Historic California
Posts, Camps, Stations and Airfields
Forts Under the
Sea
Submarine Mine
Defense of San Francisco Bay by Gordon Chappell
Regional Historian, Pacific West
Region
National Park Service
Today the term, "torpedo" means
to the average American a self-propelled underwater missile which
can be fired from a submarine or launched into the water from
the deck of a cruiser, destroyer, patrol torpedo boat, or other
vessel, to destroy enemy ships. It was not always so. Historically
the term "torpedo" meant what we now know as the underwater
explosive mine. Torpedoes of this sort were originally of two
basic types: anchored under the sea by cables, they were fired
by electrical charges controlled by a switchboard on shore; or
they were self-fired by physical contact with an enemy vessel
which bumped into them, or in later and more sophisticated versions
by magnetic fields, acoustics or other devices triggered by the
mere proximity of a vessel. The "contact" torpedo frequently
was laid in offshore minefields to deny use of the seaward harbor
approaches to enemy vessels, or in enemy waters to block ship
channels, and these, once laid, were more or less free agents,
anchored in place but not under actual control even of the nation
which laid them, other than to the extent that their location
was known and mapped. But the kind of torpedo or mine that was
fired from shore commonly was used in or just outside the harbor
they protected. These were harmless to vessels passing even directly
over them, unless that switch on shore was closed to fire them
beneath an enemy ship.
Torpedoes, later called mines, were an
American invention. An unsuccessful attempt was made to destroy
a British warship with one as early as the Revolutionary War.
Robert Fulton blew up a small vessel with one early in the 19th
Century. In the 1830s and 1840s Samuel Colt, inventor of the
revolver, perfected means of firing an underwater explosive charge
using electricity, and invented an electrical cable capable of
being used under water. Following the Civil War, Lieutenant Colonel.
Henry L. Abbot of the Corps of Engineers carried out a long series
of experiments in submarine mining at Willets Point, New York,
formulating the system that later would be used by engineers
in San Francisco Harbor.
Since it was the Corps of Engineers which
pioneered in developing torpedo defense systems, responsibility
for their installation and management remained for some years
with the engineers. In 1903, however, the responsibility was
transferred to the Coast Artillery Corps, and it was not until
1949 that responsibility for harbor defense minefields were transferred
to the U.S. Navy, only one year before the Coast Artillery Corps
was disbanded, air power having left it obsolete.
It was in June 1883 that the first shipment
of "buoyant torpedoes" to San Francisco was made, and
they temporarily were stored in the pier casemate at Alcatraz,
until a concrete torpedo storehouse, completed about 1889, could
be planned and built on the northern end of Yerba Buena Island.
(The storehouse still stands, nearly beneath the approach of
the Bay Bridge to the north side of the island and its highway
tunnel.)
Electrically fired "torpedoes"
or mines required a control room from which cables ran out into
the water and from which an operator sent the electrical impulse
to fire the mine. These were termed mine or torpedo casemates.
In 1889 funding was provided to construct the first two of these
in San Francisco Bay, one on Alcatraz and one at Fort Mason.
The Alcatraz casemate was simply an adaptation of part of an
existing structure, but an entirely new Fort Mason torpedo casemate
was built in 1890, and still exists. Mines were not actually
placed until the stimulus of the Spanish American War, when 28
harbors nationwide were mined; among West Coast harbors, San
Francisco's was the only one to have that defense. Its first
mine was planted on June 11, 1898, and mine planting continued
until July 16, when 63 had been emplaced but the armistice of
August 12 resulted in subsequent picking up of the mines, which
were cleaned and again stored in the Buena storehouse by November
1898.
To plant the mines the army used tugboats,
lighters and other small craft until April 16, 1909, when two
of the army's first class of especially designed mine planters,
the Armistead and the Ringgold steamed through
the Golden Gate. Thereafter such special vessels did the work.
Meanwhile, new mining casemates were built
and some old ones abandoned. One was added north of Point Cavallo
and a fourth near Mortar Hill on Angel Island. In 1897 a fifth
was constructed, this one at Quarry Point on Angel Island.
When on March 31, 1903, responsibility
for mines in San Francisco Bay transferred from the Corps of
Engineers to the Coast Artillery Corps, the artillery command
was unhappy with the location of the mine depot on Yerba Buena
Island, although Engineers argued that there it was protected
by all the defenses of the Bay, including the minefields. But
the artillery wanted it relocated farther west, so between 1907
and 1910 a new depot and wharf were built a short distance east
of Fort Point. Although poorly located and designed, this depot
nevertheless served through World Wars I and II and most of its
buildings still stand. New mine casements were built, one at
Fort Barry in 1908, one at Fort Baker in 1909, and one at Baker
Beach in Fort Winfield Scott in 1912. Planned since 1918, the
final modernization was construction of an entirely new mine
depot and wharf to supplement and eventually replace the one
near Fort Point. Construction began in 1937 on the west side
of Horseshoe Bay at Fort Baker and the new depot was essentially
finished in 1941. A new mine casement at Baker Beach was built
in 1943. The minefields were protected against enemy mine sweepers
by rapid fire batteries and searchlights which provided nighttime
illumination.
Map Courtesy of Brian
Chin
Fields of both shore-controlled mines
and some contact mines were planted near San Francisco during
the late 1930s and early 1940s, being finished after America
entered World War II on December 7, 1941. By the end of the war
in 1945 the harbor was protected by 37 mine groups with 13 mines
in each group, or 481 mines. But World War II, which brought
harbor mine defense to its highest state or perfection, also
spelled its doom, for air power demonstrated so effectively in
that war left both coast artillery and shore-controlled under
water mines obsolete in American defense.
Army mine-planting crew hauls
up a seaweed-covered buoyant mine. Each mine carried 800-pounds
of TNT and was connected by electric cable to a shore-based detonating
station. When a vessel struck a mine, an impact-sensitive device
in each mine sounded the alarm in the control bunker. The order
could then be given to detonate the mine and blow up the vessel
which hit it. Photograph courtesy of Brian Chin
The
Army Mine Planter Service
As a result of the Appropriations Act
of July 9, 1918, the rank and grade of warrant officer was officially
established. War Department Bulletin 43 dated July 22, 1918 stated:
"..in the Coast Artillery Corps of the Regular Army a service
to be known as the Army Mine Planter Service, which shall consist,
for each mine planter in the service of the United States, of
one master, one first mate, one second mate, one chief engineer,
one second assistant engineer and one assistant engineer, who
shall be warrant officers appointed by holding their office at
the discretion of the Secretary of War." Although no warrant
officer rank insignia was authorized, a sleeve insignia to identify
the job specialties was created by War Department Circular 15
on January 17, 1920. The sleeve insignia had a three-bladed propeller
or foul anchor above the braid as shown below. This insignia
remained in effect until the Mine Planter Service was abolished
on June 30, 1947.
Master
Chief Engineer
First Mate
Assistant Engineer
Second Mate
Second Assistant Engineer
Those who served at the San Francisco
harbor defenses fondly remember the mine planter Niles,
one of the most graceful ships to serve in the Army mine planter
service. This vessel was equipped with davits and other specialized
gear to plant mines and maintain them. The crews which served
aboard mine planters were all Army personnel. This ship mounted
several .50-caliber machine guns for protection on the high seas.
The Niles, along with two other mine planters, were permanently
assigned to the San Francisco defenses during World War Two
Photographs courtesy
of Brian Chin
Many smaller boats aided the mine planter
ships in mining operations off the harbor entrance. Some mine
planter soldiers were recruited from the crab fishermen of San
Francisco's famed Fisherman's Wharf. Occasionally, in course
of their mine planting duties, these men also planted crab pots.
The resulting crab bounty provided the dinner for the big gun
defense batteries which chipped in for crab bait.
Fort Baker's Mine
Depot, now part of the Coast Guard Station, Golden Gate. October
2000
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