The Hand Controller used by the ROV pilot to 'fly' the ROV as he views the video monitor and other sensor information displayed on the video overlay, is connected to the Surface Control Unit by a 5 metre lead. All of the vehicle's control functions are incorporated in the Hand Control Unit. These include camera pan and/or tilt, autopilot functions, thruster trim controls, speed, direction, dive, surface and lighting intensity. Spare capacity for additional control functions is included.
An Umbilical connects between the Surface Control Unit and the ROV. For free swimming applications a tough, flexible, polyurethane sheathed umbilical is used. The umbilical contains power conductors to the ROV as well as control signal and video conductors. Spare conductors are provided for accessories such as sonar, survey sensors, CP probes and tools.
Launch and Recovery. The umbilical cable is designed to lift the ROV during the launch or recovery stages. It can be stored on a winch fitted with a slip ring for this purpose. However some operators save the cost of a dedicated winch and use a warping drum to take the weight of the vehicle during this process. The umbilical is coiled in a figure of eight to avoid any kinking and is then led to the warping drum from which it passes over an umbilical sheave to the ROV. When the ROV has been launched and sufficient umbilical has been deployed, the umbilical can be 'stopped' by taking a reverse turn on the warping drum.
The Umbilical Sheave can be fitted to a conveniently located ship's crane, davit or 'A' frame. In order to avoid damage to the umbilical, the sheave wheel must have a greater radius than the minimum bend radius of the umbilical.
No comments:
Post a Comment