Possible to build a modern submarine aircraft carrier?, page 2

Is building a submarine aircraft carrier possible? Sure. You mention the Japanese I-400's in the original post, so it's obviously possible. The real question is "Is building a submarine aircraft carrier practical, and does it offer advantages over its conventional kin?".

First, let's look at practicality.
A submarine aircraft carrier is going to need (relatively) huge openings in its pressure hull in order to move planes from inside to outside, to onload and offload stores, etc. Big openings need big hatches to seal them, and that means big gaskets to make sure that the hatches are water tight. Even worse, there are going to be a *lot* of these hatches, unless you're planning on launching one aircraft at a time (which makes strike coordination very difficult), and they're going to be opening and closing frequently. All of that adds up to a serious chance of seal failure, which leads to flooding. Any flooding in a sub is bad, but flooding an area the size of an aircraft carrier's hangar deck is fatal.

Even if the hatch seals hold up, every opening in the pressure hull robs the hull of a bit of strength. By the time you have enough hatches to support aircraft operations, you're going to be extremely limited in your ability to dive, and in the depth to which you can dive without risking hull damage.

Then there's the communications problem. How does the submerged carrier communicate with its air wing, or with other naval and / or shore-side forces?

Assuming we can solve the construction problems, and the communications problems, let's look at the advantages and disadvantages vs a conventional carrier.

Advantages
Difficult for the enemy to detect.

Coolness factor.

Disadvantages
Cost. I don't know *how* much more expensive a submarine carrier will be than its conventional counterpart, but based on recent experience, and assuming that the ships are equally capable in terms of air wing, a five-fold price jump doesn't seem a huge stretch.

Limited air wing. You've probably noticed that most U.S. carriers almost always have aircraft on deck, parked along the edges? Deck spotting like that allows you to carry more planes on a smaller hull. A submarine carrier can't deck spot, and so will be limited to a smaller air wing.

Vulnerability. It's not easy to sink a conventional aircraft carrier. It's not that hard to mission-kill one by holing a flight deck, or destroying radars and radio systems, but actually destroying one takes some serious beating-on. I'll direct your attention to the massive fires aboard USS Forrestal and USS Enterprise for supporting data. A submarine carrier is literally vulnerable to a 'one shot, one kill' solution. It would have much less ability to survive damage.

Loss of mission capability. The one advantage a submarine carrier would have would be its ability to remain unseen...until it starts operating aircraft, at which time, it must come to the surface. Since a carrier in combat is launching / recovering aircraft on a 24/7 basis, a submarine carrier will be forced to either cut back on its ability to perform its missions, or give up its sole advantage by staying on the surface for most of its time in comba.

Loss of performance. There's a reason that submarines aren't shaped like conventional ships. Hull form has massive impact on speed, maneuverability, and quietness in an underwater environment. Unfortunately, the hull forms that make for good performance as a submarine don't allow much in the way of aircraft operations, and hulls that lend themselves well to air ops make for really noisy submarines.

Adding it all up, my conclusion is that we could build a submarine aircraft carrier...but we'd probably get better value for money spent by building a submarine, and an aircraft carrier, on seperate hulls.