Hard to see and hard to track electronically, naval vessels have long posed special perils to nighttime navigation.
HONG KONG — The tropical sky off Singapore was dark when an oil tanker plowed into the side of the U.S. destroyer USS John S. McCain early Monday, but the moonless night may have been only one of the reasons the tanker’s crew had trouble seeing the warship.
Hard to see and hard to track electronically, naval vessels have long posed special perils to nighttime navigation. That has proved deadly this summer in crowded waters like those near Singapore and Tokyo, where another U.S. warship, the USS Fitzgerald, was struck by a cargo freighter under a waning crescent moon June 17. Seven sailors died.
The issue has prompted growing alarm in the commercial-shipping industry and in the U.S. Navy, which began pausing its worldwide operations last week to allow time for safety reviews.
“There have been four this year for the U.S. Navy, and the Singapore navy has experienced one or two” collisions with commercial ships, said Capt. Raymond Ambrose, president of the Singapore Nautical Institute. “We need an attitude of defensive driving out at sea.”
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Naval ships, designed to avoid detection by enemy fleets and aircraft, are exempt from an international requirement that vessels automatically and continuously broadcast their position, course and speed. They tend to have fewer lights than many commercial vessels, making them harder to see. They are painted gray to blend into the sea during wartime, and become even more difficult to spot at night. More modern naval vessels, including the John S. McCain, are designed to scatter incoming radar signals so that they are less detectable.
The Maritime and Port Authority of Singapore told The Straits Times, a Singapore newspaper, last week that the government’s vessel traffic-information system had not even known the John S. McCain was there until the tanker, the Alnic MC, carrying 12,000 metric tons of fuel oil, delivered a crushing blow to the warship’s left side. Two sailors from the ship, a guided-missile destroyer, are dead, and eight more are listed as missing and feared dead, as divers have begun discovering human remains inside the vessel’s mangled decks.
The Singaporean agency told The Straits Times that it had not detected the destroyer on radar and that its traffic-information system had not picked up data on the ship. In addition to radar, traffic-information systems rely on data from the Automatic Identification Systems that all but the smallest commercial vessels are required to use to broadcast information about their whereabouts.
Military vessels typically carry the systems but often turn them off because the captains do not want to reveal so much information. The Maritime and Port Authority had no immediate comment or elaboration on its statement to The Straits Times. A U.S. Navy spokesman declined to comment on what systems were operating aboard the John S. McCain at the time of the crash.
The difficulties with detecting naval vessels are amplified in busy waters, and those around Singapore are among the most crowded in the world because the city-state lies at the entrance to the Strait of Malacca, through which nearly all of East Asia’s oil imports and a large share of its seaborne exports move.
The congestion prompts military and commercial crews to turn off the early warning systems that alert them to potential collisions, said Capt. Harry Bolton, director of marine programs at California State University Maritime Academy and a merchant marine officer who has traversed the waters near Singapore dozens of times.
Modern ship radar automatically calculates the closest point at which other vessels will approach. The ship’s officers program the radar with a certain radius — typically 1 or 2 miles — and if any other vessel passes inside that radius, a beep begins sounding on the bridge.
The beeping can be switched off only when someone on the bridge hits a button to do so, acknowledging the warning has been received. But bridge crews commonly turn off the systems near Singapore because other vessels are frequently less than 1 mile away, so the beeping would be almost continuous.
“You turn them off,” Bolton said. “I can see everything, and I can look on radar.”
But ships like the John S. McCain, a Burke-class destroyer, are considered among the Navy’s best examples of vessels with a smaller radar signature, according to several former officers. They are low to the waterline, with equipment masts tilted to the ship’s stern, rounded edges and no large “citadels” rising high off the deck, like those on cruisers.
While commercial vessels traversing the Strait of Malacca illuminate their hulls and the waters immediately around them so they can spot any pirates who may be trying to climb aboard, heavily armed naval vessels with large crews have little to fear and are less lit up. Sometimes they appear like shadows moving among immense freighters resembling bright Christmas trees.
To better negotiate the Strait of Malacca, commercial-ship captains sometimes dispatch two crew members to the bow with radios to tell bridge officers about hazards ahead, said Tim Huxley, chairman of Mandarin Shipping, a Hong Kong shipping line.
A U.N.-affiliated organization, the International Maritime Organization, regulates international shipping. More than 170 countries are members, and the group has been cautious about imposing requirements that shipowners in developing countries might struggle to meet. But efforts are under way to develop such systems as part of an industry effort to develop autonomous ships.
Many commercial shipping experts say that the difficulty of seeing Navy ships is just part of the picture. They suggest the John S. McCain, with its powerful engines, advanced electronics and nimbleness, should never have moved into the tanker’s path, and they have been asking whether steering difficulties or poor bridge communications aboard the destroyer may have been factors. The Navy has said the ship’s steering system showed no signs of failure, though it has cautioned that the cause of the crash is still under investigation.
Aboard the John S. McCain, “You’ve got power and maneuverability; if you want to get out of the way, you can do it pretty quickly,” said Arthur Bowring, who retired in November after 20 years as managing director of the Hong Kong Shipowners Association.