1954 - 1961 Data supplied by the British Hydrographic Dept.
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 11-JUN-91 :
Sembawang           555/051 RLR(1955) is 9.9m below TGBM
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 12-Oct-2010 :
ACD 1954-1985 is 4.892m below TGBM. ACD 1986 onwards is 4.923m below TGBM. RLR (1955) is 9.9m below TGBM.

