Oceanographic Submersibles Oceanographic submersibles are small research vessels for underwater transport of peopl and equipment and for use as underwater platforms for observation, sampling, measurement, and performing various work tasks. They are also referred to as undersea vehicles. bout 100 crewed submersibles available for use around the world of these about 30 submersibles are available in the United States, the leading country in their development and construction. The highest concentration of submersibles is in support of the offshore oil industry mainly in the North Sea. The leading mission applications are inspection of pipeline and cables, followed by cable burial, salvage, coral harvesting, geology, fisheries, biology, and environmental Undersea vehicles are being utilized more now that experience has confirmed their utility, and systems are being designed in accordance with user requirements. A major trend pertains to designing a completely integrated system, which, in addition to the submersible, includes support ship, handling gear for launch and retrieval, and logistic and maintenance support. The(328) objective is to obtain an effective, high utilization rate under varying weather conditions. The major vehicle operating problem is handling during launch and retrieval in heavy seas. Equipment for conducting efficient deep-water surveys will systems. Manipulators with greater dexterity will be needed for human-occupied and unoccupied systems to perform intricate manipulative ith large panoramic ple windows to provide a wider viewing field, very effective in survey and inspection mission The ratio of the weight of structure to the sea-water weight for an equal volume determines of a submerged vehicle. This ratio is dependent on several items, one of the most important of which is the compressive strength-to-density ratio of the pressure hull material. Steel with a yield strength of 100000 psi(689500000N/m) is generally employed in vehicles Hull buoy Most small submersibles need buoyancy in excess of that produced by their pressure hulls to attain neutral buoyancy while submerged. Low-density solids that may be considered for this purpose include polyethylene, polypropylene, expanded plastics, inorganic foams, and syntactic foam. The foamed plastics and inorganic foams have low strength and high water permeability The low-density plastics have limited buoyancy as well as other problems. Syntactic foams consisting of extremely small and hollow glass, ceramic, or rigid (329. plastic spheres embedded in a plastic matrix have been effectively used at weight of 36-441b/ft(sea water is 641b/ft, 1 Ib/ft=0. 45kg/0.028m), which will with stand pressures at 10000-ft(3048m)submergence with less than 1% water absorption. Its cost per pound of net buoyancy is high, but low compared to that of a pressure hull of titanium or a rigid pressure vessel of higher-strength steel Power a source of power, the lead-acid storage battery, in use in submarines since the beginning century, continues to be most widely employed. It places severe limitations on small ubmersibles because of its relatively high weight-to-energy ratio. However, its characteristics are well known. It is relatively inexpensive, rugged, and reliable, can be quickly recharged, and has a high cell voltage. These batteries are normally carried internal to the hull, either pressurized in oilLesson Twenty-three Oceanographic Submersibles Oceanographic submersibles are small research vessels for underwater transport of people and equipment and for use as underwater platforms for observation, sampling, measurement, and performing various work tasks. They are also referred to as undersea vehicles. There are about 100 crewed submersibles available for use around the world. Of these, about 30 submersibles are available in the United States, the leading country in their development and construction. The highest concentration of submersibles is in support of the offshore oil industry, mainly in the North Sea. The leading mission applications are inspection of pipeline and cables, followed by cable burial, salvage, coral harvesting, geology, fisheries, biology, and environmental research. Design considerations Undersea vehicles are being utilized more now that experience has confirmed their utility, and systems are being designed in accordance with user requirements. A major trend pertains to designing a completely integrated system, which, in addition to the submersible, includes support ship, handling gear for launch and retrieval, and logistic and maintenance support. The (.328.) objective is to obtain an effective, high utilization rate under varying weather conditions. The major vehicle operating problem is handling during launch and retrieval in heavy seas. Equipment for conducting efficient deep-water surveys will systems. Manipulators with greater dexterity will be needed for human-occupied and unoccupied systems to perform intricate manipulative operations more quickly. Many new vehicles are being developed with large panoramic plexiglass windows to provide a wider viewing field, very effective in survey and inspection mission. The ratio of the weight of structure to the sea-water weight for an equal volume determines of a submerged vehicle. This ratio is dependent on several items, one of the most important of which is the compressive strength-to-density ratio of the pressure hull material. Steel with a yield strength of 100000 psi (689500000N/m2 ) is generally employed in vehicles. Hull buoyancy Most small submersibles need buoyancy in excess of that produced by their pressure hulls to attain neutral buoyancy while submerged. Low-density solids that may be considered for this purpose include polyethylene, polypropylene, expanded plastics, inorganic foams, and syntactic foam. The foamed plastics and inorganic foams have low strength and high water permeability. The low-density plastics have limited buoyancy as well as other problems. Syntactic foams consisting of extremely small and hollow glass, ceramic, or rigid (.329.) plastic spheres embedded in a plastic matrix have been effectively used at weight of 36—44lb/ft3 (sea water is 64lb/ft3 ;1 lb/ft3=0.45kg/0.028m3 ), which will with stand pressures at 10000 –ft(3048m) submergence with less than 1% water absorption. Its cost per pound of net buoyancy is high, but low compared to that of a pressure hull of titanium or a rigid pressure vessel of higher-strength steel. Power As a source of power, the lead-acid storage battery, in use in submarines since the beginning of this century, continues to be most widely employed. It places severe limitations on small submersibles because of its relatively high weight-to-energy ratio. However, its characteristics are well known. It is relatively inexpensive, rugged, and reliable, can be quickly recharged, and has a high cell voltage. These batteries are normally carried internal to the hull, either pressurized in oil