Safe boaters can control many things on their vessel – wake, fuel consumption, generator use, heading and speed, life jackets on all passengers, etc. But one thing even the most responsible boater can’t control is the daily rise and fall of the sea caused by the gravitational pull of the sun and the moon: a remarkable process known as the tides.
Avoiding this powerful cycle is not an option. The key is learning to monitor the tides and adapt your activity accordingly.
Tidal ranges can vary from as little as a foot between high and low tides to more than 40 feet in exceptional cases. Tides also cause strong currents. Here are some of the common hazards:
• Tides affect anchoring. Too much at high tide in a crowded anchorage and your boat can drift into other boats at anchor. Too little anchor line at low tide and your boat can come adrift as the tide rises. Worse, if the anchor holds, it can hold the bow down and allow water to enter, possibly sinking the boat.
• Tides can affect docking to a fixed pier. At high tide, lines tied too short can leave your boat suspended in midair when the tide goes out. At low tide, lines tied too short can swamp the boat as the tide comes in. This situation has caused many a deck fitting, cleats, rings, etc. to be ripped out as the tide changes.
• Tidal currents can be strong enough that some vessels are not able to make headway against the current, thus delaying launch and recovery.
• At low tide vessels can run aground in areas where navigation is otherwise safe. This is an important concern if you keep your boat in a cove or marina that you can only get into or out of at high tide.
Tide tables are available through commercial vendors in various formats, including printed versions. Regional charts can be found online through the website of the NOAA National Ocean Service at http://tidesonline.nos.noaa.gov/. You can also take advantage of new tide tracking technology being incorporated into boat GPS units and nautical watches.
If you confine your boating to your local area, the tide information in the area newspaper, on a local calendar, or broadcast on local radio may be all you need. If you are going cruising for several weeks over a wide area, however, you will need tide tables for your entire cruising area.
The U.S. Coast Guard reminds all boaters to “Boat Responsibly!” For more information and tips on boating safety, visit www.uscgboating.org
Here's a clue from the U.S. Coast Guard:
Check the Tides