Paddled around the grove arm wharfs tonight and got depth readings
The little one at the grove is right into a steep drop off… At around high-tide the wharf drops into 4m of water which quickly slopes away to 8m a bit further out. Then it flattens out. So casts within about 20-30m is all that is required to reach the flat.
The wharf near the start of QC track is surrounded by shallow water (1.5m). There is one piece of interest, is that diagonally from the eastern most corner runs a 3-4m deep channel.
The Thompson Bay wharf is slighter deeper but no obvious channel.
IMO the small grove wharf has the most interesting depth profile to fish.