So Near yet Sonar for Navy Minehunters

28 March 2011 (Last Updated March 28th, 2011 18:30)

Recent contract activity has reaffirmed the seriousness of the threat mines pose to navies worldwide. We take a look at some of the recent contracts awarded to establish the current trends aboard mine countermeasure vessels.

So Near yet Sonar for Navy Minehunters

A spate of recent construction and upgrade contracts for mine countermeasure vehicles (MCV) issued in recent months has added new impetus to the debate over the seriousness of the sea-based mine threat in modern naval warfare.

Technological advances in land-based mine countermeasure vehicles, such as the HMMWV Laser Ordnance Neutralisation System (HLONS), have proved sufficiently adequate in negating the threat posed to infantry, but such a system is currently not in existence for use at sea.

The seriousness of the mine threat is debatable, but recent reports suggest that the danger of naval mines is ever present. A Russian probe into the sinking of the South Korean warship Cheonan, which sparked a major international incident amid fears of North Korean aggression, was actually the fault of a sea mine.

Unconfirmed reports from North Korean defectors appeared in December 2010, alleging the development of nuclear mines using nuclear warheads while a number of autonomous underwater vehicles (AUV) are now being used to counter these threats. Most recently, the governments of Serbia and Croatia pledged to cooperate on mine clearing projects including a minefield near Djerdap gorge, Serbia, the scene of sunken fleet of German ships carrying naval mines.

In response, the latest fleet of MCVs and upgrades to existing vessels have improved sonar capabilities, shock resistance and communication infrastructure, whilst also adopting pupose-built propulsion systems to avoid accidental detonation.

"The Finnish navy has moved to strengthen its mine countermeasure capabilities."

Existing purpose for new ships

The Finnish navy has moved to strengthen its mine countermeasure capabilities with the addition of three new MCV 2010 class vessels, labelled as the Katanpää class. They are due to replace the Kuha class minesweepers that were constructed through 1974-1975 and further modernised in the late 1990s.

The fleet of three Katanpää class vessels make use of a fibreglass hull that utilises vacuum infusion techniques during the construction of its superstructures. This increases the mechanical properties of the hull whilst also resulting in a better product quality and eliminates the risk of noxious emissions.

The hull, decks and bulkheads are made of fibreglass additionally reinforced with balsa and carbon fibre, designed to rapidly improve the ship's shock resistance against underwater explosions as well as magnetic, noise and pressure signatures that could cause mines to detonate. For the same reason, all three vessels are powered by diesel-electric powertrains and Voith Schneider propellers.

The first vessel, named Katanpää, was initially launched on 16 June 2009 and will begin its sea trials in March 2011 before being delivered to the Finnish navy upon trial completion. The second vessel will follow before the year's end, with the third being delivered in 2012.

The vessels mark a significant investment in Finland's multipurpose mine countermeasure vessel capabilities, with the vessels costing a combined €244.8m although they are expected to remain in service till 2040-2042.

New equipment, not new vessels

The UK has decided to refit existing ships rather than enforce their minehunting capability with new vessels. In November 2010, Babcock successfully completed the refit of HMS Blyth, a Sandown class single role minehunter, on time and on budget.

The refit included a number of upgrades, a substantial maintenance package and two first-of-class equipment fits that occurred during the six month Support Period Docking. As a result, HMS Blyth became the first single role minehuner to receive the Defence Information Infrastructure (Future) (DII(F)), which enables the vessel to share information and work collaboratively across the defence sector network. She is also the first to receive remote isolation capability fitted to the ship's wastewater system.

The refit has helped the vessel achieve higher speeds with increased fuel efficiency as a result of a new polymer-based foul release paint system, while preservation of superstructure areas and internal deck coverings was undertaken. Living quarters were improved, and the starboard Voith Schneider propeller unit was exchanged.

Under the refit, a total of 375 items of equipment were overhauled or replaced in order to ensure that the UK's mine countermeasure fleet can retain its readiness.

Hunt Class to receive boost

On top of upgrades to the Sandown class minehunter vessels, Hunt class mine countermeasure ships are set to receive refits as of this year. Of the 13 Hunt class vessels that were commissioned between 1980 and 1989, eight remain in service and are currently undergoing extensive upgrades.

"The upgrade approach chosen by the UK is similar to that adopted by the US."

Northrop Grumman recently received a contract from BAE for the upgrade of machinery control, alarm and surveillance (MCAS) systems aboard all eight remaining vessels, which will see Northrop's Sperry Marine business supply new-generation systems to replace the ships' aging, existing MCAS.

The new system monitors in excess of 500 sensor points across the main propulsion engines and drive systems, generators and auxiliary machinery.

Installation, testing and commissioning is expected to take place between 2011 and 2015 following the completion and validation of the design, and Northrop Grumman chairman Sir Nigel Essenhigh believes these mission-critical upgrades to be of importance to the UK Royal Navy, adding, "These ships play an important role in enabling the Royal Navy to carry out its operational commitments, which includes protecting valuable shipping lanes."

Sonar upgrades

The upgrade approach chosen by the UK is similar to that adopted by the US, as noted by the December 2010 award of a $14m contract to BAE systems for the production of improved sonar detection systems.

A total of four upgraded AN/SQQ-32(V)4 sonar sets, designed by Naval Surface Warfare Center Panama City and Applied Research Laboratory of University of Texas, US, have been ordered in order to replace the current AN/SQQ-32(V)3 system that operates aboard the MCM-1 Avenger class minehunter vessels.

The upgrades are designed to improve detection performance in littoral environments and whilst operating against stealth mines through the use of high frequency, wide-band technology.