ADIS - An evolution in marine safety...by Andrew Weir-Jones, The Weir-Jones Group

By BCShippingNews
May 14 2014
The Automated Draft Indicator System from Weir-Jones Group
The Automated Draft Indicator System - more accurate, more convenient; less intrusive, less maintenance...

Do you recall a time when the only way to measure the draft of a vessel was to stare at the draft marks on a cold and windy night, or to go alongside in a dingy in choppy water? Now there is a much more accurate and convenient alternative.

Reliable and repeatable draft data can be displayed on the bridge irrespective of the conditions at the berth or in the anchorage. ADIS™, the Automated Draft Indicator System, is not only much more accurate and convenient than the traditional use of draft marks, but it is far less intrusive and requires much less maintenance than pressure-based systems located inside the hull below the waterline.

ADIS™ calculates the draft and freeboard based upon the distance from the transceivers to the mean water surface. Unlike pressure-based systems, there is no need to correct for water density and temperature. ADIS™ provides a direct reading of the water plane position relative to fixed points on the hull — fore and aft, port and starboard, and amidships if there are concerns about hogging or sagging. And all without any hull penetrations above or below the waterline.

The through-hull penetrations below the waterline required for pressure-based draft monitoring systems can be managed and maintained, albeit with a degree of difficulty and cost. However, a “dry” option exists, and most mariners lean towards ‘no through hull penetrations’. In addition, sea creatures make the pressure ports home, compromising the functionality of the transducers, rendering the pressure-based system’s reliability ‘questionable’, and necessitating maintenance in dry dock.

ADIS™ was developed with the assistance of the British Columbia Ferry Corporation in 1995. Since then, it has provided hundreds of millions of real-time draft measurements on the West Coast. It has become the ‘go-to piece of equipment’ for operators and regulatory agencies in Alaska, British Columbia and Washington State when there is a need to confirm that passenger vessels are operating safely and within design parameters.

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