Page 247 - NAVAL SCIENCE 3 TEXTBOOK

NAVAL W EAPO N S AND A I RCRAFT 253

as to the success of this field in sinking U-boats, but that it kept Allied ships were sunk by mines during the former connic!. The
them bottled up to it considerable extent is certain. This dlllnaged Viet Cong also used improvised controlled mines in the rivers of
German submariners' morale and simultaneollsly boosted the SOllth VietIlam, which they would detonate from shore whenever
morale of American and British merchant seamen upon whom a suitable target came within range. Later, drifting mines caused
wartime logistics depended. damnge to ships of several nations in the Persian Gulf during the
Postwar statistics re\'eal that mines sank more ships than did Iran-Iraq \·Var in the 1980s, and to sever.,1 U.S. warships during
torpedoes and gunfire combined during \\'orld \Var I. The cost of Operation Desert Storm in 1991.
the North Sea barrage was determined to be equal to the cost of
prosecuting the Will' for one day, so if it shortened the war by even
Mine C lassif ication
that much, it was a good investment.
Mine warli.ue of \Vorld \Var II featured offensive mine-laying ?\'lines are classified according to the method of planting (surface,
by both subm<1rines and <1ircmft. Defensh'e mining was carried aircraft, or submarine), the finnl planted position (moored, bottom,
out mainly by con\'entional types of surti.lCe minelayers, and mine or drifting), the mode of operation (controlled or automatic), and
clearance was done primarily by surti.lCe craft equipped with spe- the detonating or actuation mechanism (contact or influence).
cial mincsweeping gear. COllntermeasures included novel devices Method of planting. Mines can be planted b)' surface craft II'hen
for protection and detection. secrec}' is not of prime importance. High-speed minelayers can
In the opening months of the war, Nazi submarines and air- carry many mines and ciln lay a large minefield in a relatively short
cran sowed extensive minefields off the English and Scottish coasts. time. Presently, however, the U.S. Navy has no minelayers in COIll-
A number of British ships were sunk by this mine barrage, which missioned service.
was especially heavy in the Thames estuary. Early in the war, how- Planting mines by submarine can be accomplished with great
ever, the Germans lost one of their secret weapons, an influence secrecy and at great distances from home ports. Once the mine-
mine designed to be triggered b)1 the magnetic field of a passing field has been laid, however, friendly submarines cannot navigate
steel-hulled ship. The mine, dropped by an airplane, overshot its in the area dming the armed life of the planted mines.
mark and landed intact in a mud bank. The British recovered the Aircraft-planted mines C1I1 be carried and released like bombs
mine and shortly thereafter produced a successful countermea- or torpedoes. A parachute is attached to the mine to slow its
sure, doubtlessly saving countless Allied ships. descent; the parachute separates from the mine case and sinks on
Japanese minefields in the Pacific during the wnr were also impact with the water. Aircraft can carry mines into enemy-held
quite extensi\'e. They used defensi\'C minefields to protect their areas, and the field call be replenished, if necessary, without dan-
major bases and harbors. Their minefields west of the Nansei Shoto ger from previousl), planted mines. There is little secrec)' in planting
protected shipping in the East China Sea throughout the war. Until aerial mines, though night-flying planes can be used to some extent.
the last months of the war, the Sea of Japan was effectively sealed Aircraft can mine coastal and shallow waters that no other pliltfonn
off from American submarine and surface ships by Japanese fields could possibly mine. Blockading enem), shipping lanes and harbors
in the stmits leading into that body of water from the Pacific. Both can be very efiectiveiy accomplished b}' this type of mining.
the Americans and the Japanese laid ofiensive fields to destroy or Planted position. Moored mines have buoyant cases contain-
divert enemy shipping. ing the explosive charge. The)' are kept at a predetermined depth
During the Korean and Vietnam wars, Communist forces b)' mooring cables attached to an anchor. Because the depth of
floated mines dowll rivers into harbors and out to sea. Se\'eral the mines (;,111 be controlled by the length of their mooring cables,
the mines can be deployed in shallow w"ter against small craft, or
in deeper water against major stJJ'face ships and submarines. The
main disadvantage is that they mily be cleared with comparative
ease by mechanical sweeping gear.
For that reason, bottom mines were developed. They can be
planted b)' an)' t)'pe of crali, and because the)' lie on the bottom,
they require cosll}, minesweeping gear to detect and rel110ve them,
both diflicult tasks. The), cannot be planted in lI'ater depths greater
than 30 fathoms, unless intended as antisubmarine weapons.
Drifting mines are IlOt actually planted, in the true sense.
Often, however, it drifting mine is a moored mine that has broken
loose from its mooring cable and has become a hazard to all inter-
This ship was the victim of a Viet Cong mine floated down the Long
Tau River leading to Saigon during the Vietnam War. national navigation, neutml and belligerent alike.