Fridtjof Nansen (F85) class Project 6088 New Frigate - Design
The vessel is an antisubmarine frigate primarily designed to detect, identify, engage and attack hostile submarines, also provided with anti-air, anti-surface and electronic warfare capabilities, offering significant potential for non combat tasks in peace time, such us to conduct sovereignty tasks. The platform design has been established to accommodate the Combat System dimensional fit, which represents the envelope of the complete set of sensors, weapons and C3I elements required to fully satisfy the requirements stated by the Royal Norwegian Navy.
The hull lines, based on the results of the BAZAN┤s own hydrodynamic research programs, have proven excellent stability, seakeeping and manoeuvrability. Hull appendages and propellers were designed for low hydrodynamic noise, based on F-100 frigate experience.
The project is a five deck concept ship, subdivided in thirteen watertight compartments and two superstructure blocks above the level 01, being both, ship┤s hull and superstructure, of welded steel using hybrid structural concept, where a mix of commercial and naval practices are applied.
The propulsion plant is a CODLAG cross connected type, having one gas turbine of 22200 kW, two AC propulsion electric motors of 2500 kW each, one gears set and two shaftlines each one driving a fixed pitch propeller. The ship has two Main Engine Rooms, separated by a Central Auxiliary Machinery Room. Additionally, an Aft Diesel Generator Sets Room is located astern the Aft Main Engine Room.
The gas turbine is installed in the Forward Main Engine Room. The gears set, installed in the Central Auxiliary Machinery Room, consists of a cross connecting primary gear and two secondary gears, linked by elastic couplings, being each secondary gear fitted with a clutch and a thrust bearing. Finally, the propulsion electric motors, located in Aft Main Engine Room, are mounted directly on the propeller shafts. The motor speed control is carried out by frequency converters.
In the quiet sailing mode, up to 16 knots, the gas turbine and the gears set are disconnected, being the propulsion electric motors capable of driving the ship ahead up to the cruise speed. For boost propulsion, the gas turbine and the propulsion electric motors run together.
A retractable bow thruster for improving the ship manoeuvrability in confined areas has been provided. This equipment can be used as an auxiliary propulsion unit in case of emergency, when the main propulsion is damaged.
The Engine Rooms are unmanned according with the DNV rules. During normal working conditions, the propulsion plant was remotely operated via the Integrated Platform Management System (IPMS) from the Engine Control Room (ECR) or from the Bridge. Local control would also be possible from the machinery spaces. An alternative CODAG propulsion plant was also offered based in a gas turbine and two diesel propulsion engines driving two controllable pitch propellers.
The electrical plant is capable of supplying the electric power required by the propulsion electric motors and all ship auxiliaries. The generators would supply electric power at 690 V, 60 Hz, 3 phases to two Main Switchboards, that supply power to the propulsion electric motors, specific ship auxiliaries and the Ship Service Distribution Main Switchboards through two 690/450 V transformers.
The electrical generating plant was composed of four main diesel generator sets, two of 3000 kW and other two of 1100 kW. Two main diesel generator sets, one of each size, are located in the Forward Main Engine Room and the other two are arranged in the Aft Diesel Generator Sets Room. These rooms are separated by two watertight compartments and one damage control zone.
Two Main Switchboards (MSB) of 690 V and two Ship Service Distribution Main Switchboards (SSMSB) of 450 V are located on the second deck, being arranged one of each type in the same main watertight compartment than the Forward Engine Room and the Aft Diesel Generator Sets Room. Each 690/450V transformer, 2000 KVA size, was able to supply the required power to all ship service loads with the other one as stand by. Main Switchboards (690 V and 450 V) are interconnected in a ring configuration. The propulsion electric motors were fed from both Main Switchboards (690 V) and the ship vital loads would receive double power supply from the Main Ship Service Switchboards (450 V). The plant incorporated facilities for automatic starting and synchronisation and parallel connection of the main generators. The plant can work in parallel or split modes.
The BAZAN┤s project, has been designed with the objective of achieving a high degree of survivability. Survivability was defined as being a combination of two basic elements, which are the susceptibility and the vulnerability.
Susceptibility was the likelihood of being hit and was associated with the ship stealthiness, i.e. with a controlled signature management plan and with its own self-defence capability. Signature reduction measures are useful to decrease the chance of being detected and classified. A carefully design of the top side and the underwater hull, as well as the implementation of special devices, as acoustically hooded equipment, resilient mounting equipment, flexible elements in the noisy flanking paths, infra-red suppression system, prewetting system, degaussing system, active shaft grounding equipment etc, lead to minimise the underwater acoustic signature, to reduce the radar cross section and to offer an small infra red signature and an low magnetic signature.
Vulnerability was the resistance to damage and was associated with hardening, system separation, redundancy, damage prevention and damage control management. The following features minimise the vulnerability, assuring the highest probability of survival during combat : shock resistant, ballistic protection of main operational rooms, four damage control stations, Neuclear Biological Warfare defence, mobility with two compartment flooded, electric power supply ensured with three compartment flooded, two shaft lines, retractable emergency propulsion unit, casualty power supply system, etc.
A baseline Integrated Weapon System was offered based on rotating radar acting BAeSEMA as IWS Subcontractor. Anti Air Warfare sensors consist of a three dimentional rotating radar with electronic stabilisation and a long range two dimentional radar, providing good performances in detection of sea skimming missiles. Two combined radar and electro-optical trackers fitted with Continuos Wave Illuminator provide Evolved Sea Sparrow Missiles guidance, for long and medium range anti air defence as well as gun fire control. Short range anti air defence was covered by infrared guided missile-based Close-In Weapon System. Passive air and surface surveillance was provided by a two band Infrared Search and Tracking System.
An alternative Integrated Weapon System was also offered based on Lockheed Martin's AEGIS Combat System, designed around the multifunction phased array radar Spy-1F, that provides simultaneous missile and gun fire control tracking of several targets while volume and horizon search and track of additional targets. Its instantaneous beam steering minimises also reaction time against any air threats. Two Slave Illuminators provide final guidance for the Evolved Sea Sparrow Missile. Passive target tracking was provided trough the electro-optical and infrared tracker.
Both options include a Hull Mounted and an Active Towed Array sonars. They provide the ship with short, medium and long range antisubmarine detection. Antisubmarine target engagement was accomplished with Ship or Helicopter Launched Torpedoes, and depth charges. The anti submarine warfare was prepared to incorporate Ship Surface Torpedo Defence system and sonobuoys.
Anti aircraft defence surveillance capabilities are completed in both options by the incorporation of an Electronic warfare suite, comprising electronic support measure systems in the radar and communication bands.
Likewise, IWS includes two modules of four Launchers for the Norway's New Anti-ship Missile under development. Evolved Sea Sparrow Missiles are launched from an eight cell Vertical Launching System, with the capability of up to 32 missiles (4 per cell). Torpedoes are launched from two twin magazine torpedo launchers. Electronic warfare included two off-board active decoy launchers as well as two trainable chaff/infra red launchers.
Finally ship's internal and external communication systems are managed by an Integrated Communications Control System.
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