Navy Is Constantly Hunting for Intruding Submarines : Sweden Engaged in Sensitive Game of Hide and Seek at Sea

ABOARD THE HMS STOCKHOLM —  Swedish navy ships are constantly on the prowl for alien submarines in the Baltic Sea, but the intruders just as constantly elude them in a maze of islands and underwater mountains.

“It’s like fox hunting,” said Cmdr. Lennart Danielsson, skipper of this flagship for Sweden’s anti-submarine warfare unit. “You have to stretch him, to be after him all the time, so that at last he’s so tired that he makes a mistake,”

So far the fox has escaped, but the hunters say they are getting closer.

The navy believes that during a three-week chase in June, a prowler may have been wounded by a barrage of depth charges and anti-submarine grenades, but the vessel slipped away.

‘I Think We Will Get Him’

“We almost managed this spring,” said Danielsson on the bridge of the HMS Stockholm during a training exercise. “I think we will get him in a couple of years.”

The Stockholm, with a crew of 29 men and three women, spends two weeks a month at sea, patrolling and following up some of the hundreds of reports from citizens claiming to have seen a periscope or a diving sub. Sometimes the invader turns out to be a frisky seal or swimming moose.

The anti-submarine unit can muster two corvettes, 12 submarines, seven minelayers, 16 patrol boats and 12 helicopters--all equipped with the latest sonar.

“One or two ships is not enough against a submarine,” Danielsson said. The tactic is to box in the intruder with sonar signals from all directions, then close in and open fire.

Never Has Snared an Intruder

Because it has never snared an intruder, the unit has had a credibility problem. Foreign experts have suggested that the Swedes may prefer to let the intruders go to avoid a diplomatic fuss. Danielsson said that isn’t true.

Sweden, which has not fought a war since 1814, dismissed the submarine threat until 1981, when a Soviet sub ran aground near the naval complex at Karlskrona. The incident jarred Swedes into understanding that their neutrality was no defense against foreign military adventures.

Experts who investigated a 1982 engagement also concluded that the other intruders were Soviet submarines as well, and Sweden lodged a diplomatic protest with Moscow. The inquiry also disclosed the existence of previously unknown minisubs launched from conventional submarines equipped with caterpillar tracks to crawl on the seabed.

Re-examining previous incidents, the Swedes concluded that the Soviets had been violating Swedish waters since the early 1960s.

Although the navy claims many confirmed sightings of alien subs, the Swedish government has not made any formal accusation against any nation.

The most recent engagement began Aug. 27 off the west coast north of Goteborg, but the chase was abandoned after two weeks.

The government has said it lacks the evidence to substantiate a charge against any specific country for that incident. The Soviets deny that their ships are involved and have suggested that the incursions are imagined.

Navy analysts believe that in wartime, the Soviet Union would want to neutralize Swedish defenses to allow its ground and air forces to transit Scandinavia.

The Baltic is one of only three sea outlets on the Soviets’ western front. The others are the frigid Barents Sea north of Sweden and Norway, and through Turkey’s narrow Bosporus strait into the Mediterranean.

To Danielsson, a 41-year-old career officer, it doesn’t matter whether the prowlers are from the West or the Soviet Bloc. His job is to stop them.

Danielsson said the intruders usually come in groups of six: two conventional subs and four mini-subs that can slip into the inner archipelago of about 24,000 islands. Often, they operate in several squads at the same time along the coast to tax Sweden’s defense resources.

Their mission is “pure intelligence, to learn everything there is to know about our coastal defenses,” Danielsson said.

Armed With Artillery

Danielsson’s 330-ton corvette is armed with artillery and depth charges that could sink a sub, but much of its weaponry is intended to punch holes in the hull of a sub and force it to the surface, rather than destroy it.

The ship bristles with the latest electronics. Its operations room is crammed with radar, sonar and television screens like a darkened arcade of Space Age video games.

But submarines have the advantage of the undersea terrain.

A craggy, mountainous seabed provides camouflage along a coast that stretches 4,750 miles.

Blizzard of Sonar Beeps

A strange mixture of varying water temperatures and salinity work to deflect the hunters’ sonar, and a junkyard of wrecks and metallic rocks bounce back a confusing blizzard of sonar beeps.

“We have learned a lot since 1982, and the first thing we learned was that it is much harder than we thought to catch a sub,” said Danielsson.

“He can go down to the bottom and pretend to be a rock, or he can move away very fast,” Danielsson said, and the normal chances of finding him are “less than 1%.”

The incursions are so politically sensitive that the commander said he would not be surprised if the intruders blew themselves up rather than surrender.

“These are pros, not amateurs. We will never see a submarine coming up and waving a white flag,” he said.