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Sonar enters the third dimension

New style of 3-D sensors lets ships avoid hidden obstacles.

By Stephen HumphriesStaff Writer for The Christian Science Monitor / July 3, 2008

FarSounder's new sonar device allows for 3-D images of what's around a boat. Finally, captains can answer the basic question in navigation: “How deep is the water in front of me?”

Courtesy of FarSounder


Warwick, R.I.

An anonymous garage in an industrial sector of Warwick isn’t the most obvious place to test a revolutionary piece of sonar technology. Yet the inside of this storage facility has been turned into a makeshift laboratory by two scientists who spend more time in face masks and wet suits than the traditional goggles and white coats.

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Fresh from a morning dive to retrieve a starfish-encrusted hydrophone (underwater microphone) from a nearby pier, Matthew Zimmerman and Matthew Coolidge turn their attention to testing a similar unit suspended on a pulley above the lab’s showpiece: a 22,000-gallon tank shaped like a rooftop water tower.

Once lowered into the custom-built vessel, the hydrophone barely creates a ripple. But in the maritime world, FarSounder’s sonar stands to make a big splash. It’s the first product to answer one of the basic questions in navigation: “How deep is the water in front of me?”

Today’s standard sonar, a depthsounder, only communicates the distance to the sea-floor directly beneath a ship. (As someone at FarSounder puts it, it’s like steering a car by only peering through a hole in the floor.) Less commonly used is Forward-Looking Sonar (FLS), a two-dimensional system for small boats that signals the range and bearing of a coming obstacle. But though FLS can detect an object, it won’t describe exactly where it is, nor its dimensions and depth.

By contrast, FarSounder’s new sonar combines all three dimensions – range, bearing, and depth – in a real-time view of the whole volume of water ahead of the ship.

By creating 3-D images of flotsam and jetsam floating in or under the water, it’s ideal for reducing collisions with the thousands of partially submerged containers that fall off cargo ships each year and, more important, avoiding whales.

It’s a perfect tool for navigation through shallow ports and narrow straits. Now, the “ping jockey” on a ship need never play a game of blind-man’s bluff again.

“It gives you a true underwater picture in real time,” marvels Branson Bean, a maritime consultant and writer about technical subjects related to supersized yachts.
Such a product might have come in handy for The Empress of the North, a cruise ship that ran aground off Alaska last year. It might also have warned the Queen Elizabeth II about the uncharted shoal off New England that scuppered its keel in 1992. And it may have saved the M/S Explorer, a cruise ship that guaranteed the journey of a lifetime, from sinking in November after it struck ice off Antarctica, briefly staining a pristine icescape with its red belly before it slipped from view.

In each instance, no lives were lost. But just one calamitous incident could wreck the entire cruise industry, says Craig Eason, technical editor of Lloyd’s List, a daily maritime news publication.

For that reason, cruise ships boast some of the most sophisticated bridge equipment available, he says. No surprise, then, that vacation vessels are a primary market for FarSounder. To date, four cruise ships have been retrofitted with the sonar system, including vessels that regularly voyage to territories such as ice fields.

The company also has commissions from luxury yachts, passenger ferries operated by the San Francisco Bay Area Water Transit Authority, and The World, the first luxury condominium cruise ship. The US Department of Homeland Security has even tapped FarSounder to adapt the technology to detect enemy divers in ports.

It’s a booming start for the 12-employee firm. And, for the most part, FarSounder expects smooth sailing ahead. But it could run into a few jagged reefs as it seeks to expand its market.