The Tail of the Bank is the name given to the anchorage in the upper Firth of Clyde immediately North of Greenock, between Inverclyde and Argyll and Bute. This area of the Firth gets its name from the deep water immediately to the west of the sandbank which marks the entrance to the navigable channel up the Estuary of the River Clyde. Location From the Glasgow Green Tidal Weir westwards, the River Clyde is tidal, mixing fresh and salt water. At Milton Island the river was still shallow, then past Dumbarton and the confluence with the River Leven a shoal and sandbank increasingly takes up most of the width of the estuary and extends along the north shore for about to Ardmore. Areas of sandbank dry out at low tide, including the Pillar Bank off Dumbarton and Cardross. By Port Glasgow the main flow of the river is close to the south shore, with the Cockle Bank to its north, then the Greenock Bank which extends past the waterfront harbours to a point off Ocean Terminal where the "Tail of the Bank" shelves steeply down to exceed depth. The Shoals at this depth extend northeasterly towards Ardmore, then meet a shallow slope off the northern shore. The depth continues to the northwest, and about midway across the firth between Ocean Terminal and Craigendoran is marked by the wreck of the "sugar boat" Captayannis which lies in that depth about north of Greenock Esplanade. To the west of Helensburgh, a deep channel enters the Gare Loch. On its west, the Rosneath peninsula forms the north shore, across the firth from the Fort Matilda suburb of Greenock. Midway between them, the Rosneath Patch reef divides the Clyde into two deep-water channels, and sets the west boundary of the anchorage. Ships approaching up the Firth of Clyde can take the Ardmore Channel along the south shore of the Rosneath Peninsula, turning north up into the Gare Loch, or the main Firth of Clyde Channel which follows the Greenock shore east-southeast to Ocean Terminal. The entrance to the dredged channel of the River Clyde is between No. 1 green conical light buoy, off Greenock Esplanade in line with Margaret Street, and No. 2 red can light buoy marking the Tail of the Bank, about from the corner of Princes Pier. The channel continues about to the centre of Glasgow. The anchorage depth varies from