its side on a sandbank midway between Greenock and Helensburgh, forming a large shipwreck which is still visible in the middle of the Firth. Though the sugar trade has been greatly reduced, Greenock's Ocean Terminal facility now handles container freight and regular cruise-liner traffic. The Royal Navy HMNB Clyde bases on Gare Loch and on Loch Long are linked by this area of the Clyde, and the Greenock Great Harbour is one of the three main ports providing marine services support to the Navy, formerly under the Royal Maritime Auxiliary Service and currently operated by Serco Denholm. "Admiralty boats" are therefore a common sight, occasionally shepherding large Navy ships. References External links Burns, John Allen, Heroes of the British Merchant Fleet The Clyde's Wreck - Captayannis, the "sugar boat" Estuaries of Scotland Landforms of Argyll and Bute Cowal Firth of Clyde River Clyde Scottish coast