Guys ,
is very tide dependant down the Queenscliff end. There are sandbars everywhere which you can sail over on higher tides but become very shallow on lower tides (even exposed - which is great for speedsailing - Jacques hitting 40 knots here) You can launch half way up swan bay at the end of swan bay rd (boat ramp & Jetty) but you will have to walk through some mud to get out. Here is is much deeper as you sail in the main channels.
There was some rumours years ago of lots of blue ringed octopus around but have spoken to marine biologist at Queenscliff and he reckons no more than anywhere else in the bay. Still makes me wear booties though..
Hope this helps..