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Farsounder's forward-looking sonar system has a lot to commend it, whether for collision avoidance or underwater-intruder detection. Consider this incredibly useful tool as a beneath-the-surface 3D radar! June 2008

JUNE 2008

FarSounder’s forward-looking sonar system has a great deal to offer the big-yacht sector. Its 3D images of what lies directly ahead of a vessel can not only help avert potentially disastrous collisions with underwater objects - whether uncharted reefs and rocks, partially submerged containers or, say, the odd basking whale – but also they can make a valuable contribution to onboard security systems – providing warnings, for instance, of any unwelcome underwater visitors.
Such a forward-look capability should prove particularly useful for those more adventurous cruising schedules that take in waters where charting surveys are poor at best – the sort of locations, in theory at least, where you would expect to see expedition and explorer-style yachts.
Make no mistake. There is nothing quite like the FarSounder system available elsewhere. This is not some glorified fishfinder. It is robust big-yacht, big-ship equipment – and you’ll be surprised to hear it does not have its origins in the military sector. Initial development of the system was led by a professor of ocean engineering at URI (University of Rhode Island), although since then the US Navy, US Coast Guard and US Department of Homeland Security have all shown predictable interest in the technology for host of applications.

'What makes FarSounder system so good is the fact that it delivers its information in real time and its range is good enough so that should there be a navigational problem ahead there will be time for the necessary course corrections to be made...' 

Yachts with the FarSounder system installed thus far include new-builds such as the 68m Lürssen Kismet and the Devonport 77m Samar; plus retrofits like the 160m royal yacht Dubai and the three-year-old 66m Oceanco Dilbar, says Ian Bowler, one of FarSounder’s vice-presidents.
Plus at least four large cruise ships also have retrofitted FarSounder too – the likes of Clipper Adventure, Clipper Odyssey, Spirit of Oceania and The World.
One of the most recent new-build yachts to launch with the system already installed aboard is the 54m CRN Maraya and probably the smallest yacht to take an installation thus far is the 37m Trinity-built Mary P.
Then there is a host of work-in-progress motoryacht projects that will incorporate the FarSounder system too – 75.5m Project 703 (Oceanco) and the 130m Project May (Kusch) are just two that can be mentioned and there are several others that can’t; and HJB’s 62m Athos will be the first sailing yacht to receive an installation.
What makes FarSounder system so good is the fact that it delivers its information in real time and its range is good enough so that should there be a navigational problem ahead there will be time for the necessary course corrections to be made. It has a range of up to 330m with its ‘field of view’ set at 90 degrees, but up to 440m with a more restricted 60-degree picture.
As to how clear it can be for the user, Paul Weir, one of the two captains aboard the CRN-built Maraya, puts it in a nutshell. “Our FarSounder, which on his boat can be viewed on one of five Kelvin Hughes bridge monitors, is so good I have literally watched the anchor trip from the seabed and winched up to towards the yacht’s bulbous bow, which incidentally houses the transducer,” he says. “I don’t suppose you could expect much better definition.”
Such accuracy and sensitivity is why several big yachts make use of the system for underwater surveillance and threat-detection purposes. It would be relatively easy to sea a diver approaching, for instance.
FarSounder works by sending out multiple ‘pings’ from a sophisticated transducer - pings that effectively provide range and bearing information every second. What echoes come back are analysed by some clever Windows-based software to create a 3D view. The user can choose the viewing angle too, just like if viewing a 3D model on a CAD system or a computer game. You see what you want to see and if things aren’t clear enough one simply changes the perspective.
The transducer head is the heavy bit of the system. It weights in at around 36.4m (80lbs). Then there is a rack-mount ‘power-module’ box, which needs to be located somewhere within 30m (100ft0 of the transducer. The required power supply should be 100W continuous, ideally with a ‘quiet’ UPS (uninterrupted power supply), so no electrical noise pollution can get to the sonar signals.
The transducer for the system essentially consists of a circular black urethane-faced array that we understand comprises no fewer than 100 receivers, although actually only 96 work; the four corner arrays aren’t used.

'And thanks to real-time roll-and-pitch compensation, it can cope with plus or minus 20 degrees movements without compromising the on-screen delivery...'

The transducer unit itself is large, about 254mm (10in) in diameter, so, say, about the size of a dinner plate. Then there’s a 178mm (7in) diameter tube behind it and the faring collar is probably 305mm (12in) in diameter. Note the faring collar should not be installed with any silicon sealer as water needs to flow through some of the slots in the collar for cooling purposes. Incidentally the tubes and collar materials are usually 316 grade stainless steel, but if need be they can be supplied in other alloys in order to be a better galvanic match with hull materials.
When mounting, the array face should be mounted squarely so that it looks straight ahead. And thanks to real-time roll-and-pitch compensation, it can cope with plus or minus 20 degrees movements without compromising the on-screen delivery.
Installing the FarSounder FS-3 and FS-3DT units is claimed to be relatively easy. The transducer module should be located as far forward and as deep as possible in a vessel. The recommendation is that it should be located on a vessel’s centreline and at least 3ft (915mm) below the waterline and ideally in bubble-free water, often referred to as ‘clean’ water.
An obvious transducer location would be around a stem base. The centre of a bulbous bow is probably the ideal – as seen in several of the yacht applications. But they also can be located to the side of a stem in a tube – a solution that can help with particularly pointed bows - but only if the bow doesn’t obscure the transducer’s ‘field of view’.
Another good transducer location would be a sailing yacht keel; for instance, that’s where the one board Athos will go. And putting the transducer in a hydraulic retractable pod, possibly one that is also capable of rotating too, would be another alternative, particularly of interest, one would suspect, for those with more interest in the underwater security aspects of the technology.
To give an idea of likely costs, a FarSounder installation would typically require a total budget provision of US$100,000, of which around US$90,000 would be the necessary hardware, which consists of transducer head, power control box, cabling and so on.
Based in Warwick, Rhode Island, FarSounder came into being in 2000/01 and is being driven by owner and CEO Cheryl M Zimmerman.

For more, www.farsounder.com.

© Phil Draper