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Article "American Progress"
"AMERICAN PROGRESS"
Delivered in September this year, American Progress is the first USA-built tanker to meet the requirements of the Oil Pollution Act of 1990. Her delivery also marks another step by USA shipbuilders on their path back to commercial ship construction, side-lined for so many years as the world's most powerful naval fleet was created.
Built by Newport News Shipbuilding in Virgima, American Progress is adouble -hulled, single-screw petroleum products tanker, with a total capacity of about 340 000 barrels. She is part of Mobil Oil Corporation's continuing philosophy to operate a fleet of state-of-the-art vessels which meet or exceed USA and international safety and en-vironmental standards. The ship is the third double-hull tanker to enter service for the company. Two VLCCs Raven and Eagle are currently operating, with two further similar vessels on order.
Mobil says that as a leading oil. natural gas and petrochemical company, operating in more than 125 countries, safe-ty and protection of the marine environment is a top priority and the double-hull technology of the vessel is only part of the equation. Trained crews and a sound management structure supported by good maintenance programmes are all elements in achieving this aim.
The vessel will operate under the US flag and be primarily used to carry gasoline and distillates between Mobil's Beaumont, Texas refinery and markets in Florida. She has replaced Mobil's Seminole on the route.
The market being served is large and the vessel is expected to make about 40 voyages annually delivering more than 14 mill barrels, representing about 10% of the state'.s consumption.
The vessel was built using the Alternate Compliance Program (ACP) under which the USCG accepts international standards for materials and equipment in lieu of equivalent US standards, and has benefited by the US government's pledge of regulatory reform.
The ship was designed using the ABS 'SafeHull' and Dynamic Load Analysis programs and carries the following no-tations: Al E "Oil Carrier", +AMS, +ACCU, SH, DLA, IGS, COW.
Cargo is carried in seven pairs of main cargo tanks and two slop tanks which are divided by a centre line bulkhead. The double hull is formed by five sets of port and starboard T wing ballast tanks and the centreline bottom stool void space. Forepeak and afterpeak tanks provide additional ballast capacity. The hull is constructed almost exclusively of mild steel, with exceptions of the lower stool upper transverse floor frames, which are DH32 high tensile steel with a thickness of 25 mm.
Cargo systems
The vessel can carry three grades of cargo simultaneously, each segregated by a double-valve arrangement. Cargo transfer is facilitated by three Shinko steam turbine centrifugal pumps, each fitted with a 'prim-a-vac' priming sys-tem. The pumps are each rated at 1400 mVh at 125 m head. To maximise cargo out turn, suction wells are fitted in all cargo tanks and stripping suctions are provided off the main suction lines. The vertical gear stripping pump, of Houttin manufacture, is driven by a Shinko steam turbine. All valves are hydraulically operated, either remotely from the cargo control room or locally on deck. The hydraulic valve system has been supplied by MacGregor Liquid Cargo Group. The system is of the intrinsically safe deck box design with multi-tube stainless steel tubing used to supply individual valves. The hydraulic supply for individual cargo valves is run through the lower centreline stool access, thus ininimismg piping runs in the actual tanks.
The cargo tanks are all fully coated with Amercoat 90HS two-coat pure epoxy system from Ameron Coatings.
The cargo level monitoring system has been supplied by Skarpenord and displays in the cargo control room show Lank level, cargo density, temperature, and tank pressure. Skarpenord has also supplied the loading computer which has on-line input of cargo information to track hull stresses as the cargo
The tanks are protected by an inert gas system supplied by Perinea Maritime Protection which can be operated from the boiler flue gas or from an MDO gas generator. The generator has a capacity of 5250 m3/h and two sets of blow-ers each with a capacity of 6330 m3/h. The fixed tank washing system is manufactured by Toftejorg and comprises 46 single-nozzle units. Each of the units is programmable and have throughput of 37 m3/h at 8 bar
Machinery
Main propulsion is supplied by a single MAN B&W 6L60MC Mk5 slow-speed diesel built by Kawasaki in Japan, and driving a Nakashima four-bladed Ni-AI-Bronze, 6.6 m diameter propeller. At normal continuous rating (ncr) the engine produces 9180 bhp, increasing to 10 800 bhp at ncr. On trials the vessel achieved 14.5 knots on 11.5 m draught at mcr. ( Maimum continuous rating ).
Steering gear of the double-acting electro-hydraulic, unitised rotary vane type was supplied by Porsgrunn;
Auxiliary power generation is provided by three Daihatsu dicsels, one rated at 1250 hp at 900 rpm and two delivering 900 hp at 900 rpm. These are each close-coupled to dedicated generator ends producing 850 kW and 600 kWre-spectively at 450V 60Hz three-phase. In addition a MAN DEMP D2866 TE diesel coupled to a Stamford generator producing 170 kW at 1800 rpm is supplied for emergency use. Other power output is supplied by three Aalborg Sun-rod boilers rated at 30, 10 and 3 t
i capacity respectively. All the main and auxiliary engines are designed to run on 700 cSl fuel which has been through a purification system supplied by Westfalia. The machinery monitoring and main engine control system is manu-factured by Norcontrol. Ancillary machinery includes an Alfa Laval fresh water JWSP-26-C 100 generator; Detegasa bilge water separator; Kay Lindegaard SH 20-SM incinerator; Hamworthy ST/2A sewage treatment plant : Navalimplanti Sinlesi 3000/2-30L oil discharge monitor and control system. The vessel's navigation and ship opera-tions equipment features the latesttechnology. There is a fully-GMDSS compliant communications installation utili-sing both Inmarsat-B and -C systems; two ARPA radars which are interfaced with a Sperrv electronic chart display. This is directly connected to the ship's gyro and DGPS, with back-up information available through an additional GPS and Loran receivers. Engine manoeuvring and monitoring of all critical shipboard systems can be undertaken from the bridge.
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