Cheap DDH?

hawkdriver05,

The US Navy and Marine National operate nuclear carriers, they don’t have to worry about intakes and exhausts for their proplusion system.

The Invincible class has a single island that takes up huge amounts of flightdeck and hanger space due to the gas turbine proplusion system taking up lots of below deck space. The 2 island design will be a great improvement.

I’m sorry….but your arguments make no sense……..ALL necessary functions can be combined in a single island….this has been the choice for over 60 years…….an aircraft carrier should have maximum unencumbered deck space devoted to aviation……..by its very nature a carrier will be vulnerable to damage……..its the trade off for efficiency in aircraft operations…….and until the US Navy or Marine National adopt this “two island” concept, I’ll stand by my argument for a single one. Sorry if my not accepting your viewpoint offends you, but I’m actuly quit flattered that my opinion means so much to you.

Nobody said all necessary functions can’t be combined into one island. That is not the point. The point is that both the BEA and the Thales teams have put forward designs which split the island and the ‘ship’ and ‘air’ control functions. Perhaps you should also compare the number and location of the aircraft lifts on these proposals with e.g. US designs. Remember, the designs currently put forward for UK design are a lot smaller than US carrier.

The only arguments you provided in favor of the single structure are: a) maximum deck space available to AC (which is a poor argument because you can have 2 smaller islands which together take up as much space as 1 single large island leaving the same amount of available deckspace for AC) and b) it’s always been done that way therefor it must be optimal (which is a poor argument because if it has always been the case that there was only a single island structure then how would you know it was optimal: you can’t know how well or poor a double structure would function).

The fact is these proposals have split islands. I doubt these companies would make such a proposal without carefull study and simulation. I trust they are better engineers than I am. Hawkdrivero5, is there any particular reason for us to assume your shipdesign expertise and qualifications ar eany better than theirs?

Sorry if my not accepting your viewpoint offends you, but I’m actuly quit flattered that my opinion means so much to you.

Oh dear now here is a quandry. Does one confirm these egotistical ramblings by continuing to try and change your opinion or does one retire from the field and grant “victory” by default 🙂 Luckily I don’t think the remarks were directed at me and I don’t really care anyway.

I’m sorry….but your arguments make no sense……..ALL necessary functions can be combined in a single island….this has been the choice for over 60 years…….an aircraft carrier should have maximum unencumbered deck space devoted to aviation……..by its very nature a carrier will be vulnerable to damage……..its the trade off for efficiency in aircraft operations…….and until the US Navy or Marine National adopt this “two island” concept, I’ll stand by my argument for a single one.

I believe it has already been mentioned that the islands, apart from C&C functions, also house the intakes/exhausts for the CVF propulsion units. Now you cite the fact that this arrangement has not previously been seen. Granted.

However we are yet to see a CV powered in such a manner. All the large carriers have been steam turbine powered with either oil fired boilers or nuclear reactors providing the steam. The CVF will most likely have an electric propulsion system driven by gas turbines. One of the features of gas turbines is the compartive bulky trunking to carry the associated volumes of intake and exhaust air. this excerpt from one of the pages its been suggested you read a number of times gives decent overview of why the current configuration was chosen.

The optimum location for the position of the main propulsion system was carefully examined in early CVF studies, with the need to maximize the hangar space below decks a major consideration. The gas turbine generator units could be mounted in the superstructure, this would require a large island and reduce the flight deck area, but by avoiding volumous air intake/venting trunking to low machinery spaces will enable a larger and wider hanger. The comparative advantages of the two layouts was extensively debated within the DPA and the two competing industrial teams, but operational analysis and aviation generation studies demonstrated that the extra flight deck space associated with a small island(s) would be more valuable than the extra hanger space, so traditional main hull located engine rooms were selected. In the chosen Thales design, the two engine room units are widely separated, each one directly below an island to minimise the length of air downtakes and exhaust uptakes while offering good damage control. This arrangement is possible thanks to the flexibility of IFEP and propulsion pods. Battery’s and several large diesel generators will provide emergency power if the prime movers fail for any reason.

As always the final design is a compromise of competing design pressures and national priorities. Incidently given that the French have been on again/off again about buying into the CVF program for thier second carrier does that mean you’ll automatically change your opinion if they decide to go for it:)

Daniel

Without taking sides here? (Which, is hard….because I love a good debate!) I have noticed that the island (i.e. singles) of many of the newer Carriers seems to be getting bigger? Case in point the CdG island seems to be proportionaly larger than say the earlier Foch? What’s up with that?

I’m sorry….but your arguments make no sense……..ALL necessary functions can be combined in a single island….this has been the choice for over 60 years…….an aircraft carrier should have maximum unencumbered deck space devoted to aviation……..by its very nature a carrier will be vulnerable to damage……..its the trade off for efficiency in aircraft operations…….and until the US Navy or Marine National adopt this “two island” concept, I’ll stand by my argument for a single one. Sorry if my not accepting your viewpoint offends you, but I’m actuly quit flattered that my opinion means so much to you.

Also is I could add to this. The contention that islands them selves waste deck space and all thier spaces could be placed below overlooks the fact that doing that removes valuable hangar, magazine or bunkerage space. If you remove too much of that then your deck space is wasted anyway since you don’t have the assets and resources to utilise it.

Daniel

It is…….US Navy has more carrier experience than any other navy on Earth…….and they would NEVER split the island………..it is an unnessasary seperation that simply adds to the complexity of the design and makes flight operations that much harder……..There is a reason US, French, and (up to this point) British carriers have only had one island….ITS THE BEST SOLUTION.

TWO islands are a waste……..one is perfectly adequate……..

If you’ld bothered to look at some of the imagery on Beedal’s website instead of just repeating your opinion in spite of reasonable explanations of why the island IS split, then you’ld have see that it is NOT a wast of deckspace. The islands take up just as much deckspace as a single island (which, as you can see from the artistry, would be much larger). Splitting the island has the advantage mentioned wrt the locations of funnels and airducts to and from the engine rooms. Also, a twin island improves airflow over the deck. Finally, it allows for seperations of ship control (forward isle) and flight control (aft island) while building in redundancy (each island could take over functions from the other if that where hit). Therefor, it is NOT a waste of space.

TWO islands are a waste……..one is perfectly adequate……..

On the surface that sounds reasonable……Yet, the US and Japanese Navy’s tried Islandless Aircraft Carriers in the 30’s and 40’s only dropped the idea altogether…….

Again…..its a horrible waste of valuable flight deck space……

Both, the engine rooms are widely spaced and the 2 island design allows for the minimum amount of air/exhaust ducting to each engine room.
Richard Beedall’s site is the place to go for CVF info http://frn.beedall.com/cvf1-13.htm

So, the exhaust funnels are in both forward and aft islands?

Foward or Aft Island?

Both, the engine rooms are widely spaced and the 2 island design allows for the minimum amount of air/exhaust ducting to each engine room.
Richard Beedall’s site is the place to go for CVF info http://frn.beedall.com/cvf1-13.htm

They house the funnels for the engines too.

Foward or Aft Island?

Why the twin islands on the CVF design? Seems like a horrible waste of deck space to me…………

They house the funnels for the engines too.

Why the twin islands on the CVF design? Seems like a horrible waste of deck space to me…………

I think some of it has to do with elevator placement. Further, many like the bridge placed foward for easyer ship navigation. While the bridge placed aft is better for flight operations. Thus the unusual compromise………….at least thats my understanding :rolleyes:

I think Scooter intends the cheap DDH to have no offensive armament or systems, only defensive ones.

The helicopters are the offensive weapon system.

Yes, thats true……futher the DDH would be protected by the Carrier and its screening escorts. (i.e. Cruisers, Destroyers, and Frigates) The same could be said for Transports and Amphibious Ships. The only difference is the DDH would be fast enough to keep up with the Carrier Battle Groups 😀

Why the twin islands on the CVF design? Seems like a horrible waste of deck space to me…………

I think Scooter intends the cheap DDH to have no offensive armament or systems, only defensive ones.

The helicopters are the offensive weapon system.

A ‘cheap’ DDH is hard to image. A normal DD with the standard ASW & AAW fit (sensors, tactical data system, etc) is already a pricey item. Expand this to include more aviation assets and the cost increases.
Since a DDH would be by definition a combatant and would be subject to battle damage it would have to be built to naval standards with all the associated redundancy.
The ideal DDH would include the normal DD outfit along with the capacity to operate mulitiple rotary wing a/c and UAV’s.
(some possible examples: the Japanese DDH or the proposed DDH variant of the Spruance DD’s)