Cheap Scottish Ferries - But Is there a Catch? 

Catch. They always breakdown

CalMac is wholly owned by the Scottish Government via their wholly owned management company Caledonian Maritime Assets Ltd (CMAL).

Drink flat coke before hand, as it breaks up the acid in your stomach. Tried and tested as an Ex seafarer..

Obviously not a happy traveller. Best avoid the West Highlands. Last time I took a ferry from Dover to Calais there was vomit everywhere due to the heaving of the vessel. The ferries are 'cheap' as you put it because of road tariff equivalent subsidy to mimit the disadvantage to the islands. Cheap make it sound like ramshackle ships.