Fishermen sometimes happen upon submarine accidents. This one dates from 2003:
On April 25, 2003 the crew of a Chinese fishing boat noticed a strange sight—a periscope drifting listlessly above the surface of the water. The fishermen notified the People's Liberation Army Navy (PLAN) which promptly dispatched two vessels to investigate.
On April 25, 2003 the crew of a Chinese fishing boat noticed a strange sight—a periscope drifting listlessly above the surface of the water. The fishermen notified the People's Liberation Army Navy (PLAN) which promptly dispatched two vessels to investigate.
https://www.chieftain.com/story/news/2018/06/07/in-2003-chin...
Every one of the submariners died.
There was another reported Chinese sub accident in 2023, but it's not clear how it was discovered (https://www.rfa.org/english/news/china/china-submarine-death...).