@hike - try looking for Hillian Siu in the surfing community sites.
Another guy by the name Simon Holliday has done an even scarier trip - swimming to Macau. You might be able to find him if he is still in HK.The solo crossing will count on the support of a small team of five, who will travel nearby in a boat and offer assistance in an emergency.
Simon Holliday, a Hong Kong resident who swam the crossing between the two regions a few years back, encountered an immigration issue upon reaching his Macau beach destination.
Regarding the immigration issue, Siu said, “we are aware of the [bureaucratic] difficulties and our plan is in fact not to reach land in Macau but to jump back on the boat after reaching a defined ‘finish line’ and from there go with the crew to do a proper immigration check.”
She said that, technically, the crossing will be done by boat. “But there is nothing that says that I can’t do a watersports activity during this boat trip.”