Plunger was the first unit of the A-class, commissioned in 1903 as USS A-1.  On 22 August 1905, Plunger, accompanied by a tug, visited Oyster Bay New York and hosted a 3 hour visit by President Theodore Roosevelt.   On 3 May 1909, Ensign Chester W. Nimitz, the future Fleet Admiral, took command of Plunger. That September, the submarine visited New York City to take part in the Hudson-Fulton celebrations.

In October, Plunger and two submarines of a newer class, Viper (USS B-1) and Tarantula (USS B-3), accompanied by a gunboat as tender, were transferred to Charlestown to establish a submarine division there. Enroute, Viper had a mishap and made an unscheduled landing on Cape Henlopen.

By 1911, the Navy had acquired 20 Holland-type boats on the East Coast. As the Navy began investigating different design characteristics for its subs, the next class was built at other yards.   Thrasher (USS G-4) was built at Cramp’s shipyard in Philadelphia and commissioned in 1914.

Based on plans purchased from an Italian designer, and with different equipment requiring different operating procedures, Thrasher  spent the next five months conducting trial runs and diving tests in the vicinity of Cape Henlopen.

Then, in 1915, Thrasher participated in a Naval Review for President Wilson and during the war served as a developmental submarine for new submarine detection equipment.

As WW I raged in Europe, the Germans conducted submarine warfare to isolate Great Britain from receiving supplies. But, in response to a warning from President Wilson, they placed restrictions on their campaign in an effort to keep the U.S. out of the war.

However, recognizing that the threat of submarine warfare off the U.S. coasts might serve as a deterrent to U.S. entry into the war, the Germans took the opportunity to demonstrate their long-range submarine capabilities. German commercial enterprises had undertaken the construction of cargo-carrying submarines to carry critical supplies to Germany, avoiding the Royal Navy blockade.  Seven submarines were planned, the first was the Deutschland.

In 1916, Deutschland made the first-ever submarine trans-Atlantic crossing, arriving in Baltimore in early July. The sub made another trip to New London.  On these voyages, each of over 8000 nautical miles, the submarine was only submerged for the undetected passage of the English Channel.

At the time of the Deutschland’s visit, the Navy took the opportunity to announce the completion of the newest and largest U.S. submarine, the USS M-1. The next Spring while on training, the M-1 operated in the Cape area.

After abortive peace overtures, on February 1, 1917 Germany again began unrestricted submarine warfare. And, after the first two American ships were sunk, President Wilson declared war.  At the time, Germany had 111 U-boats.   In the Atlantic, the U.S. had a total of 40 submarines plus 7 coastal N-class boats.

The first warnings of German submarines approaching the Cape and moving toward Fourth Naval District (4ND) waters, for which the Inshore Defense Forces based at Cape May and Lewes were responsible, came in mid-May 1918.  The submarine was the Deutschland, now converted to a minelayer, U-151.

During May, the sub operated undetected by U.S. naval forces while attacking several coast-wise sail schooners unlikely to have radios.  These attacks were carried out by the surfaced sub using its deck guns to fire a warning shot to stop the ship, then telling the crew to abandon ship and taking them prisoners.  The sub's crewmen boarded the abandoned ship to place explosives to sink it.  In that way there was little chance for the Navy to receive warning of the sub's location.  At the end of May, the undetected U-151 laid a cluster of mines off Cape Henlopen and continued north to cut a trans-Atlantic cable off New York.  Then, on 2 June, on what came to be called “Black Sunday”, the sub sank three more schooners and three steamships as well as damaging two other ships off the coast of New Jersey about 50 miles southeast of Barnegat light. 

The last ship sunk was the SS Carolina, a 5000 ton passenger ship with 200 passengers and 100 crew. As the passengers and crew of that ship and the other ships took to the lifeboats, the prisoners aboard the sub were released to join them. Thus, some 400 people were adrift in boats off New Jersey.

On 3 June, the war came to the Cape.  First, early in the day, a British ship carrying survivors from Carolina arrived at the Cape.  Those survivors had been in two life boats that had been caught in a squall overnight.  One of the boats had capsized, resulting in the loss of 13 persons.

Then, later in the day, the Herbert L. Pratt, a 7150 gross ton oil tanker, proceeding empty to Philadelphia for delivery to the Navy, hit one of the mines laid by U-151 when about three miles off Cape Henlopen near the Overfalls lightship.  The explosion ripped a hole in her forward section which quickly submerged. 

The Lewes pilot boat Philadelphia, soon arrived to evacuate crewmen.  Some remained aboard and, with a salvage crew, righted the ship.  A Navy tug towed it into the Naval Section Base at Lewes were it was patched and had power restored.  The ship then proceeded to Philadelphia under its own power.  Soon Pratt had been commissioned in the U.S. Navy, and was on its way to France with oil for ships based there.  

In July and August, three other Deutschland-type subs operated in the Cape area.  U-156 sunk one ship off northern New Jersey before moving north.  U-140 sunk one ship further at sea before moving south.

Next U-117,  nearing the middle of what had already been a very successful cruise, entered  Cape area waters, sinking one tanker and then another off Barnegat Light and then laying mines in the area.

On the way south past the Cape the sub was attacked by a Navy plane and subchaser. After escaping to sink a small coastal schooner, U-117 laid more mines in the area of Fenwick Light.    She then moved south to create more havoc. 

As a response to the continued German submarine operations off the Cape, in August 1918, the submarine tender USS Savannah (AS-8), flying the flag of Commander, Submarine Division 8, had arrived at the Delaware Breakwater.  The intention was to rendezvous with eight O-class submarines that had been operating out of the Philadelphia Navy Yard and provide an advance base for expanded operations and training before moving overseas.

Soon, however, it was found that the ground swell coming into the Harbor of Refuge from seaward made that area unsuitable as a floating base.  The division’s base was shifted to Cold Spring Inlet, Cape May. But, a unique ship of the squadron remained at the Lewes Naval Section Base.  That was the USS Robert H. McCurdy (ID 3157).  She was a 735 gross ton four-masted schooner intended to be a “decoy ship” mimicking the types of ships that had been attacked by U-151 and luring German subs into range of waiting U.S. subs.

When those submarines left the Cape in October for transfer overseas, they were replaced by several other O-class units that operated out of Cape May until 1919, before moving to Philadelphia.

On 18 September, a month after U-117 had left the area, the USS Minnesota (BB-22), an older battleship serving as a training ship, hit one of the mines laid by U-117 off of the Fenwick lightship.  The ship was able to contain the damage and proceed to the Cape and Philadelphia under her own power.

But, even long after U-117 had departed, the effects of her visit remained.  Two merchant ships were sunk in October off Barnegat Inlet by the mines that U-117 had laid earlier. Then, just as the war was ending, on 9 November, USS Saetia (ID No. 2317) a Navy support cargo ship encountered another of U-117’s mines and sunk 10 miles southeast of Fenwick Island Shoal.  All eighty-five hands survived to come ashore at Ocean city and Cape May.

Some of the mines laid by U-151 and U-117 were still being found in early 1919.

In the post-war years, at least eight L-class subs were based at Philadelphia and frequently passed the Cape to operate along the Atlantic coast experimenting with new torpedoes and undersea detection equipment.

On February 2 1921, four of those Philadelphia-based L-class subs had been operating off the coast. Upon approaching the Cape for their return to Philadelphia, the subs encountered the Lewes pilot boat Philadelphia, which had seen their lights and mistakenly assumed it was a ship needing a pilot. Upon approaching the group, Philadelphia rammed L-1 and damaged it enough so that it was in danger of sinking. Philadelphia towed the sub to the breakwater where it rested stern-down on a muddy bottom in shallow water.  The crew stabilized the sub and it was towed to Philadelphia by the Navy tug, USS Kalmia (AT-23).

In the post-war era, the R-class was the principal fleet submarine and a newly-designed S-class was being built. One of the earlier units of this class, S-5, was to conduct Navy trials about 55 miles east-southeast of the Cape while enroute to Baltimore.  On 1 September 1920,  S-5 was to conduct a required four-hour, high-speed surface run, to be followed immediately by a crash dive and a one-hour, high-speed submerged trial.

When the order to dive was given, difficulties in regulating the valves caused the air intake valve to be left open momentarily too long.  Water poured through the ventilation system X, flooding the torpedo room. // The water in the torpedo room made submarine bow heavy and, despite emergency surfacing procedures, the submarine continued downward, plowing bow-first into the muddy bottom in 180-190 feet of water. 

After several hours of unsuccessful attempts to free the sub from the bottom, the Commanding Officer decided to use virtually all of the remaining pressurized air to empty water from the aft ballast tanks and make the stern more buoyant. The stern suddenly broke free of the bottom and, pivoting on the flooded and still-stuck bow, the submarine rotated vertically with the stern rapidly rising toward the surface until it was nearly 60 degrees from the horizontal.

By that time S-5 and her men had been on the bottom for nearly five hours.   Several men had remained in the motor room which, being at the stern of the sub, had become the highest compartment.  They reported hearing the sound of waves beating against the hull.  Given S-5’s 231 foot length, the 180-190 depth of water where she was marooned, and the angle she made with the horizontal, about 20 feet of the boat’s stern was protruding above the surface.

The commander and several crew members moved further aft into the tiller room and, using a manual drill, bored a quarter inch hole through the three-quarter inch, high-strength steel that separated them from the outside world. That work confirmed that the stern was well out of the water.  But, after 12 hours of hard work with hand tools in cramped spaces they had only succeeded in making a hole three inches in diameter.  After another 12 hours, drilling teams had achieved a triangular hole six by eight inches. But most of the men were now either incapacitated or unconscious from lack of oxygen.

Then, when all seemed lost, a ship appeared nearby.  Taking a ten-foot copper pipe and fastening a sailor’s tee-shirt to it, the commander thrust it out through the hole and waved  for help.  That was noticed by the small coastal steamship SS Alanthus, which came alongside  

 Alanthus had few tools and no radio but a large passenger steamship, the SS General George W. Goethals, was also passing nearby and Alanthus was able to contact her by emergency flaghoist.  Goethals radioed the Navy for assistance and her engineers created an 18 inch hole through which the crew could be brought out one by one.

About 36 hours after the casualty and just as a Navy tug and the battleship USS Ohio were arriving, the entire crew had been rescued.

The tug and Ohio rigged a towline and attempted free the sub, but as it filled with water it slowly sunk to the bottom, where it lies today.

As the S-class came into the Fleet, the R-class was phased out during the mid-1920s into the 1930s.  Many of those subs from the Atlantic Fleet passed the Cape enroute to Philadelphia for decommissioning and preservation in the Reserve Fleet.  Many were called back into commission for WW II.

Just like the R-class, O-class subs were being decommissioned in Philadelphia in the 1920s and 30s, ready to be recommissioned for future use.  

In July 1930 one, O-12, was struck from the Naval Register and  leased at a cost of one dollar per year for five years to be used in the Sir Hubert Wilkins Arctic Expedition.  The sub underwent extensive structural modifications and the installation of special scientific equipment at the Philadelphia Navy Yard.  During early March of 1931 builders trials, including diving, were conducted in the lower Delaware Bay.

As war was raging in Europe, U.S. naval preparations included the building of nine V-class submarines, modeled on the large long range German cruiser submarines of WWI.

Further, in 1940, the Navy allotted $22 million to reopen Cramp’s shipyard in Philadelphia for the construction of submarines of a new class of submarines based on the experience gained by building the V-class. The V-class sub, USS Cuttlefish (SS-171) was sent past the Cape to Philadelphia as an engineering model.

The first sub to arrive in that area after operating further north was U-123.   The u-boat spent 16 and 17 January lingering in the area of Five Fathom Bank on the surface at night looking at the lights of Cape May, Lewes and Rehoboth.  Fortunately, it found no targets and moved south.

Unfortunately, U-130 was not far behind.  That sub began the campaign sinking a foreign tanker and then U.S. tanker, which were the primary targets during the campaign.

In April and May in the ESF area, sinkings declined as the submarines began to operate south of Cape Hatteras in search of tankers. 

At about 8 PM on Wednesday 24 June, just as Cape area residents and vacationers were out for the evening or strolling on the Rehoboth boardwalk, an enormous explosion occurred just off the entrance to the Harbor of Refuge. 

The tug John R. Williams, returning to Cape May from a trip to Fenwick and failing to use the mine-swept channel, struck a mine laid by U-373 on 10 June.  The small size of the tug, 396 tons, did little to muffle the sound or contain the impact of the large size of the 2000 pound mine.  The sound was heard at a long distance and parts were strew over a wide area.  Only a lucky 4 of the 18 man crew survived.

As the German subs abandoned Cape waters, U.S.subs began transiting those waters enroute to war. some O-class and R-class that had been in reserve in Philadelphia passed the Cape outbound enroute to war, and S-class subs passed the Cape inbound to the Navy Yard for overhaul and refit before passing the Cape again going to war.

During the war, Cramp’s shipyard in Philadelphia built ten subs.  All of those subs did builders trials in Delaware Bay and off the Cape. Some, such as USS Sabalo (SS-302), also did Navy trials and training there before being commissioned at the Philadelphia Navy Yard.

Although German submarines no longer routinely operated operated in Cape waters, in February 1945, U-869 a Type XIC, boat heading toward the coast was attacked and sunk by USS PC-565 well off New Jersey.   Another Type XIC boat was also headed there as the war ended.

U-858 had been on patrol for 59 days without having made a single successful attack, when the war ended and it got the word to surrender.  The U-boat surfaced in mid-Atlantic near the USS Muir (DE-770) and USS Carter (DE-112).  Those ships turned the U-boat over to the USS Pope (DE-134) and USS Pillsbury (DE-133) who escorted it to the site of the sunken USS Jacob Jones where they accepted the surrender.  They  then escorted it to Fort Miles on the Cape where the surrender paperwork was accomplished.

The anti-submarine war was eventually won in mid-Atlantic by intelligence, surface ships and aircraft, but at great cost of men and material.  Meanwhile, the U.S. Navy carried on a successful submarine war in the Pacific.

When the war ended, many of the submarines that had performed so heroically in the Pacific returned past the Cape to Philadelphia to be put into reserve or for decommissioning.

In the early days of the Cold War, as the the U.S. Navy transitioned to nuclear powered submarines, Naval Submarine Reserve Units manning conventional submarines were maintained. 

Submarine Reserve Division 4-37 was based at the Philadelphia Navy Yard.  The first training submarine assigned to the division was the USS Hake (AGSS-256) and the second was USS Angler (IXSS-240). These submarines conducted training exercises in Delaware Bay and the waters off the Cape.  They ended their days in Philadelphia and ended the presence of submarines operating at the Cape.

 Photo Credits:

-Unless otherwise indicated ship pictures from Naval History and Heritage Command, Online Library of Selected Images.

-Deutschland: From Wikipedia.

-U-151: From "Fourth Naval District" in Philadelphia in the World War 1914-1918. (New York: Wynkoop, Hallenbedk Crawford Co., 1922).

-Charts U-151 and U-117 operations: From Department of the Navy, Office of Naval Records and Historical Secition; German Submarines Activities on the Atlantic Coast of the United States and Canada, (Washington DC: Government Printing Office, 1920). Accessed via www.fas.org/man/eprint/german-subs.pdf Annotated by author.  

-Carolina: From Wikipedia.

-Type IX sub: From: www.U-boat.com. 

-S-5: From Undersa Valor: In the Early Days of Undersea Salvage by Willard F. Searle and Thomas Gray Curtis, Jr.

-USS S-5 sidescan sonar image : From National Oceanographic and Atmosspheric Administration. www.noaa.gov.

-R-Class subs: From AP wire and philly.com accessed via www.navsource.org/photoarchive.

-O-12 in drydock: From http://library.osu.edu/site/exhibits/nautical/submarine.htm.

-Moray (USS-300): From Henry Kholer son of Harry F. Kholer EM!c plankowner USS Moray(SS-300) accessed via www.navsource.org/photoarchive.

-U-858:From Fort Miles by Dr. Gary Wray and Lee Jennings (Arcadia Publishing: 2005).  
-USS Narwhal: From USN photo accessed via www.navsource.org/photoarchive.

-USS Hake  and Angler: From John Hummel accessed via www.navsource.org/photoarchive.