Sub designed to beat WWI blockade

Germany designed merchant subs.

By LEUT Aaron Matzkows

Blockades of enemy ports during war time tend to develop that peculiar kind of person and ship, the blockade runners.

In World War I, the Royal Navy’s efficiency at cutting off German ports and capturing merchant vessels bound for Germany had reduced the country’s capacity both to make war and feed itself.

Toward the end of 1916, the situation in the country was getting desperate.

The typical daily food ration was, according to one civilian, “five slices bread, half a small cutlet, half a tumbler of milk, two thimblefuls of fat, a few potatoes and an eggcup of sugar”.

Desperate times call for desperate measures and more than a little ingenuity and a German naval architect came with a stunning solution.

In 1916, Germany created the ultimate World War I U-boat, developed with private funds.

It was a true longrange submarine cruiser, designed as a merchant vessel.

Boats of the UA class were 230 feet long, about 1500 tons, with a speed of 15.3 knots on the surface and a range of 12,630 miles at 8 knots.

The first UA class blockade-breaking civilian cargo submarine was the Deutschland, operated by the North German Lloyd Line.

The Deutschland was unarmed and had a wide beam to provide space for a cargo capacity of 700 tons, small if compared with surface ships, but equal to that of seven modern C-5A transport aircraft.

She was designed for high-value trans-Atlantic commerce, submerging to avoid British patrols.

On her maiden voyage, she managed to slip through the British blockade with a cargo of dyes, chemicals and precious stones bound for still-neutral America, arriving in Baltimore harbour in July 1916 after four weeks at sea.

The voyage was a remarkable propaganda coup and profitable as well, with Deutschland returning to Germany with a valuable cargo of nickel, tin, and crude rubber, much of it stored outside the pressure hull.

Another mercantile submarine, the Bremen, departed for America, but disappeared en-route, apparently sunk by a mine north of the Orkneys.

The Bremen had been escorted by the conventional submarine U-53. Some of the U-53’s ballast tanks had been converted to carry extra fuel to allow it to make the trip.

U-53 continued to the east coast of the US, where her commander, Lieutenant Hans Rose, decided to demonstrate just how fearsome Germany’s U-boats were by sinking three British, one Norwegian, and one Dutch merchantmen just outside US territorial waters.

He had apparently intended to intimidate the Americans, but instead largely succeeded in antagonising them.

The Deutschland made a second merchant trip in November, 1916, making landfall in New London, Connecticut, but anti-German sentiment was raging in the US by then and no more merchant voyages were undertaken.

Three months later she had been converted and sent to war as U-155.

She was given two torpedo tubes and a 150mm (5.9 inch) deck gun and six remaining boats of the class under construction were finished as warships.

Their armament was twin 150 mm deck guns, 1000 rounds of ammunition and 19 torpedoes. The seven UAs, manned by crews of 56 with room for 20 more, were designated U-151 to U-157.

The US entered the war in April 1917.

Six UA boats were deployed to the East Coast of the United States, where they laid mines and sank 174 ships, mostly smaller vessels without radios which could neither be warned or give warning.

The UAs had proved that a submarine could operate 3000 miles from home base, but they had little impact on the movement of troops and supplies to Europe.

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