Construction Of Two RAN Minehunters Progressing At Carrington Slipways
Earlier this year, after intensive design investigation and development, the Commonwealth of Australia Department of Defense placed a contract with Carrington Slipways Pty Ltd. for the construction of two prototype catamaran minehunters for the Royal Australian Navy. Each is 31 meters in length, 9 meters abeam, displaces 170 tons and has a speed of approximately 10 knots.
The catamaran design for a minehunter allows a unique combination of proven concepts to be used which include: (1) A catamaran hull form which provides a large stable working area, reduces pressure signature and allows machinery to be placed high in the ship to reduce magnetic and acoustic signatures, minimizing the risk of mine activation. (2) Foam sandwich construction which further reduces the noise signature, provides good thermal insulation, requires a minimum of maintenance and provides improved shock resistance. (3) Use of twin diesel engines of a single type, each simultaneously driving a generator for ship power and a hydraulic pump for transmission of power to the propulsion steering units, all mounted well above the water line. (4) A containerized weapons control system which utilizes the functions of the navigational sensors, the sonar and the precision navigation equipment to control a recoverable submersible mine disposal vehicle. The vessels are being built in a special purpose facility. The storage areas for GRP materials and the construction areas are environmentally controlled within strict limits to provide optimum conditions for applications and curing.
The hull core is made up of high density PVC foam which is glued together on a male mold. The outer skin is then laminated and the shell turned and put into a cradle for lamination of the inner skin and installation of internal bulkheads, decks and other substructure.
The main deck core is laid up on a concave mold and the concave side of the foam laminated. The mold with the deck attached is then lifted, inverted, placed in position over the hull structure and secured. The deck mold is then removed and the upper side of the deck laminated and overlaid to the sides. The whole hull is then rotated through 180° to allow the lamination of the underside of both No. 1 and No. 2 decks. On completion of this operation the hull is turned again to the upright position.
The superstructure is assembled separately in the component area and installed as a unit following construction of the hull and upper deck.
GRP and foam sandwich components for construction and outfitting are manufactured in the component fabrication area. The hull is constructed in a 4-meter-deep construction dock which is fitted with lifting platform and turning mechanism to ensure that the hull can be lifted and rotated as necessary to achieve the best attitude for laminating activities.
A comprehensive quality program to the standard of AS1822 is utilized to ensure that the strict requirements for structural strength reproducibility and magnetic cleanliness are met.
The weapons containers, designed as part of the weapon system by Krupp Atlas Electronik, are also manufactured from foam sandwich in the facility using the same standards as are applied to the Minehunter.