Leslie true the Collins is stealthy, but it doesn't need much stealth to get from Perth to Broom, about the extreme extent of it's cruising range, between major maintenance efforts involving a dock yard.

Mac, we used to have long drawn out wars, but it is unlikely we will have another major war like that. ICBMs fly too quickly for that. The best way to loose any war is to be fighting with the last one's equipment & attitudes.

In any future major war, it will be all over quicker than you could draw up the plans for a sub, let alone build one. No the next war, [if one occurs], will go to the party best equipped to fight it today, not next week, or in our case next decade.

With Labors ripping of 4.5 Billion out of the defense budget, we will be a sitting duck for damn near anyone, if the US don't find us valuable enough to defend.

We have now discarded the only weapon we had capable of projecting power any distance, the F111s, & hope a bunch of last century subs will do anything.

Perhaps we could buy a fleet of ocean going tugs, to tow our subs from the end of the earth in Perth to where they may be needed. They sure can't get there themselves.

Stezza and Leslie,

The Collins class submarine is one of the stealthiest and potent non nuclear submarines. However, the very nature of non nuclear power subs that require diesel generation is that the majority of the distance they travel is at best partially submerged as the diesels need air. Nearer the target they can submerge and travel on batteries. While partially submerged they are not nearly as stealthy as nuclear powered subs, that can travel for months below the thermocline which makes them almost completely undetectable. The storage of the batteries and diesel limits the range and payload of the subs.

Secondly once submerged, the speed and range of the subs is severely limited by the capacity of the batteries, and the ability to escape after an attack is limited. Whereas nuclear subs can travel far faster than surface vessels at greater depths.

Size for size, dollar for dollar the nuclear submarines have capabilities far beyond the diesel subs.

Well we need to decide what sort of submarine (and how many) based on the capabilities we require, rather than just looking at the stats (cost, speed, range). Do we really need to travel across the other side of the world, launch ballistic missiles and then escape rapidly? For a nuclear armed power like the US the answer would be yes. For Australia, I'm not so sure. I think the capabilities we require are more in line with intelligence gathering and posing a threat to a potential invasion force near our shores and their supply lines. In this situation range and speed are less important, and stealth is key. A disadvantage of nuclear power is the requirement for cooling pumps to be active at all times. Unlike diesel engines which can be shut off when needed. That said I have no problem having a mixed fleet, if the extra costs and numbers can be justified by capability need. However we need to start at the capability question.

The Centre for Independent Studies report released today says Virginia-class nuclear attack submarines would be bigger than any conventional submarine Australia could buy or build, so they could carry more weapons and equipment, travel much faster, and cover immense distances without needing to be refuelled.

Report author Simon Cowan, a research fellow at the centre, says in the report that the government's promised Future Submarine Project is a risky proposition. "The government is ignoring submarines that offer better value for money," he says.

"Australia needs world-class submarines and the US Virginia-class looks like the best option.

"Nuclear-powered submarines are superior in almost every way to diesel-powered submarines -- they can travel further, faster and stay deployed for longer, and they have more powerful weapons, systems and sensors."

Mr Cowan notes that the safety record of the US Virginia-class subs is flawless. "These subs don't carry nuclear weapons and never need refuelling and if Australia leases them from the US, the US could dispose of spent nuclear material," he says.

"While establishing an Australian nuclear program would have its challenges, leasing eight Virginia-class submarines is a capable, reliable and safe option for our naval servicemen and women.

"Australia could also save more than $10 billion by leasing eight Virginia-class submarines and up to $750 million a year on operational and maintenance costs as well."

Of course it would be cheaper still to buy Scorpene class subs directly from France. Making them here simply costs a fortune.

I can only repeat that the Australian Government will make its decision according to the global strategic requirement of America, specifically its containment of China policy, to which Australia is committed ( marines in Darwin etc). And all the evidence points to the Collins because of its superior stealth role.Leslie

As I proposed in my first posting,this debate on the relative merits of the Collins and nuclear subs is irrelevant, as the decision will be made according to the dictates of the American Alliance which will require Australia to contribute to the containment of China. Forget the exaggerated nonsense about its deficiencies; the US Brass know better; they have been studing it carefully in joint exercises.Leslie