Minimum...
-Life Jacket
-Harness
-PLB
-Strobe
Extras...
-auto inflatable life jacket
-smartphone with waterproof case
-MOB AIS/SART transmitter

This one of the reason I bought a local boat as I nearly bought a boat in Sydney, but did not have the time to make sure the boat would be sea worthy enough to make it back to port Philip bay and also the preparation that I think is needed .
It may be different for others but Ive been mainly a dinghy sailor and some charters I may have over looked some thing and made a mistake from my inexperience.
Yes it is a shame this happened as Sir Jman has said I would not go out there with out those .
But for me personally I like to know any machinery I am going to use no matter what it is Bike car or boat
Its a real shame this happend