StarDestroyer.Net BBS

Got idea from here This vessel has a lot more deck area than Nimitz class carriers. An aircraft carrier using similar catamaran design could have a lot more room for aircraft and potentially be faster too like catamaran ferries that can go over 40 knots. It could have huge hangar deck below flight deck spanning entire ship. One hull could have runway dedicated for landing and other hull for takeoff so the entire length of the ship can be used potentially allowing to operate heavier more capable aircraft. Superstructure island and aircraft parking area maybe located in the middle.


Certainly there must be a good reasons why such carrier aren't built. Is this because existing designs are good enough and well proven and no one wants to risk several billions of dollars to try out unproven design?

The catamaran design would make for a more stable platform for launching and recovering aircraft, and the centrally-located island wouldn't obstruct flight ops. Also, with angled flight decks on both hulls, you'd be able to launch and recover more aircraft.

The catapult system would be complicated, even if you use separate catapults for both decks, and you'd only be able to build one carrier for the price of two "regular" fleet carriers.

U.P. Cinnabar wrote:The catapult system would be complicated, even if you use separate catapults for both decks, and you'd only be able to build one carrier for the price of two "regular" fleet carriers.

It definitely wouldn't be twice the price, even if it is actually twice the displacement; steel is cheap. A lot of systems e.g. electronics and self-defence suites would still be the same size and cost. The number of elevators and catapults might be a bit higher but not double. Ditto for the machinery spaces.

Last time I asked about this (for destroyers) the main reasons were lack of suitable drydocks, and until recently lack of adequate hydrodynamic understanding to optimise the hull forms.

The limiting factor to aircraft carrier compliments was newer deck size but command and control. And this was newer as true as it is today when massed air raids and constant flight screens have been replaced by precision strikes. The reason why nobody is building multihull giant megacarriers that can fit 200+ sized air wings is because you can't coordinate that amount of aircraft effectively. And even if you could you would have no need for it. Ultimately using that money and material to build two separate carriers that can be in two different places at once proves to be the superior option.

Off the top of my head, such a carrier probably wouldn't fit through the Panama Canal, which is a serious problem if the U.S. is going to be building this. Also, existing carriers are nearly never filled to capacity; why double a fighter complement you're not really using as-is?

There's also the issue of all the internal volume, (which is used for ship's systems, crew, supplies, etc), that'd be lost by splitting up the hull. You'd also have more external surface area to have to worry about maintaining.

Esquire wrote:Off the top of my head, such a carrier probably wouldn't fit through the Panama Canal, which is a serious problem if the U.S. is going to be building this.

They have not been able to do so for a very long time. The last carriers that could were the straight-deck Essexes.

Starglider wrote:

U.P. Cinnabar wrote:The catapult system would be complicated, even if you use separate catapults for both decks, and you'd only be able to build one carrier for the price of two "regular" fleet carriers.

It definitely wouldn't be twice the price, even if it is actually twice the displacement; steel is cheap. A lot of systems e.g. electronics and self-defence suites would still be the same size and cost. The number of elevators and catapults might be a bit higher but not double. Ditto for the machinery spaces.

Last time I asked about this (for destroyers) the main reasons were lack of suitable drydocks, and until recently lack of adequate hydrodynamic understanding to optimise the hull forms.

Fair enough. I'll concede that.

2x sized carriers mean 2x sized targets. In a hot war with a peer or near peer we don't actually expect for all of our carriers to survive, so for dubious cost savings of having a giant carrier is more than outwayed via distribution of capability and redundancy concerns. In combat with an inferior force, 2x sized carriers can only be in one place at a time, and we re balance our forces a lot.

Something people don't think about a lot is maintenance availabilities, and in the case of carriers nuclear overhauls. 1/3 or more of a CVNs lifespan consists of major shipyard work that puts it down hard. So if you have 12 carriers were 4 are always unavailable, that's 8 places you can be at globally. If you had the same capability in 6 carriers, that's only four places. It gets even more restrictive when you but in readiness, because whenever I train this new force I always have to tie up 2x the capability.

Would it be more practical, then, to retain the present carriers for carrier missions, and build one, maybe two or three of these catamaran carriers to fufill the role of a Joint Mobile Offshore Base? Especally, if you added well decks to the design, and enhanced its command and control capabilities.

Or would the dual-hull be too small for that role?

Purple wrote:The limiting factor to aircraft carrier compliments was newer deck size but command and control. And this was newer as true as it is today when massed air raids and constant flight screens have been replaced by precision strikes. The reason why nobody is building multihull giant megacarriers that can fit 200+ sized air wings is because you can't coordinate that amount of aircraft effectively.

Bullshit. There are plenty of facilities capable of coordinating larger numbers of aircraft; command and control is not in and of itself the problem. Other issues may arise and be significant, but "we can't keep track of 200 planes" isn't one of them. You just need twice as many staff, and computers which run twice as fast compared to computers of the 1980s.

Simon_Jester wrote:Bullshit. There are plenty of facilities capable of coordinating larger numbers of aircraft; command and control is not in and of itself the problem. Other issues may arise and be significant, but "we can't keep track of 200 planes" isn't one of them. You just need twice as many staff, and computers which run twice as fast compared to computers of the 1980s.

You either did not read my post completely or did not understand it. It's not about keeping track of them physically. You could do that in the 40's with a pair of binoculars and a notepad. The issues that arise are:
1. Coordinating takeoff and landing procedures in limited air space.
2. Coordinating reloading and refueling procedures for that number of aircraft.
3. Actually planning the sheer amount of missions that would justify using such a giant air wing.
4. Coordinating all of those missions in real time (aircraft are after all not a missile you fire and forget about) whilst doing #3 for the next round.

And last but most important actually having a mission profile that requires an air wing of that immense size being available in one place.

"Command and control" typically refers to (3) and (4) which are not a problem here.

The takeoff and landing issues are the real ones here. The massive deck space makes it reasonably practical to reload and refuel the planes, but takeoff and landing are legitimate concerns.

Then again, you didn't say "takeoff and landing" the first time around...

That's because I understand the concept of C&C to include both so I thought I did not need to. Really that seems to be our disagreement here.

]Bigger carrier may be able to operate larger and heavier aircraft which could be important if enemy has multiple hardened facilities requiring heavy bunker busters to take out. Also if carrier can be routinely resupplied with something like C 130 it would improve logistics significantly. So while larger carrier may not have more numerous aircraft it could have more capable aircraft.

biostem wrote:There's also the issue of all the internal volume, (which is used for ship's systems, crew, supplies, etc), that'd be lost by splitting up the hull. You'd also have more external surface area to have to worry about maintaining.

Not sure if internal volume would be an issue. While 2 relatively narrow hulls may have less total volume than 1 fat hull you could easily have a lot more volume in a structure holding hulls together.

One improvement would be if they had the runway length to dispose of arrestor wires and catapults. Look at the different in capability between the F-35C and F-35A. The C version weighs almost 5000 lbs more and has a significantly larger wing. As as result, it is left with a significantly lower thrust to weight ratio and inferior kinetic performance. Even the Super Hornet can likely beat it in this respect.

As a side note, it is already possible to land a C-130 on a carrier. Tests were done with the USS Forrestal in 1963. A total of 29 touch and goes, as well as 21 unassisted take offs and landings were executed. Though it was decided that the landings would be too risking to do on a regular basis. It's wings cleared the conning tower of the carrier by only 15 feet.

looks to be lower in the water then most carriers I've seen - an advantage in the next decade when naval lasers start to arrive?

If an enemy vessel has gotten close enough to hit your carrier with line-of-sight weapons, you are already sufficiently screwed that being lower in the water will not help much.

Lasers aren't going to be good as antiship weapons, honestly. Aside from the short range, they just don't carry enough raw energy density through atmosphere to match the one-time instantaneous burst of a conventional shaped-charge warhead.

It takes a lot of lasing to match the impact of a few hundred kilos of explosives plus unexpended rocket/jet fuel.

Lasers would also be more power-consumptive than existing conventional weapons systems, given current lasers' efficency at converting input power to useful output energy.

What about railguns, or do those have the same issues as lasers?

Railguns are somewhat more efficent than lasers in transferring input power to output KE for the projectile, and has the added benefit of not needing either explosive warheads or propellant, reducing the dangers traditionally associated with ammunition storage.

The main issues with railguns at the moment are erosion of the rails, heat and power needed to fire them.

Railguns will probably be the next step in the evolution of naval gunfire, following the implementation of the Advanced Gun System and the contemporaries to the AGS that doubtlessly will follow.

Lasers mostly pay off for missile defense because a laser is the only (weaponizable) thing that is faster than a missile, fast enough to track it in real time and cut it apart reliably. Also for air defense, where the targets are relatively flimsy and line of sight is long.

For surface-based targets that tend to be more rugged, and which are often obscured by clouds of dust, smoke, or fog that would greatly weaken a laser beam, shooting something with a cannon or a missile is generally better than shooting it with a (bulkier, more demanding) laser.

Railguns have major advantages as artillery weapons. The big problem is that any long range weapon capable of hitting a moving target (or even a fixed target) dozens of miles away will profit very greatly from having a guidance system. And an electromagnetic cannon that works by exerting tens or hundreds of thousands of g's of acceleration using super-intense magnetic fields to launch a projectile... that sounds like a thing that would be pretty rough on the electronics of a guidance system. Therefore, I suspect precision guided railgun rounds may be very hard if not impossible to build, especially rounds that use something like a built-in radar system or GPS receiver to target a moving object.

At some point it's easier to just fire a guided missile, especially since it's quite possible to design guided missiles that come in at hypersonic speeds just like a railgun round does anyway.

Simon_Jester wrote: At some point it's easier to just fire a guided missile, especially since it's quite possible to design guided missiles that come in at hypersonic speeds just like a railgun round does anyway.

Downside of this: Fancy hypersonic guided missiles cost money. Railgun rounds are basically just a chunk of steel (or tungsten, whatever). You can't deny there's a definite cost savings there.

Of course the guided missile would be a lot more reliable as far as hitting the target goes, but if a salvo of railgun rounds sinks the target for an eighth of the price even if not every round is on target...

EDIT: Certainly not denying that the missile would work, of course. I wouldn't be surprised to see something like that developed anyway, if it isn't already being.

Elheru Aran wrote:

Simon_Jester wrote:At some point it's easier to just fire a guided missile, especially since it's quite possible to design guided missiles that come in at hypersonic speeds just like a railgun round does anyway.

Downside of this: Fancy hypersonic guided missiles cost money. Railgun rounds are basically just a chunk of steel (or tungsten, whatever). You can't deny there's a definite cost savings there.

They're cheaper, but they're still very precisely manufactured (especially if you want them to hit the target). Moreover, you cannot afford to spam railgun rounds until one of them hits the target. Such a weapon system will have a finite rate of fire and spamming the requisite number of rounds could take hours, as opposed to minutes for a "one shot one kill" missile hit.

Also, there is the problem of barrel erosion. In real life, WWII heavy battleship guns had major restrictions on their use because the barrels wore out after a few hundred rounds and had to be replaced, which was a major job for a large repair dock. Railguns will be comparably restricted. Based on what little I've heard, it seems likely that any single ship is unlikely to be able to fire accurately at extreme range after more than a few dozen, a hundred at most, rounds fired, for the foreseeable future.

This makes it impractical to saturate an evading target with masses of 'dumb' railgun rounds. So you still need a guidance system, which drives the cost of the railgun shell back up towards the cost of the missile, and makes designing said railgun round much much more challenging.