When I read The Drive's July 20, 2021 article :
The [USN] Is Looking At Fitting Its Future Attack Submarines With Inflatable Sails
I checked that it was not a late entry for April 1st (Fools Day).
The inflatable nature "sail" or "fin" (what used to be called a "conning tour") involves immediate and possible problems, many and varied.
1. The article rightly comments a fin "has an important function of breaking through the ice and providing initial access outside of the sub when operating in polar regions."
So I ask: would the lack of a rigid sail require instead a separate ice piercing spike to penetrate the ice?
This is especially if there is a need for emergency surfacing - say a US SSN, while under the ice, was damaged by a Russian or Chinese torpedo?
Or what if the reactor needed an emergency shut down while under the ice (in peace or war)?
Even if a spike breaks through the ice and the sail is then inflated polar bears (I kid you not) are known to try to attack parts of surfaced SSNs. Might a hard bear bite deflate the sail?
2. The article also rightly comments: "Above all else, the sail is normally used to house important sensors like periscopes, communication antenna masts, as well as electromagnetic and radar sensor systems."
So how could the various optronic (aka photonic) masts and antennas penetrate a damaged, hence un-inflatable or improperly deflated, sail?
Also the sail might need to be inflated while the sub is submerged (running shallow) if the sub's Captain wanted to deploy his 360 degree search mast or attack mast to peak just above the surface?
3. The inflatable sail would need to be very rigid indeed to remain rigid in high winds and rough seas, particularly when the captain (and up to 4 crew) are standing on top of the sail when the sub is exiting or entering the port area. I understand the approaches to US mainland bases, US overseas sub bases and the UK Clyde/Faslane base can experience very rough swells. Might a flexible mast bend the Captain and watch members into the sea?
How could you safely/efficiently deflate a sail for stowage in high winds and rough seas?
4. Fortunately the article also raises "ballistic protection against small arms fire."
Even short of foreign country naval threats, might a nutter, terrorist or smuggler with a US$200 light machinegun cause enough damage to deflate the sail, thus crippling a US$5 Billion SSN(X)?
In the end.
5. Once a sail is damage and deflated would it be easily stowable so the sub can efficiently dive and continue efficienctly and safely on its mission?
Can anyone think of any other pitfalls of inflatable/deflatable sails?