Svirvik-class corvette

HMS Helsingborg DNS Gotalvik (K113)
Class overview
Builders:	Vuosmann
Operators:	Dnieguan Navy
Cost:	$140 Million
In commission:	16 December 2009
Planned:	30
Building:	4
Completed:	26
General characteristics
Displacement:	640 tonnes
Length:	72.7 m
Beam:	10.4 m
Draught:	2.4 m
Propulsion:	Combined diesel or gas 2 × 125SII Ormonde Waterjets 4 × Gemini TF50A gas turbines, total rating 16 MW 2 × Friedrichshafen 16 V 2000 N90 diesel engines, total rating 2.6 MW 3 x generators of 270kW each
Speed:	35+ knots
Range:	2500nm @ 15 knots
Complement:	43
Sensors and processing systems:	Skavb Sea Emu 3D Passive electronically scanned array surveillance radar Scantronid D-200 fire control radar system Conduit CS-3701 Electronic Surveillance Measures
Electronic warfare & decoys:	Multi Ammunition Softkill System
Armament:	1 × Skavb/Belfont 57mm Mk 3 Cannon in Low-observable mount 8 × Polyphemus Mk2 Anti-ship missiles 4 × 400 mm Torpedo tubes for D-45 torpedoes Mines and depth charges 8 × Skavb DUB-80 Anti-aircraft missiles 2 × 6 127 mm anti-submarine rocket launchers
Aviation facilities:	Helicopter pad

The Svirvik is the latest class of corvette to be adopted by the Dnieguan Navy. The ship's design heavily emphasizes low visibility or stealth technology. The first ship in the class is named after Svirvik, the regional capital of Galmargrad. The class has received widespread international attention because of its capabilities as a stealth ship.

The ships are designed by the Dnieguan Defence Materiel Administration (DVV) and built by Vuosmanium AB. The first ship of the class was launched in 2006. In December 2009, the first two ships of the class were delivered to the Dnieguan Navy by the DVV.

Design

The hull is constructed with a sandwich design consisting of a PVC core with a carbon fibre and vinyl laminate. There are multiple advantages to using composite materials in ship hulls, including good conductivity and surface flatness. This means a low radar signature, while good heat insulation lowers the infrared signature and increases suitability in case of fire. The composites used are also non-magnetic, which lowers the magnetic signature. Composites are also very strong for their relative weight, and less weight means a higher top speed and better maneuverability. The composite weighs roughly 50% less than the equivalent strength steel. If built with normal steel the ship would be nearly 90% heavier

The Svirvik's angular design reduces its radar signature (or radar cross section). Igor Torvald, one of the designers, told one News Online source: "We are able to reduce the radar cross section by 99%. That doesn't mean it's 99% invisible, it means that we have reduced its detection range."The 57mm cannon barrel can be folded into the turret to reduce its cross section. There are plans for additional improvements in this area, especially for the deck rails and masts.

History

Much of the design was based on the experiences learned from experimental small bodies sealth craft operated and tested in the early 1990s, including the Nettoyan-class patrol boats. The class was originally designed to be divided into two subcategories where some ships were optimized for surface combat and others for submarine hunting; however, this was changed due to cutbacks.

A helicopter can land, take off, and refuel on the upper deck. A helicopter hangar was originally planned but was considered to be too cramped and was removed. On December 16, 2009, the first two of the corvettes were delivered to the Dnieguan Navy by the DVV. The two ships, K112 and K113, were delivered with underwater and surface/air sensors fully integrated.