In addition to being a major commercial port and shipyard, Wilhelmshaven was Germany’s largest naval base on the North Sea coast. While Germany’s small missile boats functioned well in the Baltic, the wilder, rougher weather of the North Sea demanded bigger, more capable ships. For that reason most of the German Navy’s frigates and destroyers were based there.
It also made the Germans very protective of this valuable port. Constant fighter and helicopter sweeps above the water were matched by patrolling submarines and minefields below the water.
Germany’s naval staff was confident of Wilhelmshaven’s defenses. A combination of interceptors, SAMs, and antiaircraft guns had already driven off one abortive American air raid against the base, inflicting what were reported as heavy losses on the enemy.
Now ships sheltering inside the protected port would be used to strengthen other areas along the coast. The minelayer Sachsenwald, escorted by two frigates and two minesweepers, had been ordered to lay a new barrier across the Elbe River mouth, near Cuxhaven and the western entrance to the strategically and economically vital Kiel Canal. The canal connected the Baltic with the North Sea. In addition, Germany’s second largest city and most important port, Hamburg, lay only seventy kilometers up the Elbe.
While the shoreline hinted at easy access to the river, the actual shipping channel was long and narrow. Silt filled the rest of the bay, forming shallows barely covered with water. That narrow entrance made it easy to “lock the front door” with a mine barrier.
With an entrance and exit route known only to Germany’s own harbor pilots, a defensive minefield would make any naval attack on Hamburg or the Kiel Canal, by stealth or strength, a risky undertaking.
Defensive minefields are an important, if low-profile, part of naval warfare. Mines, even sophisticated modern ones, are cheap, never sleep, and are very hard to remove. They have been used for over a hundred years. When Farragut damned the torpedoes and ordered full speed at Mobile Bay during the American Civil War, he was actually referring to Confederate-laid mines. Farragut’s Union ships had broken past those primitive mines and captured the port. Germany’s naval commanders doubted the American admiral’s successors would find it easy to duplicate his feat.
With the sun gleaming on their gray camouflaged superstructures, the five German warships sortied out of the Jadebusen, through the wide mouth of the bay. They were careful to stay not just in the buoyed channel, but in a special passage marked on their charts. Wilhelmshaven had its own large defensive minefield.
The minesweepers led the way. Using ultrahigh-frequency sonars, they swept the channel for enemy mines that might have been laid by submarines or aircraft during the past several days.
Sachsenwald followed, flanked on either side by guided missile frigates. With their sonars and radars energized, they would screen their charge from air, surface, or submarine attack. This was not a job for stealth or concealment. This close to home they could count on a lot of help if they came under attack.
Just to be on the safe side, an antisubmarine helicopter crisscrossed the formation’s path, dipping its sonar into the water for periodic searches. Even the fighter patrols orbiting high overhead followed racetrack patterns that kept them close to the group.
Proceeding at fifteen knots, the formation steamed northeast for four hours, crossing in front of the Weser River mouth and Bremerhaven on their way to the Elbe. The German warships actually had to go out a fair distance into the North Sea to clear the shallows, before they could make the turn back toward Cuxhaven.
Nothing menaced them during the short voyage. Once they rounded the western point of the river’s mouth, the covering force spread out while the minelayer went to work.
Sachsenwald was an old ship, but minelayers don’t need fancy sensors or weapons systems. She was fitted with the latest navigational gear, and her capacious holds carried almost a thousand SAI moored mines. Steering a slow, straight course, her sailors planned to spend the entire day rolling the deadly devices out ports in her stern. Each would be dropped as part of a carefully predetermined pattern, weaving a deadly and nearly impenetrable web.
When the conflict started, the British submarine Ursula had been in port. Acting under orders issued by the admiralty, her crew had worked rapidly to off-load some of her Tigerfish and Spearfish torpedoes and to replace them with a smaller but equally deadly cargo — Stonefish mines.
Ursula had sailed from its Scottish base that same night and arrived off the Elbe four days later — intact and undetected despite a few close brushes with EurCon ASW patrols. The same shallow seas that hampered British and American sub-hunting efforts cut both ways.
Creeping in on her whisper-quiet electric motor, the small submarine had maneuvered in close to the German coast, crowded by the shallows and bucking the currents at the river’s mouth. The same eddies that made it difficult to maneuver, though, helped hide her from enemy sonar. The mix of fresh and salt water where the Elbe met the North Sea further confused the sonar picture.
With her tubes loaded with mines instead of torpedoes, Ursula had moved along a preplanned track — firing them one after another during an hour-long, nerve-racking cruise down the main shipping channel. Then, its mission accomplished, the British submarine had crept out by the same way it had come, with no one the wiser.
One of those Stonefish mines now lay in Sachsenwald’s path.
Other German ships had already come near the mine as it lay half-buried in the mud on the channel floor, but each of them had been rejected as a potential target by the microchip in its brain. Most had been fishing craft or patrolling gunboats. A pressure sensor measured their wake as they passed, and spurned them as too small. Several vessels — mostly freighters and barges — were large enough, but the mine’s acoustic sensor rejected them because they didn’t match the sound signatures loaded in its memory.
One of the ships the Stonefish had ignored was a minesweeper towing a magnetic and acoustic sweep. Although the German vessel’s minehunting sonar passed right over it, the mine lay off to one side, not directly beneath the ship. Its plastic construction and rubberized coating didn’t return much of an echo, and it was missed.
Now Sachsenwald approached. She was on the third leg of her pattern, plowing through the river mouth’s choppy waters at twelve knots. The destroyer-sized pressure wave she created fulfilled the mine’s requirements, and the sounds her diesel engines made matched a set loaded into its memory. The weapon waited. There was still a chance that this enemy ship would not approach within lethal range.
The noise of Sachsenwald’s engines grew and grew. When the acoustic sensor’s calculations said it was close enough to inflict damage on the target, the mine armed itself. But it didn’t detonate yet. Although the German minelayer was only about seventy meters away, the noise level was still increasing as she drew nearer.
Sachsenwald plowed on, her twin mine chutes dropping packages at precise intervals. The mine listened, sensing but not understanding the thrum of the propellers and the clattering of her engines.
She passed ten meters to port and started to open the distance.
The Stonefish’s sensors picked up the drop in noise level and triggered the fuse.
Five hundred kilograms of PBX, half a ton of modern explosive, detonated on the seabed just thirty-two meters away from Sachsenwald’s steel hull.
The violence of the explosion knocked the ship almost all the way onto her port side. A massive column of dirty water shot fifty meters high into the air before cascading down on the heeled-over minelayer with crashing force.