I have cycled past it dozens of times and never noticed it - I finally saw it.
Fastened to the fence in a place that nobody is ever going to see it between the CalMac ferry terminal and where the fishing boats berth is a rather useful sign about navigation in Oban Bay and around the north end of Kerrera.
Worth a look - and just in case you don`t know - around this area CalMac ferries have the absolute right of way - sea kayaks and sailing boats need to get out of their way. CalMac ferries have very loud horns !