The new ship to replace the navy's ageing tanker, Endeavour, could have some serious weaponry to fight off pirates.
The 23-year-old Endeavour will be replaced with a new ship in 2018 at a cost of about $250 million.
Navy planners looking at the best ship to order said the new ship would at the least have .50-calibre machine guns and other measures to ward off pirates.
Endeavour was built on a commercial tanker design in Korea and modified for the navy as a fleet replenishment ship, which could refuel other ships at sea, carry stores and operate a helicopter.
However, it had no weapons on board other than 5.56mm Steyr assault rifles and pistols. The navy said it was looking at following global trends to give the new ship the ability to fight off pirates.
Commander Tony Hayes, the navy officer in charge of the acquisition programme, said as well as .50-calibre machine guns, they were also looking at a deck layout which would allow a mounting for a rapid-fire Phalanx Gatling gun similar to those fitted to the Anzac frigates, Te Kaha and Te Mana.
The 20mm, radar guided, close-in weapons system is used to ward off missile attacks, strike aircraft and fast inshore attack boats and could fire up to 4500 rounds a minute.
''We would consider in the design placement for such a thing. If you look at what the other major navies are doing, they are considering self defence weapons on these types of ships.''
Cdr Hayes said as more navies opted for more multi-role ships, including ships like HMNZS Canterbury and the Endeavour replacement, they did not have as many warships.
''These multi-role vessels are having to do more jobs and independently.''
''We would want appropriate anti-piracy measures.
Anti-piracy measures could include high pressure water systems, barbed wire and ''all sorts of attachments you will see on a lot of the major oil tankers.
''It is to physically to stop people climbing or putting grappling irons on the sides of ships.''
Endeavour will become non-compliant with International Maritime Organisation requirements in 2013 and be reclassified, with its cargo volume reduced.
Two years ago the navy spent about $2m closing off some of the tanks to effectively give it a double hull, reducing the capacity by 25 percent to about 5500 tonnes of fuel. From 2013 it would be limited to 5000 tonnes of fuel.
The replacement ship was likely to be more versatile than Endeavour but it would retain its main function as a fleet tanker.
''If budget permits and the base design permits we would like to see it with additional craneage, the ability to take a lot more containers and maybe support amphibious operations too.''
The ship would also be able to land the air force's new NH 90 helicopters and the navy's Seasprite helicopters and carry limited numbers of troops.
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