A device for reducing underwater sound has a holding device and a hydrosound damper with noise reducing elements. The device has a transport housing for transporting the hydrosound damper, a first end of the underwater sound damper being fixed to the transport housing and the transport housing being connected to a holding device via a support device has a cable winch with a support cable arranged on the transport housing and has a motor-driven drum, wherein using the support device, the transport housing is lowered from the holding device to the sea floor.

A hydraulic noise suppressor for reducing water-borne noise, and method for handling the same, especially in the area of a construction site when an object is driven into underwater soil. The hydraulic noise suppressor can have at least two rigid holding elements, at least one support structure, and noise reducing elements secured to the at least one support structure, an upper end of the at least one support structure being secured to at least one of the at least two holding elements. The hydraulic noise suppressor can be divided along lateral flanks extending between the upper end and an opposite lower end of the at least one support structure.

A frame for guiding and supporting a foundation element, such as a pile, during installation in an underwater ground formation comprises a plurality of guide mechanisms that are movable between an extended position to engage a pile located inside the frame and a retracted position. At least one of the guide mechanisms comprises a slider, a path supporting the slider, a rotatable link, and an actuator to move the slider along the 10 path and the link between said extended and retracted positions.

A template for use in installing a plurality of foundation elements, in particular anchor piles, relative to one another in an underwater ground formation is provided. The template includes a plurality of guides for the foundation elements, which guides are fixed relative to one another by means of a frame. At least one of the guides includes a sound-insulating sleeve for surrounding a foundation element during driving.

A non-contact strain and/or displacement measurement system for use with structural objects having an optical device, a data store and an image arrangement that is fixed relative to the structural object to be tested, the optical device including an image receiving device for receiving visual images and the data store being configured to record the received visual images, the image receiving device being spaced from the image arrangement by an optical spacing such that the image receiving device has a visual range that includes a portion of the structural object and the image arrangement being within the portion, the image arrangement having at least one image element wherein movement of the at least one image element during a measurement period provides image data to calculate structural object strain and/or structural object displacement.

A pile-driver assembly for driving a pile into the ground, preferably offshore, and a method of driving a pile into the ground using the pile-driver assembly is disclosed. The assembly includes a casing defining a chamber, the chamber being configured to house a fluid. The assembly further includes a positioning element configured to position the casing at or on the pile, wherein at least a portion of the positioning element is positioned between the chamber and the pile. The assembly further includes actuating means, wherein actuation of the actuating means displaces the chamber relative to the positioning element, such that the chamber moves away from the pile, and wherein the actuating means is configured to release the chamber for displacement towards the pile such that a force is exerted by the chamber on the positioning member, to controllably drive the pile into the ground.

A device is provided for damping hydrosound in liquid emitted from a sound-emitting body in the liquid. The device includes a plurality of envelope bodies distributed in the liquid in an area of the hydrosound-emitting body and at a distance from each other. A material, diameter and pressure of each envelope body is configured such that a natural frequency of the envelope body corresponds to an emitted frequency range of the hydrosound so as to dampen the hydrosound. The device also includes at least one mass body disposed in the liquid. The envelope bodies are connected to the mass bodies so as to prevent the envelope bodies from rising up in the liquid.

A silencer for silencing the driving of piles into the bed of a body of water is configured to fit around a pile, and has a first tube; a second tube inserted inside and spaced apart from the first tube, both the first and second tube being longer than the depth of the bed of the body of water on which they are to rest; and a bottom wall, which is joined hermetically to respective ends of the first and second tube to form a gap between the first and second tube, and is configured to rest on the bed of the body of water.

There is disclosed an acoustic barrier (40) for use in a pile driving method in which a pile (I0) is driven into the ground 60, the acoustic barrier (40) comprising: an acoustic dampening layer (42); and a magnetic element (36); wherein the acoustic barrier (40) is arranged to be at least partly wrapped around an axial portion of the pile (I0) so that the acoustic dampening layer (42) at least partly surrounds the axial portion of the pile (I0), and wherein the magnetic element (36) is arranged to releasably secure the acoustic barrier (40) to the pile (I0). There is also disclosed a pile driving method comprising wrapping the acoustic barrier (40) around an axial portion of a pile (I0), driving an axial length of the pile (I0) into the ground, and removing or repositioning the acoustic barrier (40). There is also disclosed an acoustic barrier for a pile driving hammer having a support frame which can be detachable attached to the hammer.

A method of and a noise mitigation system for installing a foundation element, in particular a (mono)pile, includes a screen to be placed about a foundation element, in particular a (mono)pile, during driving of the foundation element in an underwater ground formation, to reduce noise input resulting from the driving into the surrounding water, e.g. a river or sea. The method and system comprise a further screen to be deployed about the (first) screen.