Editor's note: Just before the United States entered each of the world wars, New London was visited by a foreign submarine. Neither was what it seemed, and both brought wartime intrigue to the Whaling City. November marks the 100th anniversary of one visit and the 75th of the other. This story is drawn mostly from "The Merchant U-Boat" by Dwight R. Messimer and the archives of The Day and the New London Telegraph. First of two parts.

The headlines sound routine enough if one just reads the words: "U-boat Deutschland is here" in The Day, and "Deutschland arrives from Bremen" in the New London Telegraph.

But stretched across front pages in end-of-the-world type, they don't just announce, they scream.

When New Londoners awoke on Nov. 1, 1916, and found a German submarine on their waterfront, the city went into celebration mode. The visitor had long been anticipated, but no one knew when, or even if, it would arrive.

The fact that German U-boats were sinking British ships — as well as the occasional neutral American — was of little concern. This was a different kind of submarine, on a different kind of mission.

The Deutschland, 213 feet long with a beam of 29 feet, was perhaps the plumpest undersea vessel ever built. Not a warship, it was a freighter, but what it carried mattered less to New London than what it signaled: a new era of prosperity.

In the midst of a world war, New London's civic leaders had spent months touting a most improbable venture: a trans-Atlantic shipping company with New London as its American terminus. Across the ocean war zone, cargo would ride safely beneath the waves in undersea merchant ships.

Since August, the eyes of New Londoners had turned regularly toward Ledge Light in the hope that the first ship would come into view. Now, finally, it was here.

When Paul König, Deutschland's captain, left the Custom House on Bank Street after registering his ship, he was mobbed by a crowd that stopped traffic. He accepted flowers and posed for photos.

Later he welcomed a delegation headed by the mayor and invited them to inspect the ship. In return, city officials planned a banquet at the Crocker House to honor the crew.

Tickets sold out immediately, but given the tense state of U.S.-German relations, the idea didn't sit well with everyone, including manufacturer George S. Palmer.

"We certainly should not be giving loving cups to officers of German submarines who at some future time may possibly make their presence known to us by torpedoing without warning American merchant ships in sight of our shores," he wrote.

But on Nov. 8, fully 4,000 people filed through the City Hall lobby to shake König's hand. At the banquet, he was given a gold watch as speakers imagined a glorious postwar day when German liners would sail from New London.

* * *

The excitement had been building for five years. In 1911, Bryan F. Mahan, who was both mayor of New London and a state senator, achieved the near impossible. He got the legislature to appropriate the unthinkable sum of $1 million for the city.

New London planned a steamship terminal to exploit its deep-water port. Construction on the massive project, now known as State Pier, was nearing completion in mid-1916 when Deutschland made its first journey to the United States, delivering a commercial cargo to Baltimore.

The visit was national news, and just after Deutschland began its return trip in August, it was announced that the famous vessel's sister ship, Bremen, was underway with a second cargo. To the astonishment of all, Bremen's destination was not Baltimore, but the still-unfinished State Pier, which had been secretly leased by German interests.

A warehouse was hammered together on the pier in less than two weeks, and an interned German liner, the Willehad, arrived to block the submarine from view. All anxiously awaited Bremen, but it never arrived and was soon declared lost.

Months of anticipation followed until Deutschland's surprise appearance on Nov. 1.

Amid all the hoopla, there were quiet doubts that Deutschland was indeed a commercial vessel. It was unarmed but manned by 28 men of military age with submarine training.

A Navy inspection concluded the submarine, with its ample cargo space, could easily serve as a tender to supply and refuel other U-boats. The implications threatened to complicate American neutrality.

In Baltimore, the U.S. government had recognized Deutschland as a merchant vessel over British protests that it could not be stopped and searched under wartime rules.

In fact, Deutschland was secretly a part of the German war effort. Its crewmen were sailors in the Imperial German Navy, and its status as a commercial vessel was nothing but a convenient fiction.

So, by extension, was the idea that the sub's arrival was the start of something big for State Pier.

* * *

In the early morning dark of Nov. 17, Deutschland glided down the Thames, escorted by two tugs. Having unloaded its cargo of dyes and pharmaceuticals and taken on a shipment of silver, nickel and rubber, it was headed home.

But at 3:30 a.m., the strong currents of the Race suddenly pushed one of the tugs into the path of the submarine, which had no time to react. Deutschland rammed the port side of the tug and cut the smaller vessel in two.

Five men aboard were killed, and a sixth survived only because he was hurled into the frigid water, where he nearly drowned.

Deutschland retreated to its berth behind the Willehad as the city's jubilation turned to grief.

"Before such a sudden catastrophe ... the community stands appalled," the Telegraph editorialized. "It sometimes requires an effort of will to convince ourselves that it is not all a hideous dream that will be proved untrue."

As Deutschland's bow was lifted from the water for repairs, lawsuits flew and the sub was impounded, its crew briefly banned from going aboard.

But within three days, it was cleared for departure as lawyers wrangled over who was liable for the lives lost.

As Deutschland eased away from State Pier on Nov. 21, the crew stood on deck and waved their caps for the newsreel cameras as if nothing had happened.

* * *

A gang of stevedores arrived at State Pier in January 1917, and all signs pointed to the imminent arrival of Deutschland on its second trip to New London.

In Germany the sub was ready to sail when the trip was canceled. The war situation was about to change drastically.

The Germans planned to resume unrestricted submarine warfare in an attempt to make short work of the British. But they knew the move was likely to bring the United States into the war.

Deutschland never returned to the United States. It was converted to a warship and — as George S. Palmer had predicted — sank 42 Allied vessels.

But its aborted second trip to New London had consequences that loom large. In addition to cargo, the sub would have carried diplomatic correspondence. According to Pulitzer Prize-winning historian Barbara W. Tuchman, this would have included a message from the German foreign minister to one of his Western Hemisphere ambassadors.

Because Deutschland's second trip was canceled, the message had to be delivered by telegram. It was sent in a code so new that in November, Deutschland had delivered the codebook to Germany's U.S. ambassador, who had come to New London to greet the submarine. But other embassies didn't yet have the book, so the message was resent in an older code.

What the Germans didn't know was that the British had long since broken the earlier code. When they intercepted the message, they knew it was dynamite.

In the event the U.S. entered the war, Germany instructed its ambassador to propose an alliance with Mexico. Once the Americans were defeated, Mexico would conquer Texas, New Mexico and Arizona, which it had lost to the United States in the 19th century.

When the message, known to history as the Zimmermann Telegram, became public, it sparked outrage and was one of the main reasons the U.S. declared war on Germany.

We'll never know what might have happened had the message been delivered secretly on Deutschland's return trip to New London.

j.ruddy@theday.com