Posts Tagged ‘Vacuum infusion’

The following is courtesy of Maritime Propulsion.

Warship Composite Construction – Java Shows the Way

By George Backwell at September 08, 2012 07:22
One of the most innovative warships in the world was launched recently, from remote, tropical Banyuwangi on the sea coast of Java, Indonesia, where North Sea Boats has a shipyard. The high-speed littoral waters patrol boat –  to be named KRI Klewang – has a wave-piercing trimaran hull form (offering a very stable weapons platform) constructed exclusively of infused vinylester carbon-fibre composite.

This composite medium was chosen for its multiple benefits including: reduced weight (laminated carbon fibre has a density nearly half that of aluminium alloys) and reduced maintenance (carbon composites cannot corrode and exhibit extremely high fatigue limits). If that were not sufficient justification, this material also provides the nil magnetic signature, reduced thermal and acoustic signatures required to suit the role of this warship.
This fairly remote area of Indonesia lacked the highly skilled specialist workforce with experience in building composite hulls for such an advanced, relatively large vessel – LOA 63m (206.7 ft)  –  in order to achieve the quality required for a build under the eye of classification society Germanischer Lloyd. To overcome this, North Sea Boats introduced its high volume vacuum infusion system to give the necessary confidence in the quality and consistency of the building work.
The flat, faceted panel geometry of the ship itself (the design provides external ‘Stealth’ geometry) also lent itself to this high volume production system, which also employed numerically controlled milling machine technology for the utmost accuracy.
The builders claim that the use of carbon foam sandwich composites on this scale in naval application is unprecedented outside of Scandinavia and is representative of the current state of the art in both maritime composites structural engineering and production technology.
Accommodation is provided for a complement of twenty nine (officers and crew) on three internal decks (including bridge and combat control centre), with facilities and equipment for deployment of special forces troops, including an 11m high speed 50 knot RIB, also manufactured and supplied by North Sea Boats.

Propulsion System

Power comes from multiple MAN Diesel & Turbo V12 diesel engines, coupled to MJP 550 propulsion water jet units which are located in both the centre hull and each of the two side hulls for maximum propulsive thrust and manoeuvrability.

Marine Diesel Engine MAN V12-1550: Image courtesy of MAN

The  MAN 4-stroke power plants each have 12 cylinders in 90° V configuration with four valves per cylinder, water-cooled, plus two- stage exhaust gas turbo-chargers. These engines have common rail electronically controlled direct fuel injection.

The stainless steel water jets, manufacture certified by DNV, come from MPJ Waterjets, part of the Swedish industrial group Österby Marine.

KRI Klewang – General Specifications

LOA 63.0 m (206.7 ft)
Length on Waterline 61.0 m (200.1 ft)
Beam Overall 16.0 m (52.5 ft)
Water Draft 1.2 m (3.9 ft)
Sprint Speed 30+ kts
Range 2000+ nm
Fuel Capacity 50,000 ltrs (13,208 US Galls.)


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