Captain's Table: Forward looking sonar in 3-D

At December's International WorkBoat Show, I had the opportunity to check out new sonar technology that provides navigation assistance for commercial vessels. It has the potential to provide the captains of high-speed passenger vessels advance warning to prevent contact with an unknown bottom obstruction.

FarSounder Inc. is marketing commercial 3-D, forward looking sonar that shows all three dimensions of a 90° field of view with each ping. This provides effective detection needed for avoiding obstacles by showing continuously updated range, bearing, and depth information on underwater objects forward of the vessel.

There are currently two models available that provide information up to maximum ranges of 1,000' or 1,400'.

The sonar transmitter and listening devices are encased in a bow-mounted transducer that is connected by cable to a power module about the size of a briefcase. The user interface runs SonaSoftTM, a Windows XP-based graphical program that can run on a laptop or marine computer.

The 3-D volumetric navigational display provides vessel location on electronic charts with a depth profile and a color-mapped scale. It can also display GPS, vessel speed, and heading data. The system can set up with alarms for obstacles or particular depths.

More descriptive and technical information is available at www.farsounder.com.

A third model now in the planning stages will have a range of 12,000'. Since I am currently helping in the development of a new fast-ferry service that will occasionally come in contact with nearby marine mammals, I am particularly interested in detecting them at the longest range possible. A 40-knot ferry would have three minutes to avoid a recognized obstacle that lies two miles ahead.

Slower-speed vessels will also find this aid useful, particularly when operating in shallow water, to locate uncharted hazards as well as objects marked on charts as present but not precisely located, such as wrecks and shoals.

Recently, New World Ship Management Co. announced that FarSounder sonar systems would be installed onboard its Clipper Cruise Line vessels Clipper Adventurer and Clipper Odyssey.