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Vessel: Zirfaea Yard: Bodewes Volharding Delivery: 1993

Designed and built for the Dutch Ministry of Transport, Public Works and Water Management, North Sea Directorate, by Bodewes Volharding of Groningen, The Netherlands, the Zirfaea's main task is as a hydrographic surveying and research vessel, working on the North Sea and the Dutch part of the Continental Shelf. Designed by Nevesbu of The Hague, the Zirfaea incorporates a wide range of the latest in hydrographic instrumentation.

Survey and research ships differ in design from other small vessels based on their tasks, layout and, in the Zirfaea's case, special requirements for working in areas like the North Sea. Specifically the vessel features: acoustic standards of high level in machinery, hull and working/ living areas; adequate room for I The launch of the Halter Marine-built USNS Sumner. 58 expansion; low operating costs to allow future vessel replacement; a good stability range for all operations, including the handling of relatively heavy equipment over both sides; good course stability at very low speeds; good maneuverability; roll suppression; and large open deck space. The Zirfaea is fitted out with a three-tier superstructure consisting of a bridge deck, a state deck and a forecastle deck which runs continuously from the stem to the working deck amidships aft. The wheelhouse/ survey room on the bridge deck has a 360-degree view; the state deck below the bridge deck features a spacious director's room for meetings; the forecastle deck is used mainly as living quarters. A diesel-electric main propulsion plant — consisting of four generator sets, each of them comprising a Mitsubishi type S6RMPTA marine diesel engine coupled to an Indar generator—power iheZirfaea. Two Indar electromotors are coupled to two Lips steerable Azimuth thrusters (five-blade). A Valmet diesel, type 620D, 90 kW, 1,500 rpm driving an Indar generator, type LCB-250- M/4, serves as the emergency generator. The deck equipment gets its power from a central hydraulic powerpack system via a hydraulic power ring. The powerpack comprises a storage tank, two 22-kW feed pumps and two 160-kW main pump sets. The 220cc open systemtype pumps have a constant hydraulic pressure control system, designed so that one main pump set in conjunction with one feed pump delivers enough power for all normal working conditions.

In order to execute its diversity of operations, the vessel is equipped with a wide range of special instruments, systems and facilities, including: Simrad ADP-701 dynamic positioning system; a 12.5-ft. by 12.5- ft. (3.8-m by 3.8-m) moonpool; Eekels closed-circuit television; Theunissen open-loop intercom; and (two) Datawell Hippy-120C MK II heave compensators.

Vessel: USNS Sumner Yard: Halter Marine, Inc. (Trinity subsidiary) Delivery: May 1995 Trinity Marine Group subsidiary Halter Marine, Inc., located in Moss Point, Miss., recently launched TAGS 61, dubbed USNSSurrcrcer. The vessel is the second of three T-AGS 60 class multi-purpose oceanographic survey ships under construction at Halter Marine for the U.S. Navy.

Sumner was preceded by T-AGS 60, USNS Pathfinder, which will be delivered in October 1994, and will be followed by T-AGS 62, USNS Bowditch, which is scheduled for delivery in November 1995.

Sumner, which measures 329 ft. (100.3 m) long, with a 58-ft. (17.7-m) beam and a 19-ft. (5.8-m) draft at full load, is designed with a a common bus diesel electric propulsion system consisting of twin screw propeller drives through Z-drives. The Z-drives include gear reduction and 360-degree thrust direction control in a compact unit. Elimination of conventional reduction gears and long propeller shafts free space to be used for oceanographic purposes.

Sumner features complete thrust direction control, which provides excellent ship control and maneuverability, enabling precise position keeping and track following. A pair of 2,435-kW and a pair of 1,825-kW diesel generators are integrated to provide power to the propulsion system, ships service and laboratories through a power conditioner. Propulsion power is from two General Electric 4,000-hp DC motors, enabling the vessel to sustain a 16-knot speed.

Incorporating a full array of the latest electronics and oceanographic equipment, theSumner will be able to measure water depth over an area as great as 12 miles wide in the deep ocean; continuously determine its position to within 50 ft. (15.3 m), at any time in any weather condition; and measure oceanic acoustic qualities. A typical mission might include oceanographic sampling and data collection of surface, midwater and ocean floor areas; launch and recovery of scientific packages including ROVs; and shipboard oceanographic data processing and analysis. The Sumner will be operated for the Oceanographer of the Navy by the Military Sealift Com- - mand. Mission scientists and technicians will come from the Naval 3 Oceanographic Office in Bay St. Louis, Mo.

Trinity Marine Group posseses 3 vast experience in the building of oceanographic vessels, having built 3 T-AGOS 13 through 18 (oceanos graphic surveillance ships); T-AGS 1 51 and 52 (hydrographic survey 3 ships); and AGOR-23 and AGOR-24 r (both are oceanographic ships; AGOR-24 is now under construc- ;. tion at Halter Marine).

) The T-AGS 60 class of ships are t designed and built to provide multipurpose oceanographic capabilities i in coastal and deep ocean areas, and are U.S. Coast Guard-certified and e ABS-classed. The class boasts 3,500- i sq.-ft. of working deck, and is 1 equipped with three multi-purpose f cranes (Allied Marine telescoping i boom crane; Hiab foldable boom e crane; Appleton towing crane); one articulated davit, both side and stern t U-Frames (from Fritz Culver); and five winches (from Dynacon).

 
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