Royal Australian Navy Discussions and Updates

[Firn]

There are several ways to increase the payload of an existing design without large modifications of the submarine. Mines and containerized torpedos or decoys can carried externally. Naval mines come in myriad forms and functions, but can be extremely effective especially in conjuncture with other assets.

Subs can be the minelayers of choice. The Gotland class for example can carry 48 of Saab's Type 42 mine based on the Torpedo 27 externally. Other torpedos or missiles might be used too and integrated into a ForceNet.

 

[StingrayOZ]

Well, if it would be expensive to redesign the Hobarts to take the gun even at an early stage, that's the major rationale for having it blown out of the water...

We went with the F-100 design because its tested, a known quantity, with realistic costs and timeframes and does everything we want it to do. Altering it to take a unproven naval gun that will cost more, offer us nothing tangible over a proven and very capable design. Why spend 250% more to get 105% more capability.

While a 155 might be the sort of thing you want on a rolling technology demonstrator (Zummers) they aren't what Australia needs. And for the price we could get so many other things.

Are they okay in the corrosive environment? I thought most equipment got chewed up pretty fast if it wasn't specifically designed for it.

Well I would expect the Tiger to become more marine friendly through out its life. However there are cases of helos being used even though they haven't been significantly adapted. Operating off a LHD should not give major problems.

 

[gf0012-aust]

We went with the F-100 design because its tested, a known quantity, with realistic costs and timeframes and does everything we want it to do.

It was not the first preference by a long shot.... Flag wanted the G&C design

 

[PeterM]

It was not the first preference by a long shot.... Flag wanted the G&C design

How did the Gibbs and Cox design compare to the Hobart design?

 

[gf0012-aust]

How did the Gibbs and Cox design compare to the Hobart design?

Stepping into legal issues here so limited in my capacity to comment.

The F100 was not the preferred vessel by some serious Flag level ranks and Tac planners.

Future proofing and weapons loadout were common issues.

Also the Norwegians have been very vocal to RAN in expressing disappointment with their spanish builds

 

[hairyman]

The quality of the Spanish ship building wont be a problem for the AWD's since they are being built here. But it may be for the two bigger ships being built over there.

 

[StingrayOZ]

Still it was the reason why they were chosen (that and cost).

I don't see a massive flaw with the F-100 design. If it can be upgraded to 64 VLS and have weight/space margin for other radar/misc upgrades then it should be acceptable. Not idea, but acceptable and way better than what we have now.

As for dealing with the spanish companies, I think that will be a whole other bundle of eggs. I don't know enough, but from what we hear its not great.

At least we are building the AWD here, and the LHD will be fitted out here so we aren't buying keyturn units and will be involved in the build closely.

 

[tphuang]

VERY expensive and quite unnecessary too. The 127mm gun that will be going on the Hobart Class Destroyers (Mk 45 Mod 4 as opposed to Mk 45 Mod 2 on the existing ANZAC class) matches the range of current land based 155mm guns without -ER rounds, ie: up to 40klms.

Extended range rounds for 127mm naval guns have demonstrated ranges beyond 60k's. Even further ranged ammunition (Vulcano, ERM etc) is under-development and showing good promise, with the initial Vulcano rounds at least, demonstrating 60k ranges. Later editions are intended to demonstrate 100k + ranges.

Range won't be an issue with 127mm guns for the next few years I should imagine...

Just wondering, what is the weight + space requirement for something like a 127 mm naval gun? I'd imagine firing something to more than 100 km away would require more sophisticated or large gun mount than firing something to 40 km.

 

[winnyfield]

Just wondering, what is the weight + space requirement for something like a 127 mm naval gun? I'd imagine firing something to more than 100 km away would require more sophisticated or large gun mount than firing something to 40 km.

USA 5"/54 (12.7 cm) Mark 45 Mods 0 - 2
~24t (vs ~84t for the 155mm AGS)

Extended range munitions usually are rocket assisted rather than bigger charges; larger mount not needed (see land based artillery eg m777).

 

[Aussie Digger]

Just wondering, what is the weight + space requirement for something like a 127 mm naval gun? I'd imagine firing something to more than 100 km away would require more sophisticated or large gun mount than firing something to 40 km.

Depends on the lower hoist, but figures with a "four flight" lower hoist, for the Mk 45 Mod 4, are a maximum weight of 24674kgs.

Not sure if that includes ammunition or not, but the typical magazine capacity for these weapons is 500 rounds of "standard" ammunition, with reduced capacity if -ER ammunition is carried.

As to the -ER munitions, the increased ranges are typically obtained by modifications to the actual ammunition rather than the gun mount itself.

Rocket assistance, "base-bleed" projectiles (whereby inert gas is dispensed from the rear of the project which forces the air flow around the rear of the munition rather than straight over the end of the munition, and thereby providing a range increase) and "sub-calibre designs, employing sabot designs.

The Vulcano is an example of the sabot system, with a sub-calibre (ie: reduced sized warhead) being the design trade-off allowing extra range.

Here's a fairly crappy video explaining Vulcano...

YouTube - oto melara Vulcano precision projectile

 

[PeterM]

Stepping into legal issues here so limited in my capacity to comment.

The F100 was not the preferred vessel by some serious Flag level ranks and Tac planners.

Future proofing and weapons loadout were common issues.

Also the Norwegians have been very vocal to RAN in expressing disappointment with their spanish builds

I assume the F-100 was considered more cost effective (basically alot cheaper) than the Gibbs and Cox design which was a much more capable platform.

From an external perspective, I find this curious considering we have and could likely leverage cost savings by tacking on the USN supply train for the Arleigh Burkes.

from Hobart class destroyer - Wikipedia, the free encyclopedia

"Media reports in March 2007 indicated that the F100 bid was "ahead on price, risk and scheduled delivery when compared with the evolved design offered by Gibbs & Cox", though the head of the RAN, Vice Admiral Russ Shalders, stated that he believed that the modified Arleigh Burke design would provide the RAN with a greater long-term capability."

 

[old faithful]

Still it was the reason why they were chosen (that and cost).

I don't see a massive flaw with the F-100 design. If it can be upgraded to 64 VLS and have weight/space margin for other radar/misc upgrades then it should be acceptable. Not idea, but acceptable and way better than what we have now.

As for dealing with the spanish companies, I think that will be a whole other bundle of eggs. I don't know enough, but from what we hear its not great.

At least we are building the AWD here, and the LHD will be fitted out here so we aren't buying keyturn units and will be involved in the build closely.

F100 design flaw, well its not really a flaw, but for an asset as important as an AWD, surley 2 helo,s would be prefered? Or at least enough hanger space for a UAV as well as a Helo?

 

[StingrayOZ]

Yes they should have 2 air units (helo and UAV) which I've heard/belive is possible.

How I don't know. Theres not enough in the public domain to make many comments about the F-100 given that ours will apparently be 750t larger yet no details are avalible how that is done.

 

[Abraham Gubler]

Yes they should have 2 air units (helo and UAV) which I've heard/belive is possible.

How I don't know. Theres not enough in the public domain to make many comments about the F-100 given that ours will apparently be 750t larger yet no details are avalible how that is done.

Well I think I've posted here and written in various places on multiple occasions some comments about the F100 hangar space and the larger displacement. Since participating on these forums mean you have to repeat yourself every three to six months or so, here goes:

Firstly there is no room for a double hangar because of where the torpedo magazines are positioned. Because like most magazines these are in blast proof walls you can't simply move them around like offices and other spaces within a ship. That is without major redesign - which is not happening for the AF100 from the F105.

There is some space to expand the size of the hangar because to starboard of it is a long passageway. Extending the hangar into this passageway space would add another 2m or so of width to the hangar allowing for a few medium to small sized UAVs to be stored with a 10 tonne class naval helicopter. It would require some redesign of the AF100's NBC citadel.

 

[StingrayOZ]

I try to keep abreast of most of the threads here and at SP and other forums.

So how is our AWD getting larger? Is it just shuffling around a few internal walls or is it larger draught or redesigned hull. Until the WP it was 6,250t, I have printed material from ASC that it is 6,250 now after the wp its 7,000t.

While moving walls around will allow for a UAV, unless the hull is further in the water or is of larger dimentions its not getting any bigger than 6,250t.

 

[old faithful]

Thanks for the info Abe, it is appreciated. Sorry you have to repeat yourself mate.....

Im not convinced the navy is getting the right hull for the job.
It seems we want more of an "all rounder" than a true AWD, and thats great, but for a true allrounder, i think we are gonna need 2 air assets. ASW, and an anti surface, general duties chopper. Maybe this can be acheived by UAV?

 

[gf0012-aust]

It seems we want more of an "all rounder" than a true AWD, and thats great, but for a true allrounder, i think we are gonna need 2 air assets. ASW, and an anti surface, general duties chopper. Maybe this can be acheived by UAV?

There's a limit to what current UAV tech can achieve... The tech changers for UAV's will probably be realised for the US in 2015, but for Aust, where we try to stay within 2 generations of interoperability releases, then we're getting closer to a 2020 date.

 

[PeterM]

So how is our AWD getting larger? Is it just shuffling around a few internal walls or is it larger draught or redesigned hull. Until the WP it was 6,250t, I have printed material from ASC that it is 6,250 now after the wp its 7,000t.

I believe the assumption for a 7,000t AWD has come from the 750t future capability margin the RAN wants for the Hobart class (bringing the 6,250t design up to 7,000t) combined with the assumption that the Anzac replacement (listed at 7,000t in the white paper) will use a common hull with the Hobart hull (leveraging established technologies, facilities and experience developed).

I don't know how this extra 750t future capability margin alters the actual ship design, hopefully some people with more technical/ship building knowledge can help.

 

[Abraham Gubler]

I try to keep abreast of most of the threads here and at SP and other forums.

So how is our AWD getting larger? Is it just shuffling around a few internal walls or is it larger draught or redesigned hull. Until the WP it was 6,250t, I have printed material from ASC that it is 6,250 now after the wp its 7,000t.

While moving walls around will allow for a UAV, unless the hull is further in the water or is of larger dimentions its not getting any bigger than 6,250t.

A ship's displacement is not an indication of how big it is (size), but how heavy it is. You can increase the displacement of a ship without increasing its hull size. Usually what happens is the ship sits deeper in the water.

The F100 hull was designed with extra growth weight - that is you could increase its displacement by adding more weight to it without making it sit too deeply in the water to effect its operation. The AF100 will have an additional margin of growth weight, up to 7,000 tonnes (10% more). This doesn't have to involve making the hull longer or wider or adding another deck (far from it) but can be achieved by improving the stability margin and ensuring that at the draft from 7,000 tonnes the decks won't flood.

The US Navy's DD 963 hull started at 7,800 tonnes and ended at 9,590 tonnes (CG 47) a growth of 23% without changing the basic size of the hull.

 

[alexsa]

A ship's displacement is not an indication of how big it is (size), but how heavy it is. You can increase the displacement of a ship without increasing its hull size. Usually what happens is the ship sits deeper in the water.

The F100 hull was designed with extra growth weight - that is you could increase its displacement by adding more weight to it without making it sit too deeply in the water to effect its operation. The AF100 will have an additional margin of growth weight, up to 7,000 tonnes (10% more). This doesn't have to involve making the hull longer or wider or adding another deck (far from it) but can be achieved by improving the stability margin and ensuring that at the draft from 7,000 tonnes the decks won't flood.

The US Navy's DD 963 hull started at 7,800 tonnes and ended at 9,590 tonnes (CG 47) a growth of 23% without changing the basic size of the hull.

All correct. If we assume a TPC of 15 tonnes then the draft increases by 0.5m. A TPC of 20 tonnes (maybe a littel high) then the draft incrase is about 0.37m. For ships with very flared hulls (such as those on a warship) the TPC increases with draft as the increased waterplane area increases bouyancy so perhaps it is possible that the drat increase will be relatively small (again I don't have the detail ot put a value figure on this).

Most hulls have a scope for variation in draft but this depends on hull design. On most cargo ships the draft range is very large but the ship is less econmocial at some drafts. For other ships such as passenger vessels and warships the draft range tends to be a lot less as the hull design is optimised for higher speed and are intended to operate within a limited draft range.

In short you can go deeper and the ship design should have a level of flexibiltiy to accept this, however, increase the draft too much and the resultant increase in drag and water to be displaced will have an adverse impact upon performace in relative fuel burn and speed.