Marine

Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology. In scientific contexts, the term almost always refers exclusively to saltwater environments, although in other contexts (e.g., engineering) it may refer to any (usually navigable) body of water.

Marine or marines may also refer to:

Military / seafarers

Sea

A sea is a large body of salt water that is surrounded in whole or in part by land. More broadly, "the sea" is the interconnected system of Earth's salty, oceanic waters—considered as one global ocean or as several principal oceanic divisions. The sea moderates Earth's climate and has important roles in the water cycle, carbon cycle, and nitrogen cycle. Although the sea has been travelled and explored since prehistory, the modern scientific study of the sea—oceanography—dates broadly to the British Challenger expedition of the 1870s. The sea is conventionally divided into up to five large oceanic sections—including the IHO's four named oceans (the Atlantic, Pacific, Indian, and Arctic) and the Southern Ocean; smaller, second-order sections, such as the Mediterranean, are known as seas.

Owing to the present state of continental drift, the Northern Hemisphere is now fairly equally divided between land and sea (a ratio of about 2:3) but the South is overwhelmingly oceanic (1:4.7).Salinity in the open ocean is generally in a narrow band around 3.5% by mass, although this can vary in more landlocked waters, near the mouths of large rivers, or at great depths. About 85% of the solids in the open sea are sodium chloride. Deep-sea currents are produced by differences in salinity and temperature. Surface currents are formed by the friction of waves produced by the wind and by tides, the changes in local sea level produced by the gravity of the Moon and Sun. The direction of all of these is governed by surface and submarine land masses and by the rotation of the Earth (the Coriolis effect).

Marine biology

Marine biology is the scientific study of organisms in the ocean or other marine bodies of water. Given that in biology many phyla, families and genera have some species that live in the sea and others that live on land, marine biology classifies species based on the environment rather than on taxonomy. Marine biology differs from marine ecology as marine ecology is focused on how organisms interact with each other and the environment, while biology is the study of the organisms themselves.

A large proportion of all life on Earth lives in the ocean. Exactly how large the proportion is unknown, since many ocean species are still to be discovered. The ocean is a complex three-dimensional world covering approximately 71% of the Earth's surface. The habitats studied in marine biology include everything from the tiny layers of surface water in which organisms and abiotic items may be trapped in surface tension between the ocean and atmosphere, to the depths of the oceanic trenches, sometimes 10,000 meters or more beneath the surface of the ocean. Specific habitats include coral reefs, kelp forests, seagrass meadows, the surrounds of seamounts and thermal vents, tidepools, muddy, sandy and rocky bottoms, and the open ocean (pelagic) zone, where solid objects are rare and the surface of the water is the only visible boundary. The organisms studied range from microscopic phytoplankton and zooplankton to huge cetaceans (whales) 30 meters (98 feet) in length.

Marines

Marines, also known as a marine corps and naval infantry, are an infantry force that specializes in the support of naval and army operations on land and at sea, as well as the execution of their own operations. In the majority of countries, the marine force is part of the navy, but it can also be under the army like the Troupes de marine (French Marines) and Givati Brigade (Israeli Marines), or form an independent armed service branch like the United States Marine Corps and Royal Marines.

Historically, tasks undertaken by marines have included providing protection from war while at sea, reflecting the pressed nature of the ships' company and the risk of mutiny. Other tasks would include boarding of vessels during combat or capture of prize ships and providing manpower for raiding ashore in support of the naval objectives.

With the industrialization of warfare in the 20th century the scale of landing operations increased; this brought with it an increased likelihood of opposition and a need for co-ordination of various military elements. Marine forces evolved to specialize in the skills and capabilities required for amphibious warfare.

Sikorsky CH-53E Super Stallion

The Sikorsky CH-53E Super Stallion is the largest and heaviest helicopter in the United States military. As the Sikorsky S-80 it was developed from the CH-53 Sea Stallion, mainly by adding a third engine, adding a seventh blade to the main rotor and canting the tail rotor 20 degrees. It was built by Sikorsky Aircraft for the United States Marine Corps. The less common MH-53E Sea Dragon fills the United States Navy's need for long range minesweeping or Airborne Mine Countermeasures (AMCM) missions, and perform heavy-lift duties for the Navy. Under development is the CH-53K King Stallion, which will be equipped with new engines, new composite material rotor blades, and a wider aircraft cabin.

Development

Background

The CH-53 was the product of the U.S. Marines' "Heavy Helicopter Experimental" (HH(X)) competition begun in 1962. Sikorsky's S-65 was selected over Boeing Vertol's modified CH-47 Chinook version. The prototype YCH-53A first flew on 14 October 1964. The helicopter was designated "CH-53A Sea Stallion" and delivery of production helicopters began in 1966. The first CH-53As were powered by two General Electric T64-GE-6 turboshaft engines with 2,850 shp (2,125 kW) and had a maximum gross weight of 46,000 lb (20,865 kg) including 20,000 lb (9,072 kg) in payload.