=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 11-Jun-1991
Alert Bay           822/021 RLR(1968) is 14.4m below BM 5,1965
=========================== FOLLOWING PSMSL DOCUMENTATION ADDED 19-Aug-2010
To clarify the RLR diagram BM 1 1947 was in use 1947-1957, BM 2 1947 was in use 1957-1965. BM 5 1965 came into use 1965 onwards. RLR facto is 4.075m. BM 5 1965 is 14.4m below TGBM BM 5 1965.