Why large deck structures

Jonsey- Interesting info. I notice that both the Arleigh Burke and T-45 have wider hulls than is usual. I imagine this helps stabilty but I wonder if it reduces speed. Looking at the specs, both ships seem to be able to reach normal destroyer speeds with regular powerplant specs. I find it intesting that the Arleigh Burke has variable pitch screws. I know the Spruance class can do 6 kts on its manueving motors, and thats with the considerable drag of the dead main screw. Being able to feather the mainscrew may allow the ship to cruise at station at decent speeds just on auxiliary motors for high endurance. I also noticed that the T-5 turbines will charge generators which will drive electric motors that turn the main screws instead of being directly connected to the shaft of the screws. I imagine this must enable auxiliary motors to run the main screw, however I dont know how efficiently the auxiliary motors would be able to turn such large screws. Have you served in the Navy?

Scooter

Wouldn’t consider myself resident anymore – far too busy these days I’m afraid, but, its nice to be thought of in such terms!.

You phrased your question in a very interesting way – ‘what design would you base….’. It was very astutely put as no currently extant design provides a really good fit to the RANs operational needs as I see them.

Australia’s huge maritime sphere-of-interest demands a rangey vessel and one capable of extended deployment. Australia’s reliable participation in coalition ops as far away as the Persian Gulf reinforces that need. I don’t see a Saschen, F100 or similar size hull providing sufficient capability in this regard.

That, ostensibly, leaves two players still at the table. The Flight2 Arleigh Burke and the Type45. Given the large production run of the Burke design it is likely that the acquisition costs of both vessels would be at least in the same ballpark.

Of these the favourite would seem to be the US vessel as it would require little modification to fit in with the rest of the fleet in weapons and logistics terms. It is also likely to have the edge in combat persistence being possessed of a 30% or so larger VLS installation.

Type 45 on the other hand would require redesigning to accommodate a fire control system compatible with ESSM/SM-2 (APAR or addition of a suitable X-band illuminator suite to mate up to SAMPSON), Mk41 VLS modules in place of the Sylvers, Mk45 5″ in place of the UK Mk8 and countless support and ancillary systems. Systems that would all require thorough integration and testing. An expensive process to spread over only a few hulls.

Hands down win for the Burke then?. Not for me it wouldn’t be!.

Despite all the issues involved adapting the Type 45 to Aussie needs I believe its very much the optimum solution for them. This is for two basic reasons:

1, SPY-1 has been around for a while and AEGIS sensor-fusion is a function replicated by most modern CDS suites. Both are still, very capable, battle-winning systems but on vessels optimised for service into the 2040’s I’m concerned SPY-1/AEGIS may not be sufficient for a first-line AAW escort?. T45 modified for APAR/VSR would be much closer to a future-proof solution IMO.

2, Running costs. The Burke FltII is a big ship with ownership costs to go with. Type 45 operates with 100 less crew and introduces low maintenance systems like Integrated Electric Propulsion (IEP). IEP connects the drive turbines to the screws via electric motors and ring main cabling removing the need for lined-up shafts, reduction gearboxes etc, etc. This also allows the prime mover turbines to be placed higher in the hull to ease maintenance and reduce vibration transmitted out into the water increasing the vessels acoustic stealthing.

Type 45 offers, IMO, superior range and endurance to all bar the Burkes, up to a 64-cell VLS up to Mk41 Strike-Length, space and weight margins to fit leading-edge sensors, ability to operate a Merlin-sized chopper, reduced maintenance overheads and modular construction that could see significant Aussie industrial participation in the build phase!.

…and your theory is perfectly accurate. The early ‘big-panel’ SPY-1 systems had quite hideous energy requirements and had large power/machinery spaces immediately behind the panels that utterly precluded a masthead mount. As it was plainly obvious that elevation was desired to push back horizoning and lessen the effects from multipath you ended up with the kind of tall superstructures that the CGN-9 USS Long Beach kicked off and for identical reasons.

Jonesy- Considering your the resident Naval Expert on this forum. In your expert opinion. What design would you base Australia’s forthcoming AWD Ships on?

Scooter

Mate who knows what the ADF is thinking, the RAN want the F-100, Industry want the F-124 and the current government want the DDG-51, so it’s going to be a toss up over who wins, personally I would have thought that the RAN would win out because they have to operate these for the next 30 years or so.

Ja- Politicians are the same the world over! Don’t hold your breathe…….. 😮

Well, Arleigh Burkes already look a lot better than Ticonderogas, from the perspective of height and such. IIRC, F100 employs a different type SPY than Arleigh Burke, so perhaps it is smaller and lighter, allowing for a reduced superstructure relative to Arleigh Burke.

AEGIS version in F-100 is SPY-1D (same that Burkes). May be last Burkes have a baseline more recent than F-100 (SPY-1D Baseline 4-5 in spanish vessels), but otherwise are identical to that in Burkes. Antennas are of same size and are at the same level. The difference is that the bridge in F-100 is under AEGIS…
Nansen has a smaller versíon SPY-1F.

…and your theory is perfectly accurate. The early ‘big-panel’ SPY-1 systems had quite hideous energy requirements and had large power/machinery spaces immediately behind the panels that utterly precluded a masthead mount. As it was plainly obvious that elevation was desired to push back horizoning and lessen the effects from multipath you ended up with the kind of tall superstructures that the CGN-9 USS Long Beach kicked off and for identical reasons.

Hey Jonesy, long time not hear! Ah yes, USS Long Beach! That’s another good ship to compare to with USS Virginia.

A lot has to do with how the electronics and the command & control facilities are located. In the case of the Spruance/Ticonderoga’s CIC is in the superstructure (the Spruance class already had an imposing superstructure prior to the CG mod)
The superstructure of these ships was light weight metals. Stealth was not factored into these designs as in the case of more recent ships so comparisions are necessarily valid.
There has always been an ongoing debate about where CIC should be located. In the current environment, the CO is generally in CIC during l/r engagments, but still needs to be close to the bridge. Some other designs have CIC in the hull so it is more difficult for the CO to split his time between locations.

I’m sticking to my theory that the superstructure size of the ships mentioned at the beginning of this thread is a function of the young ‘age’ of their AEGIS systems.

…and your theory is perfectly accurate. The early ‘big-panel’ SPY-1 systems had quite hideous energy requirements and had large power/machinery spaces immediately behind the panels that utterly precluded a masthead mount. As it was plainly obvious that elevation was desired to push back horizoning and lessen the effects from multipath you ended up with the kind of tall superstructures that the CGN-9 USS Long Beach kicked off and for identical reasons.

Spain’s Aegis Destroyer (Frigate?) has a lower silhouette than either the American or Japanese Aegis Destroyers. Is that one of the reasons that Australia seems to be leaning towards than design for there upcoming AWD Destroyers????

Well, Arleigh Burkes already look a lot better than Ticonderogas, from the perspective of height and such. IIRC, F100 employs a different type SPY than Arleigh Burke, so perhaps it is smaller and lighter, allowing for a reduced superstructure relative to Arleigh Burke. But if you then compare with the IZAR designed Nansen clas ships building for Normay, you see the fixed phased arrays are again smaller and have moved from superstructure to (still rather fat) main mast. The F124 variant with AEGIS instead of current APAR that was offered to Australia has yet smaller phased arrays, mounted on the same mast that normally carries APAR. I’m sticking to my theory that the superstructure size of the ships mentioned at the beginning of this thread is a function of the young ‘age’ of their AEGIS systems. Same thing really for Chinese 052C: as the chinese master the technology, you will see the arrays shrink in size and being mounted higher up, on masts rather than in superstructure, and subsequenty being installed also on smaller vessels.

Mate who knows what the ADF is thinking, the RAN want the F-100, Industry want the F-124 and the current government want the DDG-51, so it’s going to be a toss up over who wins, personally I would have thought that the RAN would win out because they have to operate these for the next 30 years or so.

Haha, so you guys are going to end up with a Dutch LCF after all 😉

Mate who knows what the ADF is thinking, the RAN want the F-100, Industry want the F-124 and the current government want the DDG-51, so it’s going to be a toss up over who wins, personally I would have thought that the RAN would win out because they have to operate these for the next 30 years or so.

The T45 Destroyers look impressive……………thought I would take a American or Japanese Aegis Destroyer anyday 😎

Interesting, I always thought the Arleigh Burke Class looked imposing and very powerful (as do the Kongo Class)………of course I have to admit that I am alittle bias. Being a American and all. 😎 Seriously, Ja your not saying that Australia considers the aesthetic appearance. More important the a ships capabilities :confused:

Yes Scoot it is mate, to tell you the truth not many were happy when the RAN bought the OHP design due to the designs brick wall frontage. They don’t want to go any higher than these and with the USN frequently visiting Sydney harbour all the time many have seen these ships in close inspection and are not happy with them, Asthetically speaking. I guess it’s another reason we didn’t buy the Kidds.

Well most of it does have to do with the electronics suite, and it centers around the Phased Pannelar Radar which you can see with those odd shapes, they take up a lot of room, and for the effective range they offer, you need them up high.

This is changing though, as electronice become more powerfull and smaller we will see a return to lower decks, the Meko offers have the Phased Array Radar on a pylon mounted amid ship and it rotates. this is not as good as the American system simply because it doesn’t provide total coverage all the time, which the American system does.

Spain’s Aegis Destroyer (Frigate?) has a lower silhouette than either the American or Japanese Aegis Destroyers. Is that one of the reasons that Australia seems to be leaning towards than design for there upcoming AWD Destroyers????

Ive noticed alot of navy destroyers and cruisers have huge structures on deck, but why? Why cant they just make the hull larger and put whatever compartments and equipment that are in the deck structures inside the hull? As funny as it sounds, the only reason I can think of is looks, a ship looks more formidable with large deck housings. But really the only thing they do is raise the center of gravity and unstablize the ship.

It is not a coincidence that all images you showed with your question are AEGIS equipped ships, with massive antennea which need to be placed somewhere other than on a mast. As you may notice, new generation SPY is getting smaller, small enough to be mast mounted.

Not all cruisers and destroyers have such a big superstructure. Check for example the USN Vriginia CGN. About the same armament as Ticonderoga but larger and no AEGIS.

I guess the reason for the Ticonderoga class’s bulky appearance is that it has the Aegis system jammed into the Spruance class hull.

Well most of it does have to do with the electronics suite, and it centers around the Phased Pannelar Radar which you can see with those odd shapes, they take up a lot of room, and for the effective range they offer, you need them up high.

This is changing though, as electronice become more powerfull and smaller we will see a return to lower decks, the Meko offers have the Phased Array Radar on a pylon mounted amid ship and it rotates. this is not as good as the American system simply because it doesn’t provide total coverage all the time, which the American system does.

why is that needed? since you have a full radar suit you can basically guide the ship by instument and maps…

BTW if you need the radar to be housed higher coulden’t you place it ontop of a mast instead of making the huge structures ?

They also raise the driver seat