N.Z. Orions and under -water war

Press, 24 February 1984, Page 14

N.Z. Orions and under -water war

Nick Lee-Frampton, of Christchurch, who wrote this article, came to New Zealand from Britain 11 months ago. Before that, he ran a defence education group in Suffolk. Since coming to New Zealand he has retained his interest in defence matters.

Success usually carries tangible results, but to the men of R.N.Z.A.F.'s 5 Squadron, based at Whenuapai, Auckland, success is half-a-day spent loitering 1500 ft (457 m above the Pacific without sighting an intruder. On January 25 the squadron unveiled the first of its improved Orion maritime patrol aircraft. Late last year the squadron won (again) the Fincastle Trophy — the third win in only four years. The squadron’s fortieth anniversary of continuous service — it was formed in 1941 but disbanded a year later — will occur this July. As in fellow squadrons around the world. s’s five Orions spend their flying hours over the 75 per cent of the planet that is wet. The peace-time role is observing the Exclusive Economic Zone (E.E.Z.) that extends 200 miles from New Zealand’s beaches. In more turbulent times, their role would be the

same as their Australian. Canadian and British rivals for the Fincastle Trophy: anti-submarine warfare (A.S.W.). It is this aspect that is tested during the annual Fincastle competition. Not finding a contact can be regarded as much a success as detecting one: with the squadron's obvious expertise, it would be a rash skipper who took a submarine or surface-vessel into s's territory. No sightings indicate that deterrence has worked and a sighting, that deterrence has failed. Given the scant resources, the New Zealand squadron has gone well beyond what could reasonably be expected of it; the Fincastle victories have been against crews of countries whose A.S.W. forces have many more men, experienced and well-equipped in A.S.W. techniques, from whom competition crews can be chosen. A.S.W., although it attracts little publicity, is

an area of modern military science where secrets are kept and technology is pushed to the limit. In great-grandfather's time, the sea-border was taken to the limit of the then man-o'-war’s smoothbored cannon: three miles. Today, as in this country, the limit is set at 200 miles. That is a lot of water. In father's time, a submarine needed eight hours "breathing” a day to keep going, which meant a long exposure time, even though the A.S.W. aircraft of the time lacked most of today's sensors. Now a diesel-electric submarine requires only 30 minutes, and it does not need to surface.

I'hat several countries, including the United Kingdom and France, have chosen to place all or part of their nuclear deterrent in submarines is as good an indication as any of the difficulty of detecting such a warship. Indeed it is a primary reason: the traditional storage method — silos — has become increasingly vulnerable as the accuracy of enemy missiles has increased. Missile silos have come within the widening orbit of the recent military axiom that if you can see it, you can hit it.

You cannot easily ''see” a submerged submarine. The hunter is the Orion which, with two engines shut-down, can loiter for 17 hours several thousand miles from base. In the nose a radar scans for surface targets or a periscope: if the submarine uses radar itself then this is picked up and recorded aboard the Orion. If the submarine uses its periscope at night this can be seen by F.L.1.R., forward-look-ing infra-red, which turns night to day.

If the submarine does not protrude above the surface, it mayescape the attention of these sensors. but it could fall prey to M.A.D. — the magnetic anomalydetector. If you look at an orion. you will notice that the tail extends far behind the fin. tapering gracefully. This is necessary to ensure that the sensitive M.A.D. equipment is not affected by the aircraft’s own magnetism. If the Orion flies over a submerged submarine. the change in the magnetic field is recorded.

The third major area open to hunting Orions is sonar. Helicopters employed on A.S.W. can hover and "dunk” their sonar to listen for underwater noise. (This can be hazardous: a Japanese helicopter thus employed one night last year was hit by the mast of a passing ship.) Orions drop sonar-buoys that transmit to the orbiting aircraft.

All three areas, radar. M.A.D. and sonar, can be disrupted by the restless sea. The number of “whales” sunk by the R.A.F. and Royal Navy during the Falklands war is one example of the false signals that can fool the most sophisticated equipment and the most skilled crews. Rocks and wrecks can fool radar and M.A.D. gear too. Sonar must be tuned to the water state — the temperature at different depths, and tides and salinity all influence the ability to listen.

Submarines are in a similar plight, with the sea working for and against them. The law that says you cannot compress water gives an extra kick to an underwater explosion. Some countries use nuclear warheads on depth charges and torpedos. Accuracy need not be great for such devices to prove lethal, but they are intended for use against deepdiving and very fast nuclearpowered submarines deep in midocean. Inshore can lurk and hide the “conventional” submarines.

Although it does not have the endurance of a nuclear-powered submarine (which can remain submerged until the crew’s food runs out. usually 40 to 45 weeks), it can penetrate closer to the shore. This does not mean it is easier to detect. Shallow water contains strong currents, rocks, and manyfeatures which give a radar or sonar signal that could as well belong to a submerged submarine. For example there has been the recent fury of the Swedish armed forces who knew that their coastal waters harboured intruding submarines, but could not detect them. The one they did “catch" was forced to surface by an internal fault, rather than outside detection. All this is not to say that the nuclear-powered submarine is totally immune. Apart from nuclear depth charges, modern torpedoes bear little resemblance to the straight and level-running World War II versions. Today's torpedo is a guided missile. It has a homing head, and can twist, turn, rise and fall to reach the target. It can be programmed, for example, to hit an enemy submarine in the area of the nuclear reactor.

A ploy seen in many films is tor the submarine to keep very still and very quiet. Usually, in a film, a crew member drops a spoon or a spanner. The nuclear submariner may hold his breath, but the nuclear reactor cannot be turned off. It needs to be kept cool. This requires a pump, and they make a noise which is especially noticeable in Soviet submarines. Movement — and a modern nuclear-powered submarine can top 30 knots — makes the task of an acoustic-homing torpedo all the easier. If the target is an Alfaclass Soviet submarine, it is best to launch a torpedo in front of it. because these submarines can reach around 50 knots. That is faster than most current torpedos although Marconi, in England, has produced a torpedo to match and catch Alfa-class targets. This is the operational world that is the lot of 5 Squadron. No one can doubt that they are masters of their trade, the recent Defence Review spoke of submarines for the New Zealand Navy. They would provide good training for 5 Squadron’s crews. The Navy would find the competition fierce.