A structure for reducing the drag of a ship and its application thereof is provided. The structure for reducing the drag of a ship includes at least one turbulence generating structure which is installed on the side surface between the widest section and the aft end or on the bottom surface between the deepest portion and the aft end of the ship. The arrangement of the turbulence generating structure can generate turbulence to reduce the drag of the ship, and thereby increase the speed of the ship and/or reduce the ship's fuel consumption.

The invention relates to a cover device for at least sectional closing of an underwater opening in a hull of a watercraft, in particular an opening of a transverse channel of a thruster. According to the invention the cover device includes at least one variable-volume hollow chamber lip including at least one buoyancy body, and the at least one hollow chamber lip is shiftable into an expansion state or into a shrinkage state by supplying or removing a fluid, in particular air. As a result of the variable-volume or inflatable cover device a more reliable and simultaneously lower-maintenance operation of the cover device is given. In addition, the invention has a thruster, in particular a bow or stern-thruster, as subject matter.

The invention relates to a cover device for at least sectional closing of an underwater opening in a hull of a watercraft, in particular an opening of a transverse channel of a thruster. According to the invention the cover device includes at least one variable-volume hollow chamber lip including at least one buoyancy body, and the at least one hollow chamber lip is shiftable into an expansion state or into a shrinkage state by supplying or removing a fluid, in particular air. As a result of the variable-volume or inflatable cover device a more reliable and simultaneously lower-maintenance operation of the cover device is given. In addition, the invention has a thruster, in particular a bow or stern-thruster, as subject matter.

A structural component for a vehicle has a surface with a riblet structure. The riblet structure includes a plurality of grooves, including a first groove having a first longitudinal section forming a first angle with a main longitudinal direction of the structural component. The first angle is larger than 0 and the main longitudinal direction corresponds to a flow direction of a fluid along the surface of the structural component.

A structural component for a vehicle has a surface with a riblet structure. The riblet structure includes a plurality of grooves, including a first groove having a first longitudinal section forming a first angle with a main longitudinal direction of the structural component. The first angle is larger than 0 and the main longitudinal direction corresponds to a flow direction of a fluid along the surface of the structural component.

In order to provide a rudder blade, which has a low level of weight, is easier and more inexpensive to manufacture, that meets the various strength and stability requirements for various rudder-blade sections, which can be at least partly manufactured in an automated manner and for which the manufacturing of irregular surfaces, in particular, the leading edge, is made easier, a rudder blade is proposed, which has a modular structure, wherein the rudder blade comprises at least two prefabricated rudder-blade segments and is composed of the at least two prefabricated rudder-blade segments.

The present invention relates to structured, gas-holding surfaces for improving the friction-reducing properties of gas layers held under a liquid and for the simultaneous suppression of turbulence. The present invention furthermore relates to a device comprising this structured, gas-holding surface and to the use of this structured, gas-holding surface.

A cavitation load-reduction device for an underwater vehicle has adjustable water-entry angles. It contains a cavitator disposed at a head end of an underwater vehicle, a front end of the cavitator being detachably connected to a head fairing device that is coaxially arranged with the cavitator. The head fairing device comprises a head fairing, a plurality of notches are arranged in a rear end of a side wall of the head fairing around an axis of the head fairing, fairing tiles hinged to the notches are arranged at the notches, and the fairing tiles are matched with the notches. Each fairing tile retractable arm is separately hinged to the fairing tile and the cavitator, and the fairing tile retractable arms are used to drive the fairing tiles to rotate around a hinge point of the fairing tiles and the head fairing.

A cavitation load-reduction device for an underwater vehicle has adjustable water-entry angles. It contains a cavitator disposed at a head end of an underwater vehicle, a front end of the cavitator being detachably connected to a head fairing device that is coaxially arranged with the cavitator. The head fairing device comprises a head fairing, a plurality of notches are arranged in a rear end of a side wall of the head fairing around an axis of the head fairing, fairing tiles hinged to the notches are arranged at the notches, and the fairing tiles are matched with the notches. Each fairing tile retractable arm is separately hinged to the fairing tile and the cavitator, and the fairing tile retractable arms are used to drive the fairing tiles to rotate around a hinge point of the fairing tiles and the head fairing.

Pontoon hulls, devices, systems and methods for providing lower friction surfaces on the hulls to increase the efficiency of motorized pontoon boats moving through the water. The inner side walls and the tunnel ceiling surface between the pontoons in a motorized pontoon boat can be provided with a plurality of longitudinal vent channels in a U shaped configuration. The vent channels can have open ends facing the rear end (stern) of the water craft and opposite closed ends facing the forward end (bow) of the water craft. As the water craft moves forward, a bubbling effect can occur in low pressure zones about the rear (stern) facing open ends of the plurality of vents to reduce the water surfaces in contact with the pontoon hull surfaces. A plurality of open rear (stern facing) ends of the vents and closed front (bow facing) ends of the vents can be arranged in series with two parallel vent series on a left inner sides of the left pontoon, two parallel vent series on a right inner sides of the right pontoon, and two parallel vent series on top of the tunnel between the pontoons.