T-Bone...
Although I can't help you with prawning right in the sound I could help you out with your shopping list.
Traps - round ones!! Depending on your storage area aboard it may dictate if you want something you can fold right up and collapse or just something that you can stack. I like the stacking ones but when we head away for quite some time on the boat we tend to take collapsible.
Line - You probably want to have a good 400' of line attached to your trap. If you have some extra for the depth you are in the weight on your line will account for that so it is not strung out along the surface.
Float(s) - It has to be labelled very clearly with your name and phone number on it.
Weights - you may want to buy a weight for your line which you attach below your float to ensure it hangs straight down below the float. (this prevents it from sitting on the surface and getting caught up in props/keels etc. Depending on the current etc you may want to weight your traps with a few pounds of weight (will be able to buy with the traps) as it will keep your trap from drifting with tides/current/winds.
Bait - utilize the pellets that you can buy in most stores. If you can find a fish processing plant or a place to get fish oil I like to mix it in with the pellets in a ice cream bucket.
Bait Cups - these are the cups that hang in your traps and where you keep your bait "concoction".
As for "where"....well generally you want to be in at least 275' water but we tend to target in the 300-350 range. Hopefully someone from that side of the island will be able to help you out a bit more. I tend to do my prawning up the "inside passage" and closer to Vancouver and the Georgia Strait.
Just typed this quickly and I am sure I may have missed something that others will type in but that is pretty much your "basics" for getting started.
Do a search on this forum and I am sure you will find plenty of information on prawning. As a matter of fact there was one thread not too long ago that had a great list of what you need and what you need to "know" to do it.
Maybe someone else can recall, but just search "prawns" or "prawning" and it should bring up some info.
Oh....and welcome to the forum.
Just found this....which may help.
http://www.sportfishingbc.com/forum/topic.asp?TOPIC_ID=9552&SearchTerms=prawning
Some good info in this one as well.
http://www.sportfishingbc.com/forum/topic.asp?TOPIC_ID=9478&whichpage=2&SearchTerms=prawns