backbay stripers

Greetings;
I was wondering if anyone could recommend how to catch
ocean stripers in 47 - 50 degree water. I know that around
here (Long Island, NY) they usually hang out around obstructions
in the water, but I having a hell of a time getting them.

I usually fish in an area by a bridge, around 15 - 25 feet
deep. Chum and clam bellies seem to work well around here.
Question is, when fishing for them do you set the chum up
to drift on top of the water from the boat and let your clam belly
out (naturally sinking), or would you put the chum on the
bottom and use a weight on your line to but the belly on
the bottom (usually I would bounce the line out from there
so it would look more alive)

Ok, I know this is a crappy description, but I really need some
help here!!! The areas I generally fish in are inlets coming from
the ocean....

Suggestions?

Thanx.
Tom