Your boat is plenty to get you to broughton island but offshore boating is about confidence and experience. If you tried trolling the islands out the front of the heads would be a good start. Plenty of snapper and kings about up broughton. Best spots, sisters, north rock and cod rock. Live bait at cabbage tree n/w corner.
The bay itself, try the wreck at corlette or steps at fame cove for jew. The breakwall early morning for kings. Flatty at any of the beaches on the eastern side of soldiers in 3-5m water. Look for the drop offs.
If you do go to broughton, look for a 1.2m or less swell and 10knots or less wind. In the summer afternoons the nor'easter really kicks in so it will be on your tail on the way home.
Hope that helps.
Cheers scratchie!!!