Hi Soto,
I think the most dangerous thing in the water will be your foil !

The only things you'll have to look out for once you get out to the 'blue line' is speeding jetskis every now and then, or boats (more common in summer).
The only distance/speed regulation that may apply is the same one for boats - 4 knots within 50m of jetty or swimmers or diver flag - but I'd be surprised if this has ever been enforced on any windsurfer or kite surfer.
And in short - you may only need to wear a Level 50 PFD.
(Marine safety have recently checked windsurfers at Boggy Lake, Middleton, Goolwa.)
The safety equipment you must carry depends on where you operate, definitions for South Australia are...
PROTECTED WATERS - All inland waters except Lake Alexandrina, Lake Albert and waters influenced by the tide.
SEMI PROTECTED WATERS - Waters inshore of a line 2 nautical miles to seaward of the low water mark of the coast of the mainland or Kangaroo Island, or the banks of Lakes Alexandrina and Albert. Tidal waterways such as the Port Adelaide River and the Coorong are classified as semi-protected waters.
UNPROTECTED WATERS - Waters offshore of a line 2 nautical miles seaword of the low water mark of the coast of the mainland and Kangaroo Island, or the banks of Lakes Alexandrina and Albert.
Sailboards or kiteboards category PFD regulation:PROTECTED WATERS - must wear: Level 100 or Above
OR Level 50
OR Level 50S
SEMI PROTECTED WATERS (when less than 400 metres from shore) must wear: Level 100 or Above OR Level 50 OR Level 50SSEMI PROTECTED WATERS (when greater than 400 metres from shore) must wear: Level 100 or Above
UNPROTECTED WATERS - all must wear: Level 100 or Above
Download the full SA Boating Safety Handbook...
www.sa.gov.au/__data/assets/pdf_file/0010/11701/SA_boating_handbook_Sept_2018_WEB.pdfTips:
Avoid sailing close to the River Torrens outlet after heavy rains - it will flush out to sea and the water will get very brown and stinky and probably not good for your health. Also the river Carp get washed out to sea, die and smaller sharks come in to feed on them, but they aren't a problem and are rarely seen.