Combat Fleets of the World reports the Roisins at $34 million in US dollars, 30 million Euros should be right on target. Its an offshore patrol vessel with a 76mm gun and small arms without any combat weapons control systems, which could easily double their price. They are built to commerical standards, not to military standards. They have very good range for a 78 meter vessel, capable of fishery protection and EEZ patrols. Since their EEZ is mostly to the west of the island nation, land based helicopters are used, only one of their eight offshore patrol vessels have a helicopter facility. They also have very economical diesels, the top speed is only 22 knots.
The similiar New Zealand 85 meter offshore patrol vessels are slightly longer, allowing room for a helicopter facility, with a better sensors package for the broad Pacific, thereby costing around 40-45 million Euros. Although the New Zealand vessels don't have a 76mm gun, they do carry a 25-mm Bushmaster gun similar to their army's LAVs. New Zealand's OPVs are also ice strengthened, unlike Ireland's. I suspect one of the reasons why the Aker Yards commerically designed OPVs have been selling to a number of nations is their low price.
While many nations have built commerically designed warships of a larger size, for light carriers and amphibious shipping, most navies have built military designed warships for their fast attack craft, corvettes, and frigates. As I noted before, these OPVs aren't warships, they are not built to military standards, and are quite underarmed as compared to military designed corvettes. These OPVs are designed to fulfill the role of a fishery protection vessel, and patrol these nations EEZs. They could be useful for SAS surveillance deliveries in the dead of night. They are also useful in showing the flag abroad, but they are not of much use for anti-ship warfare, anti-submarine warfare, or anti-air warfare.
Even if a nation decided to add harpoon missiles, evolved sea sparrow missiles, anti-submarine torpedoes, and a close in weapon system, their electrical plant isn't large enough to supply the electricity, another reason why these ships are cheaper than corvettes. This is exactly the reason why the Famous class of US Coast Guard cutters have never received harpoon missiles or other weapons systems, where will the electricity come from?
Its amazing how much a nation can save buying a commerically designed vessel for commerial surveillance at any size. Military vessels have built-in reduntancies, larger diesel capacity, more electricity, more sensors, more speed, and thus more weapons. Think of it in this way: armies roll about in armoured vehicles, police roll around in unarmoured cars.
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