In an electric winch system, the wave movement is compensated by automatically driving the winch in the opposite direction at the same speed. The hook of the winch will thus keep its position relative to the seabed. AHC winches are used in ROV-systems and for lifting equipment that is to operate near or at the seabed.
What is heave compensated crane?
Passive heave compensation is a technique used to reduce the influence of waves upon lifting and drilling operations. A simple passive heave compensator (PHC) is a soft spring which utilizes spring isolation to reduce transmissibility to less than 1. PHC differs from AHC by not consuming external power.
What is heave accuracy?
Abstract. Accurate heave measurements are important in many applications to compensate for vessel wave motion, e.g. in hydrographic seabed mapping, dredging, and offshore crane heave compensation. The accuracy is often specified to be better than the larger of 5 cm and 5% relative.
How does a crown mounted compensator work?
By supporting the crown block with controlled tension the compensator becomes a motion nullification device by raising and lowering the crown block. This then raises and lowers the traveling block and hook to nullify motion or to isolate rig motion from the drill string.Jan 7, 2022
How does heave compensation work?
A passive heave compensation device acts as a spring devicespring deviceThey are also common in science education as basic accelerators. They are used when the accuracy afforded by other types of scales can be sacrificed for simplicity, cheapness, and robustness. A spring balance measures the weight of an object by opposing the force of gravity acting with the force of an extended spring.https://en.wikipedia.org › wiki › Spring_scaleSpring scale - Wikipedia with a predefined, relatively low stiffness. It allows relative motion while keeping load variations in wires, suspending the load within acceptable limits. Passive heave compensation systems normally require no power supply for their operation.
What is AHC technology?
The essential function of AHC technology is the ability to land and retrieve subsea installations to and from the seabed with precision and accuracy, while minimising the impact caused by the motion of the vessel.
What is manual overload protection system?
Manual Overload Protection System (MOPS) Protection system for the crane for loads higher than the design load. Manually actuated by the operator.
How is heave measured?
The heave measurement can be output in four different locations (the MRU itself, CG, MP1 and MP2) simultanously on the same serial line or Ethernet port. Typical monitoring point is the transducer head or the crane tip. The MRU 3 outputs roll, pitch and heave together with linear acceleration in 3-axes.