I fished near there last year aiming for congers (conger alley). I never caught any congers but lots of doggies. I started fishing just before darkness and the water was flat calm, there was mullet everywhere and a lot of sea trout jumping. Its too early for mullet but I think it would fish well in a couple of weeks with a wee silver spinner or a strip of herring below a float.
your best bet for a few fish would probable be the caves. no caves as such just a area the divers use. normally good for wrasse, pollack and coalies to ragworm under deep fished floats. with conger and the odd doggie on the bottom at night to fish baits.
head out of arrochar towards coulport on the loch side road for approc 2 1/2 miles, you will come to a small bridge on a corner with a parkin layby. park here and head a further 50 yards down the road, theres a small pinnacle to fish from.
might be your best bet for a few fish, but you might be better heading over the rest and be thankful and fishing loch fyne...
was down a fortnight ago couple of small bites but nothing landed ,i fished wrag from the end of the caravan slip way and the missus used a spinner to deadly effect on on passers bye,was told there are miles of cables on the bottom from the old torpedo range best of luck am going back again in may,great place for relaxing regards sandy