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  2. Submarine depth ratings - Wikipedia

    en.wikipedia.org/wiki/Submarine_depth_ratings

    This is the maximum depth at which a submarine is permitted to operate under normal peacetime circumstances, and is tested during sea trials.The test depth is set at two-thirds (0.66) of the design depth for United States Navy submarines, while the Royal Navy sets test depth at 4/7 (0.57) the design depth, and the German Navy sets it at exactly one-half (0.50) of design depth.

  3. Maximum operating depth - Wikipedia

    en.wikipedia.org/wiki/Maximum_operating_depth

    Maximum operating depth. In underwater diving activities such as saturation diving, technical diving and nitrox diving, the maximum operating depth (MOD) of a breathing gas is the depth below which the partial pressure of oxygen (pO 2) of the gas mix exceeds an acceptable limit. This limit is based on risk of central nervous system oxygen ...

  4. Chart datum - Wikipedia

    en.wikipedia.org/wiki/Chart_datum

    A chart datum is the water level surface serving as origin of depths displayed on a nautical chart and for reporting and predicting tide heights. A chart datum is generally derived from some tidal phase, in which case it is also known as a tidal datum. [1] Common chart datums are lowest astronomical tide (LAT) [1] and mean lower low water (MLLW).

  5. Depth sounding - Wikipedia

    en.wikipedia.org/wiki/Depth_sounding

    Depth sounding, often simply called sounding, is measuring the depth of a body of water. Data taken from soundings are used in bathymetry to make maps of the floor of a body of water, such as the seabed topography. Soundings were traditionally shown on nautical charts in fathoms and feet. The National Oceanic and Atmospheric Administration ...

  6. Vertical datum - Wikipedia

    en.wikipedia.org/wiki/Vertical_datum

    Vertical datums in Europe. In geodesy, surveying, hydrography and navigation, vertical datum or altimetric datum is a reference coordinate surface used for vertical positions, such as the elevations of Earth-bound features (terrain, bathymetry, water level, and built structures) and altitudes of satellite orbits and in aviation.

  7. Ascending and descending (diving) - Wikipedia

    en.wikipedia.org/wiki/Ascending_and_descending...

    Diving stage used to control ascents and descents of surface-supplied divers. In underwater diving, ascending and descending is done using strict protocols to avoid problems caused by the changes in ambient pressure and the hazards of obstacles near the surface such as collision with vessels. Diver certification and accreditation organisations ...

  8. North American Datum - Wikipedia

    en.wikipedia.org/wiki/North_American_Datum

    The North American Datum (NAD) is the horizontal datum now used to define the geodetic network in North America. A datum is a formal description of the shape of the Earth along with an "anchor" point for the coordinate system. In surveying, cartography, and land-use planning, two North American Datums are in use for making lateral or ...

  9. Trieste (bathyscaphe) - Wikipedia

    en.wikipedia.org/wiki/Trieste_(bathyscaphe)

    Trieste is a Swiss-designed, Italian-built deep-diving research bathyscaphe. In 1960, it became the first crewed vessel to reach the bottom of Challenger Deep in the Mariana Trench, the deepest point in Earth's seabed. [2] The mission was the final goal for Project Nekton, a series of dives conducted by the United States Navy in the Pacific ...