The Sea Less Travelled
From The Crew Report, Issue 80
With more superyachts cruising atypical waters, the dangers presented by insufficient chart data are increasing. Marianne Molchan, president of Molchan Marine Sciences, looks at the role of forward-looking sonar and how it could be a game changer for the adventurous owner-captain team.
To all those superyacht owners and captains yearning to cruise among calving glaciers and smiling belugas in ice-filled waters, take note. The number of commercial ships and passengers entering the Arctic and Antarctic in the past 15 years has, according to some figures, nearly quadrupled, and this trend in cruising Polar waters extends to superyachts.
The SeaXplorer, designed as the first purpose-built, Polar Code-compliant range of expedition yachts, was on display at the 2015 Monaco Yacht Show. As superyacht owners with adventurous travel aspirations push navigational safety limits in both Polar and remote tropical locations, the risks of grounding and damage to the vessels increase exponentially. Equipped with the appropriate technology, experience, safety equipment and a chaperone vessel, the risks to cruisers and their vessels drop significantly. The 2007 sinking of cruise ship M/S Explorer and the subsequent safe rescue of all passengers in the Antarctic shows just how important ship-chaperoning can be.
Shipping and Safety Review stated there were 55 ship accidents in the waters of the Arctic Circle in 2014, an increase from the three accidents reported in 2005. The biggest danger to vessels cruising these remote waters is damage caused by grounding or hitting an iceberg. Due to the lack of nearby rescue assets and the short human survival time in frigid waters, a hull breach can quickly turn into a catastrophe. In 2007, the 294-passenger ship Nordkapp ran aground near Deception Island in the Antarctic, tearing an 82ft-long gash in its outer hull. In 2011, the double-hulled cruise ship Polar Star breached the outer shell of its hull off Antarctica's Detaille Island. These were just two of 19 cruise vessels that reported groundings in Arctic, Antarctic, Norwegian and Alaskan waters between 2003 and 2013, according to reports.
“The US and Canadian Coastguard Agencies estimate that only 10 per cent of Arctic waterways are known in detail,” reads an Allianz Expert Risk article. Producing nautical charts is an expensive and time-consuming process, while Polar charts remain substandard in comparison with the density of soundings and frequency of chart updates in other regions of the world. Moreover, the sea less traveled is less likely to be covered by charts with ample soundings or frequent updates. Where there is substantial ice moving in the ocean there can be annual seabed scouring and movement of rocks, causing chart inaccuracies. One example is the port of Anchorage, Alaska – a commercial port, adjacent to Cook Inlet, which can be ice-filled in the winter and hosting pods of Beluga whales in the summer.
As a hydrographer for the National Oceanic and Atmospheric Administration (NOAA) charting Cook Inlet in the mid-1970s, and comparing daily surveys against the most recently published charts, it was very clear that the seabed was shifting due to bottom type, strong currents and ice scouring. What was most troubling was the fact that we charted substantial rocks in navigable waters that were in 'new' locations and just below the mean lower low water level. With a 30ft-plus tidal range, most vessels would have no trouble cruising over the 'new' rocks at high tide but would get into trouble at low time.
In 2017, designated vessel operators in Polar regions will be required to complete a Polar Waters Operational Manual, outlining measures for operating in waters with limited hydrographic, meteorological and navigation information. During the finalization of the Polar Code, maritime lawyer Michael Kingston, representing the international Union of Marine Insurance, suggested to the International Maritime Organization (IMO) that a Forward Looking Sonar (FLS) would lower risk by providing timely detection of uncharted, hazardous seabed features, as stated in SeaWays Magazine.
Not all FLSs have the same capabilities. There are inherent limitations to scanning 2D FLS technology; with this type of sonar, accuracy in shallow-water environments can be unreliable with negative effects upon the data quality due to the pitch and roll of the vessel. And, of course, delayed data display due to the scans can have negative consequences.
The biggest advantage of a FLS is to be able to anticipate - and get out of the way of - obstacles in time. A three-dimensional, single-ping FLS gives an instantaneous data display to the operator. An effective system must be capable of detecting obstacles with enough lead time for the operator to react accordingly. It should also provide depth information at a range of speeds.
One of the most respected 3D Sonar manufacturers is FarSounder. The system display is intuitive and fully refreshed with each ping. FarSounder sonar eliminates multipath interference such as a reflected signal from the ocean surface. This system's 3D colour-mapped image of the area forward of the ship combines three navigationally significant components: depth, range and bearing in real time.
The image included in this article shows FarSounder's chart overlay with sonar images of the seafloor and in-water targets. The upper right-hand side of the image, in yellow, reveals the heading of the vessel at 63.8 degrees, the speed at 4.3 knots and the GPS position of the vessel. Below is the swathe of coverage out to 500m showing the obstructions in the water. The left-hand side of the image is the chart overlay of the obstructions detected by the FLS.
The orange, yellow and red dots along the bulkhead show the in-water obstacles that are navigationally significant; they are not charted and may not be visible above water. The standard user interface software includes automated alarms, DPS compass, depth-sounder display and vector-based chart-plotting capabilities. It is no surprise that militaries worldwide have purchased FarSounder FLS to support multiple missions.
In 2016, the Royal Australian Navy (RAN) purchased four FarSounder-1000 systems plus spare parts for survey-vessel system upgrades. Why? Because the RAN has a long history in development of FLS; it recognizes the value of FarSounder's technology, sonar accuracy and intuitive display. This upgrade provides their hydrographers with the capability to safely enter and exit shallow, unpredictable survey areas. They operate in both in tropical and ice-filled waters in support of multiple missions. The fact that the RAN is installing the FLS on a fleet of four 360-ton survey vessels serves as an example to superyacht owners looking to upgrade or build a navigationally safe vessel.
In 2013, the NOAA made an uncharacteristic move and began using crowd-sourced hazard to navigation data from website ActiveCaptain for its internal 'cartographic toolkit in the charge evaluation system'. ActiveCaptain is an online, real-time maritime navigation tool providing vessel owners with marine data, reviews, local knowledge, anchorages,and hazard to navigation information which, according to its website, is being updated 1,000 times a day. The value of this information cannot be overstated. While travelling down the Intracoastal Waterway in our vessel with a 5ft draft in inlets near Charleston, South Carolina, we relied daily on the timely updates of ActiveCaptain contributors to determine what tide state we needed to pass safely through shoaling inlets. These inlets were correctly reported to be 4ft deep at mean lower low water level while the charted depth was 15ft. Today, both the US Coast Guard and NOAA use data pulled from reputable crowd sourcing such as ActiveCaptain (i.e. missing navigation aids or shoaling in inlets) to prioritise work for their aids to navigation and surveying assets.
FarSounder is currently working on software to incorporated FLS navigation data into a near real-time individual ship chart update. “The future FarSounder owner will be able to build their own 3D charts by storing and combining the sonar's real-time data of all the places they've been,” explains Matthew Zimmerman, vice president of engineering at FarSounder. “Before approaching that uncharted lagoon, barrier reef or secluded anchorage, the captain will be able to review their own survey from their last visit. With each transit, the wide horizontal coverage of the sonar will allow them to expand the coverage of their own personal survey while keeping the vessel safely within areas covered by their previous visits. Eventually, FarSounder data from multiple vessels could be shared with each other to build an even larger survey coverage.”
Hydrographers are the first to admit that charts don't tell the whole underwater story, especially in remote locations and locations with seasonal weather effects. Prudent navigators should use all senses and tools available. If the goal is to navigate the sea less travelled, having an accurate 3D image of the seafloor well ahead of the vessel is key to safe navigation. The first thing to hit a shoal should be the ping from a forward-looking sonar, not the bow of the vessel