Page 12: of Marine News Magazine (July 2011)

12MNJuly 2011TECH FILEWeir-Jones Engineering Consultants Ltd., a Canadian company based in Vancouver, BC, has developed the Automated Draft Indicator System (ADIS). When installed on displacement hulls, high-speed and naval ves- sels and marine structures such as oil rigs, the ADIS enables operators to:?Record precisely how much cargo has been loaded or unloaded on vessels to avoid overloading or instability ?Control trim to reduce fuel consumption and improve handling of vessels ?Keep accurate loading records to satisfy regulatory or Coast Guard requirements ?Monitor the structural integrity of offshore structures Developed in conjunction with the British Columbia Ferries Services Inc., the ADIS system for vessels defines the position of the static water plane relative to the vessel. In this way the position of any part of the ship relative to the water plane can be accurately established. draft, free- board, heel and trim are easily measured, remotely and in real-time. ADIS defines the position of the water plane of the vessel relative to the position of the hull by accurately measuring the distance from four known positions on the hull to the mean position of the water surface. Multiple measurements are being made continuously, which aver- age out ripples, waves and the wake of passing vessels. The ultimate accuracy of the system as it is usually deployed is better than ± 3mm of draft or about one eighth of an inch.A typical installation consists of four ADIS ultrasonictransceivers mounted on a vessels hull fore and aft, port and starboard. They are directed at the water surface, and Weir-Jones Automated Draft Indicator System