiding arrangement for a retractable thruster assembly. The guiding arrangement may comprise a foundation plate, a first upper guide, a second upper guide, a first lower guide, and a second lower guide. The first lower guide and the second upper guide may be arranged such that an arc angle within the range from 25 to 75 is confined therebetween. Thus, flexibility regarding the implementation of the retractable thruster assembly as L-drive or Z-drive may be gained.

An apparatus includes a buoyant frame that surrounds a space, and a net mounted to the buoyant frame such that the net extends across the space. The frame includes a plurality of linear segments, each including a respective structural member, foam, and a shell that covers the structural member and the foam. The apparatus may be placed on the surface of water adjacent to a boat to catch tools, replacement parts, etc. that may be dropped during boat repair or maintenance, thereby saving expensive tools and parts from being lost or damaged.

A cycloidal marine propulsion unit, including a hollow rotary casing having a central axis and defining a central inner space with an opening at an axial end thereof. A mounting body rotatably supports the rotary casing on a hull of a marine vessel. A rotating arrangement is provided for rotating said hollow rotary casing, while a plurality of blades extend axially from the rotary casing away from the hull. Each blade is mounted for pivotal movement with respect to the rotary casing, about respective blade axes. The rotating arrangement is configured to rotate the rotary casing by a circumference thereof. A blade shaft portion of each blade is at least partly received within the central inner space so as to attach said blade to the rotary casing.

A method of handling a unit arranged in a watertight hoisting chamber opening into a hull of a vessel is provided. The unit is adapted to extend into the water below the vessel when installed at its mounted position. The unit is clamped in its mounted position by clamping means and releasing fixing means fix the unit into its mounted position while holding the unit clamped in position. The hoisting chamber is at least partly flooded, the clamping means are simultaneously released and the unit lifted from its mounted position by applying a lifting force to the unit by lifting devices, and the unit is hoisted away from the hoisting chamber.

A water intake system for a boat spray gun, including a system utilizing a port through a transom of a boat, the port positioned proximate to the bottom portion of the boat; a spray gun system; and a water intake system, comprising: a first water inlet tube having a proximal end connectable to a pump of the spray gun system and a distal end connectable to a swivel; a second water inlet tube having a proximal end and a distal end, the proximal end connectable to the swivel; a port connector connectable to the distal end of the second water inlet tube, the port connector having external threads threadingly engaging the port of the boat; and a water inlet conduit having a proximal end engageable with the port connector and a distal end positioned under the bottom portion of the boat.