Simon Worrall sets sail for a southern island to meet a man fighting the looters of China's underwater treasure.
It isn't easy getting to Hailing Island. As ever in China, there is the language barrier.
I have been told to head for Yanjiang, a provincial city about three hours south-west of Guangzhou, or Can ton, as it used to be. But the receptionist at my hotel hears the name of the city as Zhangjiang. Finally, after much poring over maps, we get the right place...
I am not here for a holiday, though. I have come to meet a man called Zhang Wei, head of China's marine archaeology unit. An energetic man of 52 with a winning smile and a mop of black hair, he drives an Audi and dresses in smart western clothes.
Dangling from a silver chain under his pink cotton shirt is a chunk of jade worth more than £1,000. His cellphone rings incessantly.
"We estimate that there are 2,000 ancient shipwrecks in the territorial waters of China," he says, as we sit drinking "Kungfu" tea from thimble-sized cups at the marine archaeology unit's base, which doubles as a hotel.
In a classroom below us, a group of students, including two from Kenya, pore over barometric tables. Through the window, we can see brightly painted fishing boats bobbing on the waves.
"We have identified more than a hundred sites off the coast of Guangdong and Fujian alone."