![]() We have spent a few hours fishing the outside of an atoll while we wait for the conditions of a pass to become favorable. Whether we are leaving or entering a pass, we do not want to be surprised by incoming ocean waves. Extra caution is necessary when swells are rolling directly into a pass. Passes funnel water into a narrowing and shallowing area, so in addition to tides, we pay close attention to ocean swell direction. If possible, the best time to enter or exit an atoll is at slack tide when the tide is in transition and doesn’t create a noticeable current in either direction. Remember, atoll passes can have a lot of current, the highest current we have encountered so far is about 5 knots, though I have read of currents up to 8 knots. Your own eyes and a decent set of binoculars will definitely help you determine a good time to enter or exit an atoll. In our opinion, the best way to determine the state of a pass is to check the nearest tide chart and wave report, then approach the pass and observe the state of the sea at the entrance and inside the pass. One such tool is called “The Guestimator” – the name doesn’t inspire great confidence! We have read many accounts of the inaccuracy of all of the tide estimation tools. There are tide charts and applications for predicting when tide will be ebbing or flowing in specific places. This is an example of an outgoing current or ebbing tide meeting open ocean on the outside of a pass – pretty calm in this example. If the current is incoming, often the inside portion of the pass has the short, steep waves where the incoming tide is meeting the waters of the atoll. When the tide is strong and collides with incoming ocean swell, one can encounter short, sharp waves as well as eddies that bounce a boat one way or another. When the tide in the pass is outgoing, or exiting a pass, there are usually choppy, abrupt areas of water near the outward end of the pass. That means that four times a day, at each tide change of two feet, our imaginary atoll moves the same volume of water as 887 olympic sized pools through a pass(es). Instead consider that an olympic sized pool holds 660,000 gallons of water. A two foot tide change would displace 585,366,279 gallons of water but it is hard to relate to that number. ![]() Let’s imagine a perfectly round atoll that has a diameter of 10 miles. To add a bit of perspective about tides within a pass, consider that the lagoon of an atoll can be miles in length and width. Diurnal tides empty or fill an atoll every six hours. Once a navigable pass is found, the state of tide within the pass must be considered before attempting to enter. The pass into Makemo Atoll during calm waters.
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