The absolute minimum depth at Tranmere Oil Terminal is 40ft/12.2m so depending on moon/tide and reference to charts + tide tables there could be quite easily more than 45 ft at time of berthing. The tidal range is 30 ft /9.14 m. Calculations would have been done to compensate for discharging and ebb.
Does the port display the daily chart datum, ordinance datum locally? Example here showing today only 4m
change of water level, whereas on 30th 7m movement. https://www.ntslf.org/tides/tidepred?port=Liverpool
Then you have to factor in air pressure/ wind directions etc. but not so influential as the moon.