Hawser Load Monitoring Systems
Part No: HLW10
Hawser Load Monitoring System is used for monitoring the tension in Hawsers linking a sea vessel to a SPM.
Application: A system to measure and record the Hawser loads on an Imodco buoy. The measurements to be relayed to the tanker bridge by radio telemetry. The tanker equipment is portable which can be carried onboard as required.
The equipment needs to be simple to install, cost effective, and of short delivery time to overcome an immediate requirement.
Two load-measuring pins are fitted to the buoy's mooring shackles. Armoured cables relay the load signals to a small telemetry enclosure mounted on the rope cage above the buoy deck. An omni-directional antenna is mounted above the rope cage. Power for the telemetry is from an enclosed battery enclosure. If the fitting is intended to be permanent, then a marine solar panel can be added to maintain battery charge.
The telemetry unit for the tanker is in a rugged steel container, and comprises telemetry receiver, display and alarm electronics and, optionally, chart recorder. A directional antenna is supplied for external fitting to the vessel.
The Imodco design has two lugs for mooring shackles out-board of the mooring arm of the buoy's turntable. In a permanently fitted design these pins are replaced with instrumented pins, and are each rated for 150 tonnes safe working load, as are the original pins.
If the requirement is intended to be less permanent, then standard 150 tonne instrumented shackles can be supplied which connect between the buoy's shackles and the hawser's end fittings.
The pins are to an existing design for Imodco moorings, these are fully hermetically sealed and pressure tested to 50 metres water depth.
These are wire armoured flexible multicore cables with sub-sea connectors at the load pin end.
Buoy Telemetry Unit.
The unit is a stainless steel enclosure sealed to IP66 waterproof standards, and comprises twin signal amplifiers, safety barriers and telemetry module. The telemetry module digitally encrypts the load signals to the transmitter.
The transmission is based on European ETSI Standard EN 300 220-1 UHF approved transmissions for telemetry. Client to advise if local PTT regulations require a different standard or frequency to be used. Experience has shown that transmissions have a range of 10 kilometres in an offshore environment.
Hazardous Area Considerations.
The area around the centrewell and above the turntable deck to a height of 1 metre is usually regarded as a zone 2 hazardous area. The equipment is proposed to be above this area, however the instrument cables to the pins may pass through the zone and so electrical signals are fitted with suitable approved safety barriers.
Tanker Telementry Unit.
The unit is enclosed in a lightweight by rugged enclosure which can either be permanently installed or carried onboard at the time of berthing.
The unit displays current load on an LED display and previous maximum load. Audible and visual alarms can be set to trigger for a particular load level. Chart recorder provides a hard-copy of load levels during the berthing. The Unit can display two hawser loads for a twin hawser mooring, or optionally a combined total load.
The unit is mains powered.
The telemetry is included in this unit, with antenna cable and directional Yagi antenna. Antenna has clamps for attaching to external ship's structure.