The Ports and Passes guide is an annual guide that contains data that changes from year to year. The Ports and Passes guide is usually available in early December and can be purchased from one of our many retailers or on our Canadian and US websites.
A current is the horizontal motion of water. A tide is the vertical motion of the sea surface. The gravity of the sun and moon causes the sea surface to rise and fall, which in turn makes massive amounts of water to flow from the open ocean into (and out of) our inshore waters. This is what drives most currents in the waterways of the Pacific Northwest.
The reason you are having trouble is that you are comparing the currents for Sergius Narrows in Ports and Passes with the tides for Sergius Narrows in the NOAA tables. At locations where tidal currents are strong, the turn of the current almost never occurs at the same time as high or low tide.