I regularly use this route, Roger, in preference to the long drag round the road. It's not too much more expensive, given that you save something on fuel, and can be done in roughly the same time as the full road trip if you time the connections right. You're roughly 40-50 minutes Glasgow to Gourock, 20 minutes across to Hunters Quay, 40-45 minutes from there to Portavadie, another 20 minute ferry crossing, and then 40-45 minutes from Tarbert to the town. I find it a much more stress-free way of getting to and from the city. A wee tip if you do go by the ferries - buy your Western Ferry tickets in Greenock (the wee Co-op on Eldon Street, the main road out) or in Gourock (Danny's Food & Wine on Kempock Street). It's very much cheaper than buying them on the ferry. At the Dunoon end you can get the tickets at the small mini-market/post office at Sandbank).