Kantan-class / Bei Diao 993 / Dongyuan 03 Comprehensive Test Ship
North-adjusted 993, comprehensive test ship, unit of use: 760 (Shuisheng Institute), a comprehensive acoustic sound test ship for a variety of underwater acoustic equipment for marine testing. The construction of Jiangxi Jiangxin Shipyard was carried out in December 2000 in the Dalian Sea Area. The speed reached the design requirements and was delivered on December 28, 2000.
The total length of the ship is 86. meters, the depth is 6.8 meters, the width is 4 meters, the draft is 3.9 meters, the designed displacement is 2325 tons, the speed is 16 knots, the endurance is 2000 nautical miles, the self-sustaining power is 20 days, the crew is 30 people, and the test personnel are 70 people. The main engine is two 2200 kW diesel engines.
The first ball compartment of the bow has a sound-permeable function. It also has a side hull with a sound-permeable window. The upper part is equipped with a 20-ton lifting slewing device. The stroke reaches 9m underwater. The bow has 8 tons of cranes, 3 tons of slings and 5 tons of gantry at the stern, equipped with hydrodynamic winches, geological winches, line array winches, as well as wave detection systems, ADCP and other investigation devices. It has 4 laboratories with a total area of 120 square meters.
The middle part of the hull is equipped with an open-air well [a moon pool in Western parlance] with a diameter of 6.4m. The distinctive square framework forward of the main superstructure suppports moon pool operations. Several types of marine vessels are equipped with an opening in the base or bottom of the hull, that provides access to the water underneath the vessel. Typically, this opening extends from a deck on the vessel, through the hull, and to a portion of the hull bottom. An opening of this type is commonly referred to as a "moon pool". Moon pools are common in floating platforms that are used for drilling, production and/or maintenance of subsea oil and gas wells and associated subsea equipment. Drill strings, completion equipment, and various other tool and devices, are lowered into the water through the moon pool.
Moon pools are also common in drill ships and in diving support vessels and other offshore support vessels, including ships that are used for deploying and controlling subsea remotely operated vehicles (ROVs). Numerous vessels have been build using moon pools. These vessels include cable-laying vessels, pipe laying vessels and drilling vessels. The moon pool is a round hole, open to the sea, located amidships into which the pipe or cable is fed. When the ship wants to leave a site, the moon pool is typically closed, with hatches. These hatches are often large door like objects which are hinged to the sides or bulkheads of the vessels. The hatches have pins and objects which protrude outwardly when not locked together. These outwardly producing members have caused snagging and trouble in the industry.
The moon pool is indispensable for the function of the ship but becomes a weak point in view of the anchoring of the ship, the voyage stability and the voyage performance of the ship. Particularly, in a conventional ship, due to a sloshing phenomenon, which is induced by relative movement between seawater in the moon pool and seawater outside the ship, when the drill ship runs, resistance is increased, the velocity thereof is reduced, power consumption is increased, fuel consumption is increased, and the ship hull is damaged. A device for sealing a moon pool so that the vessel can quickly get underway with the minimum of snagging of lines.
Another disadvantage with open moon pools is the so-called "piston effect", in which the oscillating seawater column inside the moon pool generates a forced airflow out of and into the moon pool. This airflow may be uncomfortable and even dangerous to personnel in the vicinity of the moon pool. Another problem with open moon pools on vessels operating in arctic waters is interference with ice floe and ice chunks. These objects may enter the moon pool where they could cause damage to equipment and structures, and jeopardize operations through the moon pool.
|Name||North Adjustment 993 Comprehensive Test Ship|
|Service time||December 28, 2000|
|Manufacturing plant||Jiangxi Jiangxin Shipyard|
|design waterline length||81.50 m|
|Type depth||6.80 m|
|Type Width||14.6 m|
|engines||6M453C 3 sets, 3x2200 kW rated power|
|Endurance||1500 nautical miles|
|navigation area||Class I|
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