Page 42 - NAVAL SCIENCE 3 TEXTBOOK

N AVAL OPERATIONS AN D SUPPORT FU N CTIO NS 47

matical process called triangulation, the submarine's location could
then be pinpointed by the sounds of its engines and propellers.
Finally, the depth chalge gave the destroyer a weapon that
could destroy a submarine underwater. Essentially a large canister
of high explosives, the depth charge could be rigged to detonate at
a preset depth.
American scientists improved on the hydrophone system dur-
ing World War II, calling it the sound navigation and ranging sys-
tem (sonar), or underwater sound ranging system. By bouncing
sound pulses off the hull of a submarine and measuring the time
lapse until the return of their reflections, the range and bearing
of the submarine could be determined almost exactly. The sci-
ence of underwater sound has continued to advance. Using sonar
ranges and bearings to contacts, computers can quickly figure their
courses and speeds, and if necessary program weapons to attack
them, taking into account such variables as water temperature,
salinity, and pressure.
Since World War II significant advances in USW have been
made. The helicopter has become a major USW platform. The
highly maneuverable nuclear-powered attack submarine (SSN) has
become the most effective USW vessel. The SSN can use sophisti-
cated sensing devices to find and attack enemy submarines with
homing torpedoes and a variety of long-range missiles (including An aviation ordnanceman loads disposable radio sonobuoys into a
subsurface-to-subsurface types). P-3 Orion patrol aircraft. The sonobuoys can be dropped on the water
Modern cruisers, frigates, destroyers, and USW aircraft, both around a suspected submerged submarine, allowing an operator on
the aircraft to track its movements. (John Coli ins)
shore-based and carrier-based, have a variety of sensors to locate
and attack submarines. Some of these include the following:
throughout history, including the American Revolution and the
Radio sonobuoys, which contain a hydrophone and radio
Civil War. Undoubtedly the most famous amphibious operation
transmitter to help locate submarines by transmission of a
of World War I was the ill-fated Allied invasion of the Gallipoli
submarine's noises to the aircraft
Peninsula in the Turkish Straits. There, logistics and communica-
Magnetic anomaly detection (MAD) gear, which detects
tions were inadequate, heavy mining caused major ship losses, and
variations in the Earth's magnetic lines of force created by a
strongly entrenched Turkish forces could not be driven from their
submarine
fortifications. The lessons learned from the disastrous Gallipoli
Dipping sonal; a device lowered into the sea from a hovering campaign assisted in the development of modern amphibious
helicopter to echo-range a submarine warfare doctrine.
Infrared detection, a method involving electronic detection of In World War II amphibious operations were developed into
heat emitted from submarines a highly refined military science. Dozens upon dozens of land-
ings took place in the Pacific against strongly held Japanese islands.
Towed arrays of sensors that can be streamed behind warships
Lessons were learned from mistakes made in the early assaults,
to detect low-level sound emitted from submarines at long
and eventually a smoothly functioning Navy-Marine Corps team
range
operation developed. In the European theater, landings were even
Once detected, the submarine can be attacked with depth charges, larger in scale, involving hundreds of thousands of troops in the
antisubmarine missiles, and homing torpedoes. invasions of North Africa, Sicily, Italy, and France. The invasion of
Normandy in France brought ashore I million men, 183,000 vehi-
cles, and 650,000 tons of supplies from 3,000 vessels in the first
Amphibious Warfare
twenty-eight days of the assault!
Amphibious warfare, like surface warfare in general, goes back Amphibious warfare uses nearly all types of ships, aircraft,
for centuries, to the ancient Greeks and their assault on Troy. weapons, and landing forces to carry out a coordinated military
Amphibious assaults and withdrawals have played key roles attack against a hostile shore from the sea.