Boating and Sailing.pdf - Moja ladja

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Part 4: Nature’s Triple Play: Wind, Weather, and Tides
Tides can be expressed in charts as well as in numeric tables. This chart, from the Tampa Tribune,
uses a graph to show highs and lows for a week.
Using the Tide Tables
The tables list tidal locations in geographical order from north to south and east to west;
thus Miami, Florida, comes ahead of Brownsville, Texas. There’s an index to look up the
station nearest your location.
The table for a given spot lists dates; time of the tides in military time, with 0100 standing
for 1 A.M., 1200 standing for noon, and 1800 for 6 P.M.; and the height of the maximum
and minimum tides for the day.
Tide Heights and Navigation
If your boat has a draft of three feet, the lowest part of it, probably the skeg, will touch
bottom in water that’s 2'11'' deep. If the mean low tide at a given spot is 3.0 feet and you
cross on an average low tide, you won’t touch bottom. If you cross on a –0.2 low tide,
things will scrape and bump and possibly bend.
But there’s more. If there are waves rocking your boat up and down, the water on the
shoal will go from deeper to shallower with every cycle of peak to trough. On the bottom
of the trough, you may strike bottom, even though you could cross the bar in calm seas.
You have to use your judgment and perhaps wait for the tide to flow back in before you
cross that particular spot. You refer to the tide tables to see when the water will be rising,
and “guesstimate” about when you can cross by looking at the time of high tide and the
sea conditions.
By the same token, perhaps there’s only a foot of water over a bar at a creek mouth at
mean low tide, and that’s two feet less than you need to get in. But wait until the peak of a
+3.0 tide, and there’s no problem. That is, there’s no problem unless you want to leave