Video: Why Queen Elizabeth Carriers Have Twin Islands?

Video: Why Queen Elizabeth Carriers Have Twin Islands?

 

queen elizabeth twin islands 

 

The newest British aircraft carriers are the first ever to have a twin island design, but why did the British Navy come up with a design like that? Well, the answer can only be found below the deck, in the Engine room.

To be precise, there are two engine rooms on the Queen Elizabeth class carriers and they are spaced apart in order to increase redundancy and survivability. During World War II, HMS Arc Royal was lost to a single torpedo hit, which caused flooding in the Engine room. For this reason HMS Queen Elizabeth and HMS Prince of Wales have two propulsion systems which are separated. So in case one is compromised, the other can still function.

But this creates a problem as propulsion systems need their own set of exhaust shafts and down takes. The gas turbine exhaust pipe is 2.4 meters in diameter and it can’t be easily bent, meaning that the shaft has to be pretty much on top of the engine room. Since the down takes and the exhaust pipes are hidden within the islands’ megastructure, it means that the newest British carriers could either have one long island, just like the invincible class carriers or two smaller islands.

British engineers conducted a thorough analysis to pick which design is better and since we already know the outcome we will discuss the five advantages of having a twin island design and one major disadvantage.

The first advantage is that two smaller islands have less footprint than the one bigger island, the space between the two islands can be used to install an aircraft lift, which is a much better use of space.

The second advantage is reduced air turbulence on the flight deck. Turbulent air is a major obstacle in flight operations and having less of it is always a good thing.

The third advantage is increased for both ship operations and the flight control. Having a front island more forward to the bow of the boat results in better visibility for the crew on the bridge, especially in tighter waters. Traditionally, flight control also known as Flyco is just an appendix section of the bridge, but with a second island dedicated to Flyco, you can position it at an optimal location towards the stern of the carrier as that is where the planes land. The Flyco tower has a 290 degree of the flight deck through giant three meter tall windows, having such a view simplifies things and increases aircraft controllers awareness as they talk through the landing procedures with the pilots.

The fourth advantage is that the twin island design allows for better separation for the main radars. Since having two sets of radars on two separate islands decreases signal interference and blind spots.

The fifth and final advantage of having twin islands is that they can be constructed off-site as separate units and then installed into the hull. This is much easier than building one large island made of many modules.

But what about the disadvantages? Well, the biggest disadvantage actually seems to be the physical separation itself. The front island is primarily used for ship control and the island towards the back is used for flyco for flying control. Since launching and landing aircrafts from a moving ship is a delicate process, it means that the ship control and flying control need to be in constant communications as the ship’s heading and speed must be precise during launches and landing. Having ship control officers and flight control officers work together in close proximity simplifies things, so now having them on different islands means that they have to rely on intercom for their communications. This is something that will take some time to get used to.

That said, in case one of the islands is compromised, the second one can assume its functions and vice versa. If intercom breaks, even though not ideal, everything can still be run from one of the islands.

So, What’s your take on this twin island design? While you think about it, here is an interesting video explaining the twin island design of the Elizabeth Carriers! 

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