China/Iran/Isreal/Russia (i could name a more few) all have the ability to do this, maybe even undetected.
Analysis of the detonation device used will be hard for a ship sunk to 3000 feet, not sayin this is impossible.
A carrier group can only do so much in the end.
Analysts pointed out the same issues in 1985. The Backfire bomber was the crisis then.
“Building aircraft carriers is a symbol of an important nation. It is very necessary,” the China Daily paper quoted Admiral Hu Yanlin as saying earlier this month. “China has the capability to build aircraft carriers and should do so,” he said.
If you’re used to reading through DoD propaganda, no matter what country it’s coming from, you see what the admiral is saying here. Here’s my loose translation of what Admiral Hu is getting at: “We don’t actually need a carrier, but it’s part of being one of the big boys so we have to do it, like paying for your kid’s wedding. So we’ll turn out a few of them, but we’re only going to do it when it’s cheap and doesn’t interfere with production of real weapons like the DF-21.”
http://exiledonline.com/war-nerd-china-joins-the-yacht-club/
So long as air power will play a significant part in warfare platforms to bring airpower where ever needed too will play a part.
If we are talking about a potential South China Sea conflict, then it's all in range of Chinese planes flying off Hainan.
If we are talking more broadly, then I think you'll find that the Chinese idea of world power does not involve force projection the way the US understands it.
[0] https://en.wikipedia.org/wiki/Aircraft_carrier#China
[1] https://en.wikipedia.org/wiki/Chinese_aircraft_carrier_Liaon...
One would note that India spent $2.3 Billion on INS Vikramaditya[1], which was also an ex-Soviet aircraft carrier, of roughly similar vintage. It was fitted out though, so the comparison isn't entirely fair.
Nevertheless.. $20M vs $2.3B
China may have catamaran missile boats and Sovremmry destroyers, but guess what? Those ships won't be operating far from Chinese coastal waters. Those "obsolete" carrier battle groups can operate virtually anywhere on the coast of any ocean. And they'll be able to deploy whatever mix of manned and unmanned aircraft they need to.