New modular control block for winches

Rexroth’s latest control blocks for high-pressure hydraulic marine winches are entirely assembled from standard components, the employing of proven techniques and technologies guaranteeing reliability. All components are carefully documented, and parameters such as tightening torques are measured, evaluated and documented to keep the possibility of component failure to a minimum.

The modular design of the HICWB is unique and means it can be combined with virtually any winch. The vessel’s owner can therefore hold fewer spare control blocks, providing greater options when dealing with changes. These new Rexroth blocks can also be combined with both axial and radial piston motors, and with their light weight of just 44 kg can even be directly motor mounted.

Each complete control block undergoes a specific treatment for maximum resistance to extreme offshore conditions. The blocks themselves are galvanized and chrome plated, and stainless steel is used for external moving parts such as the control lever and bushes. All adjustment elements have weatherproof covers. As a final protective barrier, a triple coating is applied in layers of 80 micron thickness.

Besides the required standard functions like counter balance, relief and anti-cavitation valves, these lightweight and compact control blocks offer a range of additional features. They can proportionally control the winches or capstans used to raise or lower the anchor. The so-called anchor break off function of the block, in combination with a variable displacement motor, enables the anchor to be broken free in a controlled manner. A three position hand lever valve is used for this function.

A second important feature of the control block lies in the ability to maintain a constant tension on the mooring lines when the vessel is berthed. When the mooring lines slacken due to vertical movement of the vessel, e.g. during tide, wave motion or loading/unloading, the winches will wind in to maintain line tension.