Royal Australian Navy Discussions and Updates

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alexsa

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Arbitrary number (aka assumption math) pulled from my shipbuilding/design experience to give an example of how extreme adding weight up high can affect design margins. On one ship we added less than a ton of equipment to the top of the mast. It equated to 16 ton of ballast. Had to reinforce the mast, change the ladder arrangement, cooling for the equipment... As you noted dynamic stability is much more complicated than static and have greater impacts.

The carriage of ballast is actually very common on warships... that are converted from another design. If the Hunter was designed from the keel up there would likely be little to no wasted tonnage. As it's a modification of someone else's design then there will automatically be wasted tonnage, unless Australia is redesigning all the internal spaces. And then what was the point in buying someone else's design?

Maybe I'm wrong and the mast isn't the problem. Someone else tell me why the ship is 1000+ tons heavier.
My point is we are not across the actual changes being made to the vessel and there is no point guessing the impact. As this growth is being designed in before construction I would expect no unnecessary ballast being added. The article describes the reasons for the growth were detailed in general terms in the relevant interview. I doubt we are going to get more detail than that in the near term. The addition 1200 tonnes appears manageable with a slight increase in beam and block coefficient.
 

vonnoobie

Well-Known Member
Not to be taking over the moderator job but if I may suggest as we are discussing more and more into what we could acquire in the short term with free funds at present left over from the delayed programs it may be better to move this discussion further into the ADF thread as we are jumping into RAAF and potentially the army.

That said in regards to the Hunters at the moment it's all guess work on the weight, while I am enjoying learning more about ship designs and the very careful math needed to keep them upright without knowing exactly what amount of weapons are being fitted, or if there is any fitted for but not with, with out knowing the weight of the radar and mast or even knowing the exact ship dimensions it is at best guesswork. Hopefully in next 12 months or so we have a more definitive outlook on the ships size and initial capabilities.
 

hauritz

Well-Known Member
I would suggest the weight problems being experienced by the Hunter class are mostly to do with that massive radar mast. The Type 26 was originally envisaged as an ASW vessel with a far more modest radar fit. As usual Australia decided it wanted to cram as much capability as it could into the ship. The result is obvious.

On reflection we probably should have just built a few extra Hobarts and left the Hunter as a ASW frigate.
 

ddxx

Active Member
I am curious why they apparently went for a reprofiling of the hull, and we don't yet know the beam changes, and apparently no change in length. This would certainly seem to make the ship very broad and beamy, and the type 26 hull wasn't exactly dart like to begin with. Why aren't we evolving in length? 149m seems short for a 10,000t "frigate"
Hunter's L/B ratio (assuming 20.8 beam) is quite an outlier compared to most other surface combatants:

Mogami - 8.16
Anzac - 7.97
Hobart - 7.91
KDX-III - 7.76
Burke IIA - 7.75
Maya - 7.65
Constellation - 7.63
Hunter - 7.21
 

John Fedup

The Bunker Group
It will be interesting to see the actual diversity between the three T26 variants, especially Hunter and CSC. Is CEAFAR considerably heavier than SPY7? CSC will be likely be 8,000 tons plus, but certainly not approaching 10,000 (I hope not). The number of VLS cells is the big mystery for CSC.
 

Morgo

Active Member
Hunter's L/B ratio (assuming 20.8 beam) is quite an outlier compared to most other surface combatants:

Mogami - 8.16
Anzac - 7.97
Hobart - 7.91
KDX-III - 7.76
Burke IIA - 7.75
Maya - 7.65
Constellation - 7.63
Hunter - 7.21
HMAS Fat Frigate?
 

alexsa

Super Moderator
Staff member
Verified Defense Pro
I would suggest the weight problems being experienced by the Hunter class are mostly to do with that massive radar mast. The Type 26 was originally envisaged as an ASW vessel with a far more modest radar fit. As usual Australia decided it wanted to cram as much capability as it could into the ship. The result is obvious.

On reflection we probably should have just built a few extra Hobarts and left the Hunter as a ASW frigate.
So that would leave us with 5 or 6 capable AAW Ships with moderate ASW capability and 6 or 7 very good ASW frigates with moderate AAW as opposed to 12 capable AAW ships of which 9 have very good ASW capability. Personally I would take the latter.
 

Geddy

Member
The Hunter Class’s armament doesn’t seem particularly “regionally superior” or competitive if it only has 32 VLS cells IMHO. If we can add hundreds of tons of ballast to accommodate the superior technology of the CEAFAR system one would think that with the change in Australia’s strategic assessment ( that brought on the nuclear subs ), we would see the need for more missiles and therefore more VLS cells. And of course we don’t really know what the current situation with them is but it makes sense some of the extra weight is VLS cells.
 

alexsa

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HMAS Fat Frigate?
You should use the design waterline measurements (water-plane area) for that ratio as raked bow and stern overhand (or straight bow and stern - like the new French FTI design) can distort the outcome. This is called the water-plane coefficient of fineness. Using LOA and maximum beam (which appear to be those measures wiki gives) it is not a proportional measure.

Hence .... the T26 has a wider beam by 0.8m and is a smidge shorter than the AB Block 2A.
 

alexsa

Super Moderator
Staff member
Verified Defense Pro
The Hunter Class’s armament doesn’t seem particularly “regionally superior” or competitive if it only has 32 VLS cells IMHO. If we can add hundreds of tons of ballast to accommodate the superior technology of the CEAFAR system one would think that with the change in Australia’s strategic assessment ( that brought on the nuclear subs ), we would see the need for more missiles and therefore more VLS cells. And of course we don’t really know what the current situation with them is but it makes sense some of the extra weight is VLS cells.
Noting the design is still being finalised ........... why would you add ballast? There are a lot of assumptions being drawn from an interview that puts a pretty positive spin the the design process and its outcomes.

Yes the models show 32 cells. Is that final number ... no idea! Nobody in the project is talking and that is quite reasonable.

Ballast was added to ANZAC to build more growth into an existing vessel. The take away from the interview is that navy is looking for more growth and capability from ship one, not later batches.
 

Massive

Active Member
So that would leave us with 5 or 6 capable AAW Ships with moderate ASW capability and 6 or 7 very good ASW frigates with moderate AAW as opposed to 12 capable AAW ships of which 9 have very good ASW capability. Personally I would take the latter.
The Hunters will be very capable ships - would you consider their AAW capabilities to be the same as the Hobarts?

It will be very interesting to see how the Hunters evolve as they are built - the hull is large and it appears that this could form the basis of RAN major surface combatants for a very long time.

Technology is moving so fast and accelerating it is very difficult to know what a Hunter built in 2030 will look like.

Regards,

Massive
 

Todjaeger

Potstirrer
The Hunters will be very capable ships - would you consider their AAW capabilities to be the same as the Hobarts?

It will be very interesting to see how the Hunters evolve as they are built - the hull is large and it appears that this could form the basis of RAN major surface combatants for a very long time.

Technology is moving so fast and accelerating it is very difficult to know what a Hunter built in 2030 will look like.

Regards,

Massive
Honestly I do not think there is a way for us to know given that the actual Hunter-class FFG VLS cell count is unknown, and what the likely VLS missile load outs will be. In a similar area of unknowns, we do not know how the CEAFAR radars perform compared to the SPY-1D(v) radars fitted to the Hobart-class. I would expect the radar performance would likely be overall comparable, but whether or not one radar array has better optimization for certain ranges and/or certain type threats... AFAIK there is no public data to really allow such a detailed comparison.
 

StingrayOZ

Super Moderator
Staff member
we do not know how the CEAFAR radars perform compared to the SPY-1D(v) radars fitted to the Hobart-class
I thought the original intention was to fit CEAFAR2 to the Hobarts and deep six the Spy 1d(v). However there are some indications that they intend to upgrade them with at least SPY6(1) instead combined with an AEGIS baseline upgrade to 9 or 10. As Part of $5 billion upgrade. I would expect there would be similar issues mounting the Hunter configured radar to the smaller Hobart hull.


There are plenty of print articles that hint or indicate or make unsupported statements like the CEAFAR2 will be far superior to the 1D(V). Which isn't that surprising as the US licensed some of CEA technologies for their newer products. Northrop acquired a 49% of CEA back in 2006.

An unmodified design might be controversial when it comes to the choice of radar: while the Australian-made CEAFAR radar is reputedly superior to the AWD’s SPY-1D radar in performance, and is the radar of choice for SEA 5000, using the SPY-1D would allow us to reap the benefits of the US Navy’s integration testing regime.
However, as you say, public data is going to be thin on the ground. The 1D's are quite dated if powerful radars.

I am curious that the Hobarts and the Hunters are just exactly 149.9m long. Is that a build limitation? The sea lift isn't exactly roomy with a Anzac and I recall it maximum lift weight was getting up to the size of the hunters. The ship lift in theory can lift ~156m and ~9,200t.. But like many maximums there can be in practice limitations.
 

ngatimozart

Super Moderator
Staff member
Verified Defense Pro
This continual "redesigning" of the Hunter Class FFG, continual speculation on its dimensions, number of VLS cells, Centre Of Buoyancy, COG, light displacement, fully laden displacement, and everything else when very little is in the public domain and the design isn't even finalised, has become repetitive and tiresome. Posts concerning this along with suggestions of building a fourth Hobart Class DDG, arming the Arafura Class beyond what the RAN has already determined to be fitted, acquiring used SSNs, are to cease forthwith. This is non negotiable and any transgressors most likely will find themselves on holiday from this thread without any further warning.

The Moderators and the DEFPROS are completely fed up with the ill-informed and ill-considered posts that have been polluting the thread recent times. Whilst we understand that posters are passionate about the topic, the vast majority of you have been on here long enough to know what is expected quality wise in your posts.

In order for posters to digest this information, this thread is locked for Moderator discussion.
 
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