Tizard Bank

The Tizard Bank, 10°15′N 114°30′E, in Chinese known as 郑和群礁 and Zhenghe Qunjiao, is a partially sunken atoll and one of the significant maritime features of the north-western part of the Spratly Islands. It is claimed by the China, Taiwan and Vietnam, and various parts of it are occupied by these nations.

It was named after Thomas Henry Tizard (1839 – 17 February 1924), a British oceanographer and surveyor who surveyed the bank from aboard HMS Rifleman in the 1860s. In 1947 the Republic of China government gave the bank the name Zheng He Archipelago after the famous Ming-era admiral, although there is no evidence that he ever visited Tizard Bank.

From before the 1870s the islands were used by fishermen from Hainan with Itu Aba Island having a semi-permanent settlement of Chinese fishermen.[1]

The bank rises steeply from surrounding depths ranging from 500 to 700 meters. It is 32.05 nautical miles (59.36 km; 36.88 mi) in length, and extends west from the Gaven Reefs to the NW of Dangerous Ground.[2][3] The atoll is up to 11.36 nautical miles (21.04 km; 13.07 mi) wide. The total area is 953 square kilometres (368 sq mi), and the greatest depth of the central lagoon is 80 meters.[4] The central lagoon generally is 10 to 40 meters deep,[5] although many coral heads have much shallower depths. There are several entrances into the lagoon.

The bank contains a number of features along the rim of the reef, including shoals, reefs, islands, and cays, numerous wrecks, some lighthouses, and an ammunition dumping ground in about 2000m of water to the north of Itu Aba.[6] Several coral heads with depths of 6-12m lie in the lagoon, and depths "3.7m less than charted can be expected. ... Mariners should navigate with extreme caution in this vicinity."[2]

Features in the area include:[2]

  • Namyit Island (10°11'N 114°22'E) on the S side of the bank is about 12 miles S of Itu Aba. It is less than a metre high and covered with small trees and brush.
  • Gaven Reefs (10°12'N 114°13'E) consists of two reefs which cover at high tide and lie 7 miles W and 8.5 miles WNW of Namyit Island.
  • Itu Aba Island (10°23'N 114°22'E), lies on the NW edge of the bank
  • Zhongzhou Reef (Ban Than Reef / Centre Cay) lies on the north edge between Itu Aba and Sand Cay, 3 miles E of Itu Aba
  • Sand Cay lies on the north edge, 4.5 miles E of Zhongzhou
  • Petley Reef, which dries 0.9m, is about 1 mile in extent and lies on the N side of the bank.
  • Eldad Reef, 7 miles ESE of Petley Reef, is the easternmost drying reef of the group. The reef is 4.5 miles long with the middle section having a depth of about 1.2m, located at the NE end of the reef.

It is neighboured by the Loaita Bank to the North, Discovery Great Reef to the west, and the Union Banks to the south.

References
  1. Tizard Bank - Footnote, The China Sea Directory, Hydrographic Office - Admiralty, published by J D Potter, London 1879, page 66.
  2. Sailing Directions (Enroute), Pub. 161: South China Sea and the Gulf of Thailand (PDF). Sailing Directions. United States National Geospatial-Intelligence Agency. 2017. p. 13.
  3. NGA Chart 93044 shows the area NW of Dangerous Ground.
    Note that this chart incorrectly labels the bank as the Southhampton Reefs - the Southampton Reefs are further east (10°11'N 115°17'E) - and also mis-spells Petley Reef as Peltey Reef.
  4. Atoll Area, Depth and Rainfall, rock.geosociety.org
  5. Wolfgang Schippke: The Tizard Bank, a large reef in the Spratly Group
  6. The ammunition dumping ground is about 6.7 nautical miles (12.4 km; 7.7 mi) to the north in water 1900m deep.
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