Basic facts KNM Skjold
L o a: 46,9 m
Beam: 13,5 m
High: 15 m (On cushion)
Draft: 2,3 m (Off cushion)
Speed: In excess of 55 knots
Displacement: 260 tons
Main engines:
2 gas turbines Rolls Royce Allison 571 KF 6000 kW (2 x 8160 Hp)
Auxillary systems:
2 Auxillary engines: MTU 6R 183 TE52 275 kW
2 Lift fan engines: MTU 12V TE92 735 kW
2 Manoeuvering engines: MTU 6R TE 92 370 kW
Generator:
440V 60Hz 3 phase 4 polar 228 kW
Propulsion:
2 x 80 cm KaMeWa water jets
Main gun:
76mm Oto Melara Super Rapid
Missiles:
Kongsberg NSM - Kongsberg Nye SjømålsMissiler (=New anti
shipping missiles) developed for Skjold-class MTB.
Weapon control:
Delivered by DCNi.
Bridge consoles/
navigation equipment:
DCNi with norwegian subcontractors has delivered a bridge which
is based on a proven concept already in use on several fast
ferries.
The brigde is
equipped with all modern electronic navigational equipment.
A SES is in principle based on a catamaran hull where lift fans blow air into an air cushion between the hulls. Rubber finger type seals in the bow and a bag seal in the stern close the air-leakage. An air pressure equivalent to abt. 0.5m water column is maintained and controlled by a Ride Control System.
The RNoN has acquired a substantial experience with naval SES during the last 5 years. The unique features of the SES concept as verified by the Oksøy class SES MCMVs are
In addition the FPB will utilise the extreme low resistance offered by the SES. The wetted surface of the side hulls is significantly reduced compared to catamarans. The wave resistance caused by the air-cushion is heavily speed dependent and vanishes at high speed, resulting in low high speed resistance compared to any displacement or semi-displacement vessels.
An important advantage is the low draft of the SES when operating on-cushion. A draft of less than one meter offers significant advantages in shallow waters, i.e. reduced likelihood of grounding and less vulnerability due to less exposed area for impact of floating objects.
The twin hulls have important advantages regarding survivability and redundancy. All important systems are redundant, and the vessels can operate with one engine room set out of work.
Machine Control Room where all ship tecnical equipment can be
controlled. All engines may also be controlled from the bridge.
A combination of global and local FEM calculations have been carried out extensively, considering the anisotropy of the sandwich structure where needed. The theoretical laminate properties are based on the Tsai-Wu failure criterion, which have been verified by extensive laminate testing performed by the yard. The hull materials are selected following detailed assessment of mechanical properties and producibility. Special attention to waterjet interface with adjacent structure and mast were paid. Stiffness requirements to secure sufficient stiffness to the structures which are supporting the gun and EO/K-band radar director required extensive analyses.
All structures are built with FRP sandwich using uni-axial glassfibre and carbon laminates with vinylester or polyester resin. PVC core material is used in main structural elements below main deck and PMI core material is used elsewhere and for the complete superstructure.
The advantages with such a sandwich structures are multiple:
A large quantity of the internal structural elements, internal and external decks, beams and the complete superstructure with the carbon fibre mast were fabricated applying the closed SCRIMP process, which is a vacuum assisted resin injection method used in order to reduce the styrene emission, to reduce the structural weight and improve the laminate properties. Heated walking zones on the upper deck to avoid ice build up is installed.
The extensive use of carbon is used in structures with high stiffness requirements, as beams, the mast and the supporting structure for the gun and EO/radar director.
For the first time
radar absorbing materials are included in the loadbearing
structure (structural RAM) of a vessel over large areas. This
contributes to significant weight reduction compared to the
conventional method of cladding this material on the outside of
the load bearing structure. The ship is designed with a low
number of reflective panel orientations and none right angled
corners. This is the reason for the faceted external shape of the
vessel.
Much effort is applied to minimise secondary structure and outfitting penetrating the flush exterior of the vessel to minimise the contribution to the radar cross section. All exterior doors and hatches are made flush and have exactly the same radar reflecting/absorbing characteristics as the adjacent panels elimination the reduction of the signature properties. Necessary deck outfitting as mooring pullers are either covered with radar absorbing covers or made de-mountable (rails). Window screens are made radar reflective and are installed flush without any visible coaming.
The Skjold class is designed with low IR and optical signature. A painting system with high IR absorption properties and a colour pattern to reduce optical signature measured for typical Norwegian coastal waters contributes to a balanced low level of signatures.
Artist impression of the anti shipping missile.
We have made a video (1,1Mb) from the testfiring of the 76mm Oto Melara
in 45 knots.
Below you can study some shots from the video.
