The cables are placed by a cable laying vessel pulling an underwater plough that cuts a furrow and simultaneously places the cable in it, but the start point for the plough is crucial and must follow the pre-determined route where no other obstructions, cables or pipelines are present. As Martin Smith

from Gardline Environmental explained, 'Easytrak was used at the critical phase when the plough is deployed from the stern of the barge to a start position, which would otherwise be unknown.'

The system’s transducer was deployed on a pole from the vessel and the beacon was attached to the plough tilted at an angle for the best acoustic path. Easytrak fixed the start position in water depth of 16m for the main part of the operation, and was used again in shallow water in the secondary phase.

Serial connectors allow the integration of a GPS receiver, external motion sensors, gyrocompass and a data-out port for use with navigation packages. Also included are an Ethernet port, allowing a remote user PC to display the tracking data, plus a USB mouse port.

Technical development of the product continues, in particular to meet the challenge of high accuracy acoustic positioning along with greater flexibility in day to day operations. As an example of this, a new transponder, part of the small Micro series, has recently been designed with a rechargeable battery pack and external connector so that it can operate continuously from ROV power supplies, giving it extra versatility. With an increased source level and hemispherical beam pattern, the new 319 is default compatible with Easytrak, but can also recognise other tracking systems. Similarly, Eastyrak’s software is constantly being enhanced, with the latest feature soon to be available being remote display software. This hunts for Easytrak on a computer network and then allows the user to view the tracking and change any local viewing parameters, or set up local waypoints.