P&O Ferry services between Ireland and UK.
P&O operate the Norbank and Norbay superferries across the Irish Sea between Liverpool and Dublin Port, with a crossing time of about 8 hours.
P&O also operate ferry services betwee Larne in Northern Ireland and Troon or Cairnryan in Scotland. The Express takes about an hour to cross between Larne and Cairnryan. Alternatively the Superferry has a crossing time of 2 hours.
P&O also offer a 2 hour Troon-Larne service that operates between March and October, ( Troon is about 35 minutes from Glasgow)