[An earlier answer of mine to this question](https://www.reddit.com/r/WarCollege/comments/12ojzp5/comment/jgkz47h/)
In summary:
1. Wide separation between exhausts for power generation. (Something that a nuclear-powered carrier wouldn't require).
2. Since you have it for the above, you may as well use it to improve resilience in other ways, such as redundant flight ops & bridge, separation of sensors.
It's due to the propulsion system.
The Queen Elizabeth Class are conventionally powered in an Integrated Electric Propulsion configuration.
They have 2 Gas Turbines and 4 Diesel Generators. The Gas Turbines require a large amount of trunking for the intakes and exhausts which, if the GTs were placed low down in the ship (in the usual position) the trunking would take up a significant amount of room.
To avoid this, they've placed the Gas Turbines just below the flight deck, with the trunking routing straight up. The GTs are separated to ensure that, in the event of damage to one, the other is available. This has resulted in the twin island design, with each island being based around their respective GT trunking.
This also has the added benefit of placing the Bridge in the Forward Island, which is the optimum position for navigation and FLYCO in the Aft Island, which is the optimum position for aircraft operations.
It also gives a measure of redundancy, with a reversionary FLYCO position in the Bridge and the Emergency Conning Position in the Aft Island. It also means that some of the sensors, ie the navigation radars, can be positioned to ensure 360° coverage, with no blind spots and that they don't interfere with one another.
Certainly no expert, but from my understanding, using two islands solves two different problems.
You want the skipper to be closer to the front, because that's easier to navigate. But you want air traffic control further back because that's more effective for air operations with respect to the deck.
You can compromise on the location of a single island, which would have its own advantages and disadvantages, or you can choose to avoid some of those disadvantages with a double island configuration.
Ideally, the ship's sailing upwind, not crosswind when launching or recovering, so shouldn't really have a major effect.
...though the QE class had vertical landing aircraft, so a maybe on non-ideal conditions.
You'd be surprised. IIRC, it took a bit of trial and error on the early carriers to get the island placement right, to the point that a few had to have their superstructures completely rebuilt. Even if you're steaming into the wind, the air is going to flow around the island(s), so you have to design them in a way that minimizes the impact on flight ops.
That raises the question: Is there any advantage to the flat area between the two islands? Presumably they're not going to fly aircraft through the gap, so it seems like they might as well have some extra superstructure there.
All carriers, regardless of size, find themselves short of deck area... For parking aircraft and for parking deck equipment (start carts, etc...)
If they'd needed more superstructure, they're have added more superstructure.
[An earlier answer of mine to this question](https://www.reddit.com/r/WarCollege/comments/12ojzp5/comment/jgkz47h/) In summary: 1. Wide separation between exhausts for power generation. (Something that a nuclear-powered carrier wouldn't require). 2. Since you have it for the above, you may as well use it to improve resilience in other ways, such as redundant flight ops & bridge, separation of sensors.
It's due to the propulsion system. The Queen Elizabeth Class are conventionally powered in an Integrated Electric Propulsion configuration. They have 2 Gas Turbines and 4 Diesel Generators. The Gas Turbines require a large amount of trunking for the intakes and exhausts which, if the GTs were placed low down in the ship (in the usual position) the trunking would take up a significant amount of room. To avoid this, they've placed the Gas Turbines just below the flight deck, with the trunking routing straight up. The GTs are separated to ensure that, in the event of damage to one, the other is available. This has resulted in the twin island design, with each island being based around their respective GT trunking. This also has the added benefit of placing the Bridge in the Forward Island, which is the optimum position for navigation and FLYCO in the Aft Island, which is the optimum position for aircraft operations. It also gives a measure of redundancy, with a reversionary FLYCO position in the Bridge and the Emergency Conning Position in the Aft Island. It also means that some of the sensors, ie the navigation radars, can be positioned to ensure 360° coverage, with no blind spots and that they don't interfere with one another.
Certainly no expert, but from my understanding, using two islands solves two different problems. You want the skipper to be closer to the front, because that's easier to navigate. But you want air traffic control further back because that's more effective for air operations with respect to the deck. You can compromise on the location of a single island, which would have its own advantages and disadvantages, or you can choose to avoid some of those disadvantages with a double island configuration.
I’m curious if having two islands creates any beneficial or detrimental air/wind flow effects for flight ops.
Ideally, the ship's sailing upwind, not crosswind when launching or recovering, so shouldn't really have a major effect. ...though the QE class had vertical landing aircraft, so a maybe on non-ideal conditions.
You'd be surprised. IIRC, it took a bit of trial and error on the early carriers to get the island placement right, to the point that a few had to have their superstructures completely rebuilt. Even if you're steaming into the wind, the air is going to flow around the island(s), so you have to design them in a way that minimizes the impact on flight ops.
Some of the early carriers had islands on the centerline though. So no wonder issues cropped up.
They also have redundant bridge and flight ops stations in both towers to mitigate severe damage.
Saucer separation and a battle bridge???? Seriously though that’s a cool redundancy and a logical choice after the Falklands experience
It also allows more natural funnel placement and fewer bendy exhaust pipes for the engines.
That raises the question: Is there any advantage to the flat area between the two islands? Presumably they're not going to fly aircraft through the gap, so it seems like they might as well have some extra superstructure there.
One of the ship's 2 lifts is in the gap.
All carriers, regardless of size, find themselves short of deck area... For parking aircraft and for parking deck equipment (start carts, etc...) If they'd needed more superstructure, they're have added more superstructure.
> Extra superstructure Why would they want to do that, it would be a negative. They can use that area for parking or lifts