An Cosantóir

An Cosantóir September / October 2024 www.military.ie/magazine 34 | FROM THE ARCHIVES An Cosantóir Volume 74, Issue 07, Sep 2014 An Cosantóir September 2014 www.dfmagazine.ie 14 | by LT CDR TONy O'LEARy PhotoS by CPL NEVILLE COUGhLAN & A/SEAMAN DAVID JONES T he Naval Service, as the maritime element of the Defence Forces, is the state's principle sea-going agency. As an island nation, 99% of our trade is transported by sea. to exercise and uphold the state's sovereignty and obligations, the Naval Service patrols Ireland's 220 million maritime acres, an area 12 times larger than the island of Ireland. Due to the age profile of the current fleet (six of the eight vessels are over 30 years old) and to fulfil the roles assigned by government, approval was given in 2007 to initiate a tender com- petition to purchase two new off-shore patrol vessels (OPVs), with an option to purchase a third such vessel (government recently confirmed that this option will be exercised). Following this decision, a new vessel project team comprised of subject matter experts from all branches of the Naval Service was established. After developing a detailed concept-of-operations for the vessel, a comprehensive specification running to some 400 pages, was written and issued to prospective candidates as part of the invitation-to-tender process. This process culminated in 2010 with the signing of a contract with Babcock Marine for the provision of two 90m OPVs. The vessels were to be built in Appledore Shipyard in Devon to a proven hull design produced by STX Marine (Canada). The new OPVs, although similar in appear- ance to LÉ Roisín, will feature a number of substantial improve- ments to the tried and tested long-range patrol vessel (LPV) class used by the Naval Service since 1999. Following an in-depth analysis of prevailing and predicted weather patterns in the Naval Service's area of operations it was decided to lengthen the vessels by approximately 10m to an over- all length of 90m and increase displacement to approximately 2,000 tonnes. This will improve overall operational effectiveness, efficiency, durability and overall crew comfort. The new vessels are to be longitudinally framed rather than the transverse framing used in the previous class. This will have the effect of strengthening the vessels and making them more resistant to the structural damage associated with operating in the heavy North Atlantic seas. Another first for the Naval Service is the inclusion of passive roll-reduction tanks in addition to the active fin-stabilisation system fitted to previous vessels. These passively controlled U- shaped tanks will reduce the ships' roll profile at low speed (below 10kts), which will allow for safer launch and recovery of the ships' rigid-hulled inflatable boats (RHIBs). A new propulsion system, allowing for speeds of 23kts, is provided by two medium-speed, Wartsila engines capable of developing 5,400Kw each via reduction gearboxes and two five-bladed, controllable-pitch propellers. The vessels are also capable of low-speed operation (approximately 8kts) through a power take-in electric motor driven from the ships' electrical alternators, and connected to both shaft lines via a dedicated clutching system. This option will improve fuel efficiency, reduce main engine maintenance and enhance the vessels' 'green' pro- file and carbon footprint. Another change is in the introduction of dynamic positioning, a computer-controlled system that will automatically maintain heading or position by utilising the ships' 450Kw Bowthruster main engines and two independently controlled rudders. This sys- tem will greatly assist navigational watch-keepers in operations involving remotely-operated underwater vehicles, and operations involving unmanned aerial vehicles. On the bridge, a completely integrated mission system suite is being added, comprising an integrated navigation bridge system; internal and external communications outfit; and an electro-op- tical surveillance/gunfire control system, which provides control and prediction for the Oto Melara 76mm main armament in the surface- and air-engagement role. Access to engine room moni- toring and alarm system and the ships' extensive CCTV system NEW VESSELS FOR NAVAL SERVICE

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