The harbour is at Scrabster. Brilliant fishermens cafe, do big smoked kippers from about 6am each morning
Harbour huge and well protected, needs to be up there. Lots of ferries to the islands. Slipway has a bend at the top but wasn't a problem. B&Bs busy on Friday / Sat nights as they cater for divers going to Scapa Flow in the Orkneys. You should chat with the harbour master about petrol, might have to be delivered for the quantity you will need. Presumably you will claim the tax back as you will be exporting it.