TidesandCurrents
MACKAY
TIDES AND CURRENTS
According to information provided by the Mackay Port Authority, the highest astronomical tide at Mackay is 21 ft (6.41 m). The normal range of astronomical tide levels is from 6.4 ft to 13.3 ft (1.94 m to 4.06 m) for neap tides, and 2.4 ft to 17.3 ft (0.72m to 5.28 m) for spring tides (Mackay Port Authority, undated). Mackay tide data listed on DMA Chart 74229 differs only slightly from the preceding figures, and lists mean sea level as being 9.8 ft (3.0 m). The datum level for the tide levels is 0.33 ft (0.1 m) below Indian Spring Low Water (ISLW) as defined in the 1958 edition of the American Practical Navigator.
DMA (1990), states that tidal currents set south on the flood tide and north on the ebb at a maximum velocity of 2.5 kt. The strongest current flow is attained during periods of maximum tide change. The tidal currents are strong enough to prompt the recommendation by a U.S. Navy vessel that visited the port in 1988 that Mackay Harbor should be entered only at slack water.
Source: http://www.nrlmry.navy.mil/port_studies/thh-nc/australi/mackay/text/sect6.htm
