The jet-ski escapee is Chinese rights activist Kwon Pyong. He had posted pictures on social media mocking Chinese President Xi Jinping, and spent time in jail in China for subversion.
South Korea's coastguard said Tuesday it had arrested a Chinese national who tried to enter the country after travelling by jet ski from China -- a journey of more than 300 kilometres (186 miles).
Wearing a life vest and helmet, the man crossed the Yellow Sea on a 1800-cc jet ski from Shandong province, using binoculars and a compass to navigate and towing five barrels of fuel.
"He refilled the petrol on the ride and dumped the empty barrels into the sea," the coastguard said in a press release.
Looking at it on a map it looks like it's a huge bay, enclosed on 3 sides. I doubt there would be any significant "swell". There might be small waves whipped up on a windy day but barely enough to trouble you on a jet ski particularly if you're moving.
The main risk would be exposure. Too hot, too cold or too much sun even on a cold day can really fuck you up.
I've sailed there, granted it was on a merchant ship, and it varies a lot. If it's little or no wind or a slight breeze from the west he would be fine weatherwise but when we had a small storm pass through it was a bit rough even on a 200m ship. Would look carefully on the weather report before attempting this, especially since he was towing his fuel.