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.

Methods of protecting a propeller include applying an inner polymer layer onto a propeller. The inner polymer layer is impregnated with a biologically active chemical substance that inhibits biofouling-induced chemical, biological, and bio-proliferative damage and that does not chemically or galvanically interact with a material of the propeller. An outer polymer layer is applied onto the inner polymer layer, the outer polymer layer being impregnated with a biologically active chemical substance that inhibits biofouling-induced chemical, biological, and bio-proliferative damage and that repels biofouling organisms to prevent invasion of the inner polymer layer.

A micro-nano hierarchical structure for drag reduction and microbial adhesion prevention includes a metallic support plate having formed on its surface a plurality of arrays which are each composed of a plurality of metallic micro-structures and which are arranged in parallel, and a plurality of metallic nano-structures uniformly formed on the micro-structures and the support plate.

A micro-nano hierarchical structure for drag reduction and microbial adhesion prevention includes a metallic support plate having formed on its surface a plurality of arrays which are each composed of a plurality of metallic micro-structures and which are arranged in parallel, and a plurality of metallic nano-structures uniformly formed on the micro-structures and the support plate.

An ultrasonic system for treating a submerged surface of a target structure, the system including: an ultrasonic generator for generating electrical energy to drive first and second ultrasonic transducers, the electrical energy including at least two different frequencies including a first and second operation frequency; first ultrasonic transducers configured to be mounted as a first array to the target structure, and connectable to the ultrasonic generator and operable to generate a first ultrasound signal from the first operation frequency; and second ultrasonic transducers configured to be mounted as a second array to the target structure, and connectable to the ultrasonic generator and operable to generate a second ultrasound signal from the second operation frequency, wherein the first and second ultrasonic transducers are spaceable from one another to produce guided ultrasonic waveforms through the target structure including heterodyned frequencies from the first ultrasound signal and the second ultrasound signal.

An ultrasonic system for treating a submerged surface of a target structure, the system including: an ultrasonic generator for generating electrical energy to drive first and second ultrasonic transducers, the electrical energy including at least two different frequencies including a first and second operation frequency; first ultrasonic transducers configured to be mounted as a first array to the target structure, and connectable to the ultrasonic generator and operable to generate a first ultrasound signal from the first operation frequency; and second ultrasonic transducers configured to be mounted as a second array to the target structure, and connectable to the ultrasonic generator and operable to generate a second ultrasound signal from the second operation frequency, wherein the first and second ultrasonic transducers are spaceable from one another to produce guided ultrasonic waveforms through the target structure including heterodyned frequencies from the first ultrasound signal and the second ultrasound signal.

The invention relates to a hull of a vessel having characteristic surface properties, allowing an increase in surface runoff while benefiting from an inherent anti-fouling property and an original aesthetic appearance. Furthermore, the invention allows the incorporation of said outer composite envelope into the structure of the hull, thereby preventing delamination problems and inherently providing a vessel hull with the above-mentioned properties.

The invention relates to a hull of a vessel having characteristic surface properties, allowing an increase in surface runoff while benefiting from an inherent anti-fouling property and an original aesthetic appearance. Furthermore, the invention allows the incorporation of said outer composite envelope into the structure of the hull, thereby preventing delamination problems and inherently providing a vessel hull with the above-mentioned properties.

The invention provides an anti-biofouling system (200) comprising an UV-emitting element (210), wherein the UV-emitting element (210) comprises a UV radiation exit window (230), wherein the UV-emitting element (210) at least partly encloses a light source (220) configured to provide UV radiation (221), wherein the UV radiation exit window (230) is configured to transmit at least part of the UV radiation (221) of the light source (220), wherein the UV radiation exit window (230) comprises an upstream window side (231) and a downstream window side (232), wherein the UV-emitting element (210) also at least partly encloses an optical sensor (310) configured to sense radiation (421) emanating from the downstream window side (232) and configured to provide a corresponding optical sensor signal, wherein the anti-biofouling system (200) is further configured to provide said UV radiation (221) in dependence of said optical sensor signal.

The invention provides an anti-biofouling system (200) comprising an UV-emitting element (210), wherein the UV-emitting element (210) comprises a UV radiation exit window (230), wherein the UV-emitting element (210) at least partly encloses a light source (220) configured to provide UV radiation (221), wherein the UV radiation exit window (230) is configured to transmit at least part of the UV radiation (221) of the light source (220), wherein the UV radiation exit window (230) comprises an upstream window side (231) and a downstream window side (232), wherein the UV-emitting element (210) also at least partly encloses an optical sensor (310) configured to sense radiation (421) emanating from the downstream window side (232) and configured to provide a corresponding optical sensor signal, wherein the anti-biofouling system (200) is further configured to provide said UV radiation (221) in dependence of said optical sensor signal.