If you are planning a route, you will need a source of information about currents on your route as well as tides, because there can be many places where you cannot figure out current direction and strength based simply on local tide times. Slack Tide - The period in the tide cycle when there is little or no current. Slack water occurs approximately halfway between maximum ebb and maximum flood and can last for 15 to 45 minutes. Notice this is not the same as halfway between high tide and low tide - refer to the Bay Area tide chart below for a rough representation of the relationships between ebb, flood, slack, high and low water tides and their approx. 6 hr. intervals.
“There is a tide in the affairs of men, which, taken at the flood, leads on to fortune; Omitted, all the voyage of their life, is bound in shallows and in miseries. On such a full sea are we now afloat; and we must take the current when it serves, or lose our ventures.” - Shakespeare “Julius Caesar”