AUKUS

[ORAC]

Forecast - and probably why the UK were included in the plans….

AUKUS

[Dryce]

Originally Posted by Going Boeing

As Rattman said, it’s the depth of water around the harbour that is important.

In deep water, the submarine can change depth to sit just above or below temperature inversions to reduce the chances of detection from noise produced by the boat. In shallow water, the submarine captain has fewer evasion choices so enemy ASW assets (including submarines) can focus on the waters around the harbour to pick off submarines entering or leaving.

You don't usually park your expensive SSN close to harbour worrying about layers and temperature.

The advantage of being close to deeper water is speed of deployment.

A SSN can trundle about the depths at sustained speed. But there are are operational consrtaints. It needs a specific range of depth to do that speedy trundling safely in peacetime with a decent amount of water above and decent amount below.

So if you sit your SSN harbour facility somewhere where there are 100s of km of shallow waters to transit then getting the boats in and out means a slower transit time - if you lose a couple of days or more getting out and the same again getting back then that reduces time on station and adds to your lifetime costs.(Losing 4 days on 90 day patrol is 5% over the lifetime). If you end up doing much of that transit on the surface then you're visible and vulnerable.

[rattman]

and there might only be a limited amount of routes out

Its why australia doesn't base any real surface combatants inside the barrier reef. Theres only limited routes through the reef and its easy to block these with mines or other forces

[Flap Track 6]

My employer is a supplier to the Astute program and has been picking up talk of additional equipment orders. Spares? Overhaul float stock? Additional boats?

[Going Boeing]

Originally Posted by Flap Track 6

My employer is a supplier to the Astute program and has been picking up talk of additional equipment orders. Spares? Overhaul float stock? Additional boats?

Thanks for that, FT6. The Astute class is attractive for the RAN because of the lower cost and smaller crew but there are significant concerns about the PWR2 reactor being 8 years shorter life (than the Virginia’s S9G) and the reactor cooling system requiring electrical pumps to always be running whereas the S9G can produce reasonable power levels with convection cooling - very important in event of a total power failure.

I think that the RN needs additional Astutes in these uncertain times as 7 boats is insufficient to have a presence where the UK has global interests. They may be gearing up to build more of them along side of the Dreadnought assembly. Alternatively, additional spares is definitely a possibility to support the current Astutes if their utilisation has to be significantly increased.

[rattman]

Originally Posted by Going Boeing

I think that the RN needs additional Astutes in these uncertain times as 7 boats is insufficient to have a presence where the UK has global interests. They may be gearing up to build more of them along side of the Dreadnought assembly. Additional spares is definitely a possibility to support the current Astutes if their utilisation has to be significantly increased.

Also take into account astute will only have about 10 years left of its programmed life left when agincourt commissions into fleet

[ORAC]

Going_Boeing,

As I understand the original PWR2 reactor is no longer in production and has rep been replaced with the PWR3 based around S9G with thirty percent fewer parts as planned for use in the Dreadnaught class - and the last of the currently planned Astute.

And, of course, the SSNR…

https://www.navalnews.com/event-news...ack-submarine/

https://en.wikipedia.org/wiki/Rolls-Royce_PWR#PWR3

[rattman]

Thats the way I understand it as well, they would either have to restart the production of PWR2's or shoe horn in a pwr3 into the astute hulls. Cant imagine anyone who knows enough about the sub/reactors would start talking about it on public forums. So we will be still be waiting another 12 months of so to see what thier plan is.

The astues in building all have pwr2's. The SSN(X) will be designed around PWR3

[Going Boeing]

That’s also my understanding.

I did read one article that said the PWR3 cannot be downsized to fit into the Astute’s hull - if that’s the case, then I can’t see any more Astutes being built.

Any additional RN SSN’s will have to be SSNR’s but by the time they start getting them into the water (after the Dreadnought SSBNs have been completed), the first of the Astutes will be retiring.

[ORAC]

Update on Virginia/Columbia production schedules.

https://www.defensenews.com/naval/20...last-delivery/

Electric Boat readies to deliver attack sub Oregon, almost two years after last delivery

[Going Boeing]

It’s claimed that the Collins class submarines are constructed of a lighter, yet stronger steel than the HY100 steel used in the Virginia class. It’s also easier to weld and has better blast properties. The following article was written when the French designed Attack class submarine was being developed for the RAN. It shows that considerable effort was being made to design the best steel possible for the generally warmer waters that the new submarines would be operating in.

https://www.australiandefence.com.au...erial-advances

It will be interesting if this steel technology can be used on the SSN that is chosen for the RAN. It may introduce extra design costs which is not desirable when the intention is to build a mature “off the shelf design”.



Also, the Collins class has X configuration of the aft control surfaces which give improved manoeuvrability and less drag as they are smaller in size. This setup works very well in shallow water operations. It also has more effective control when turning the submarine whilst at high speed - it’s easier to compensate the tendency for the bow to drop. The surfaces are less affected by disturbed water from the sail, etc. Neither the Astute or Virginia class have this configuration but the new Columbia class SSBN will have X configured control surfaces.

[golder]

Regardless of the click bait articles and the real, initial issues. The Collins is still a world class sub. It does well in the joint exercises. Though ready for a major update.

[rattman]

Indonesia is apparently in final stages of buying some scorpenes from france

[Not_a_boffin]

Originally Posted by Going Boeing

It’s claimed that the Collins class submarines are constructed of a lighter, yet stronger steel than the HY100 steel used in the Virginia class.

Steel doesn't get appreciably lighter. What you end up doing is using higher strength steel which allows you to reduce thickness and hence weight of structure. However, that's only if the fracture toughness properties allow it to absorb the fatigue damage the boat will see, allow for welding imperfections/flaws and resist both crack growth and high strain-rate loading. Plus be able to be formed and welded with acceptable levels of pre-heating etc, etc.

Tricky stuff submarine steel.

[ORAC]

The future? Perhaps initially for submarine UAVs. Gets around MAD as well….

https://www.techradar.com/news/impos...r-and-sturdier

Scientists from the Massachusetts Institute of Technology (MIT) have created a new material using a new polymerizing process. The material, called 2DPA-1, a type of polyaramide, is said to be as light as plastic and as strong as steel; even better, it can be manufactured at industrial scale which bodes well for its go-to-market timeframe.

The material, which is the first polymer to be polymerized in 2D, adopts a planar structure, as opposed to a string one; think spaghetti lines and lasagne sheets. The team, led by Michael Strano, the Carbon P. Dubbs Professor of Chemical Engineering at MIT, managed to crack a problem that has left many generations of Ppolymer scientists befuddled.

2DPA-1 can sustain deformative forces up to six times greater than bulletproof glass and has a yield strength (the force required to break the material) 12 times that of steel at equal density. Another intriguing property is that it is impermeable to gases which could mean waterproof ultrathin coatings…..

[Asturias56]

"I think that the RN needs additional Astutes in these uncertain times as 7 boats is insufficient to have a presence where the UK has global interests. They may be gearing up to build more of them along side of the Dreadnought assembly."

Not possible I understand - Barrow can just about produce a submarine every 3 years or so. They don't have the manpower and certainly not the trained manpower to do any better - in fact they often do worse. The cost of a new line would be incredible. Construction of Astutes was timed to end as serious construction of the new SSBN's started. They have to be built first and in the meantime the Navy is looking at the design for the Astute successor

https://www.navalnews.com/event-news...Astute%2Dclass.

Our American friends often post about the problems they have with two constructors in getting vessels out on time.

[Going Boeing]

The Brits are finally starting on the dismantling of their nuclear submarines that have been stored for many years at Devonport. The work will be done at the Peel Ports Inchgreen Dry Dock, west of Glasgow.

First nuclear submarine to be recycled



UK Nuclear Submarine storage at Devonport

Peel Ports Inchgreen Dry Dock

[Not_a_boffin]

Originally Posted by Going Boeing

The Brits are finally starting on the dismantling of their nuclear submarines that have been stored for many years at Devonport. The work will be done at the Peel Ports Inchgreen Dry Dock, west of Glasgow.

I'd always take everything Luke Pollard says with a bucket of salt. Aside from anything else, the first of our boats going through the recycling process are in Rosyth.

Both Rosyth and Devonport will be removing the LLW and ILW from within the boat, in the docks there. After that point, it is possible that they could be taken elsewhere for cutting up, but that's far from a done deal. Submarines are not known for their benign towing characteristics and a long sea tow (round Lands End and up the Irish sea or round the top of Scotland through Pentland) adds risk. I wouldn't bet against them actually being cut up on site.

[Going Boeing]

Good points N_a_B.

This is the Government position on the disposal UK Nuclear Submarine disposal



UK Nuclear Submarine storage at Rosyth

This article also backs up your thoughts about the dismantling likely to be done on site. Navy Lookout RN Submarine Dismantling

Your observation about the difficulty of towing a submarine appear to be correct which is why they fit reusable tow bridles to decommissioned US Navy submarines when they are to be moved.



Decommissioned USS Baton Rouge fitted with a reusable tow bridle around the bow.

[Going Boeing]

It looks like the decision on which submarine and where it will be built will be announced before the next Australian Federal election is called.

Defence Minister Peter Dutton says AUKUS subs deal being fast-tracked