To rent you need to be in Club or Go to the water gouverment center (weith the good paper).
For Hk Governement center (
http://www.lcsd.gov.hk/watersport/en/index.php) you need to have Hong Kong Sailing Federation level 2 to be able to rent a dinghy type Pico/Topper (Single Handed), laser 13 (double handed).
very difficult to join there training course, few seat for a lot of demand.
For the list of clubs check:
http://www.taipoboatclub.com.hk/yatch_clubs.htm
They miss
Hobie Cat Club:
http://www.hobie.com.hk/
If you are a experience sailor contact some of the club link RYHKA, Hebe Heaven, Aberden Boat Club: they all have a Crew Wanted section for different class.
If you need more info, just ask.
P.S: Sailing Saison is finishing END May for some club as no more wind in July/August.