I don't know if you have checked this site out, but it provides an interesting view of the waters around Australia. You need to hone in on the particular spot you want to look at using the arrows and the focussing tools and then click on the satellite button at the top right hand side of the page. Good tool for looking for reefs and things, though the image is not up to date, so not so good for looking for sand banks and such

http://maps.google.com.au/maps


Regards Colin Hay