Guest Writer: John N. Jamieson

Learn to sail like a pro with these sailing safety tips. Each year, you can read another story about a sailboat that tried to sail under a bridge and got into trouble. Or, you might read a story about a sailor electrocuted when he or she attempted to pass under a low hanging overhead power line. Follow these five easy sailing tips to avoid marine accidents like these and keep your sailing safe, fun, and worry-free.

Do You Know Your "Corrected" Mast Height?

Know the height of your sailboat mast for safety. Your sailboat mast height tells you how much clearance --called "vertical clearance"--you need to pass beneath bridges or power cables. Locate your boat sail plan (drawing) or call the manufacturer. As an alternative, you might log on to a trusted Internet forum with experts on your specific sailboat. Ask about the mast height.

Remember to add several feet to account for radio antennas or wind instruments at the top of your mast. If unsure of the height of attachments at the top of your mast, add 10% (rounded up to the next foot) to the mast height.

Look over this example:

You look at your boat's sail plan and note a mast height of 42 feet. You have a VHF radio whip antenna at the top, but are unsure of the height of this antenna. How much clearance do you need for safe passage?

42 feet x 10% = 4.2 feet. Round this up to the next whole foot. 5 feet + 42 feet = 47 feet corrected mast height. Write this down in your boat log for reference.

How are HEIGHTS shown on Your Chart?

Find the printed chart note on any nautical chart that says "HEIGHTS" in all capital letters. Read the note below that title. On US charts, heights are shown at mean high water (MHW), or the average of high waters over a period of years. On British Admiralty charts, heights are given at mean high water springs (MHWS), or the average of spring high tides over a period of years.

Know the Four Nautical Bridge Symbols

Fixed bridges

Fixed bridges span a waterway from one side to the other. On you chart, these bridge symbols form unbroken lines across the water. Find the vertical clearance of the bridge marked near the charted symbol.

Bascule bridges

Imagine those old movies of the drawbridges on castles, where one side of the bridge lifts up. Bascules are the modern name for "drawbridge", and always lift up on one or both sides on a hinge. On your navigation chart, bascules show an open section in the middle of the waterway. Most bascule bridges are too low for sailboats to pass beneath, so you must call the bridge tender on your marine radio and request that they open the bridge.

Swing Bridges

These bridges rotate in a horizontal motion on a central pivot. Swing bridge symbols show an opening in the center, with a small, slender, oval shape in the center of the opening. This slender oval shape will be drawn perpendicular to the span. Most swing bridges are too low for sailboats to pass beneath, so you must call the bridge tender on your marine radio and request an opening.

Lift Bridges

These rare elevator-like bridges rise in a vertical motion between two giant legs. The symbol shows an unbroken span, but near the center, you will see two small arcs next to one another. Each arc faces the nearer river bank. Lift bridges have limited clearance when in the down position. Call the bridge tender on your radio and request an opening.

Double Check Clearance Before You Pass Through

Look for a tide gauge, shown on a board or in some cases, a digital display near the entrance on each side of the bridge. This shows the actual amount of clearance at that moment. Make sure that you have plenty of clearance before you attempt to sail through. If necessary, wait for a lower stage of the tide to pass though in safety.

How to Identify Deadly Overhead Power Cables

Few symbols hide like the overhead power cable. These high voltage wires span narrow waterways from one bank to the other. Look for dashed magenta colored (purple) lines on your chart. You will sometimes see a circle on each side of the waterway, that represents the power cable towers.

Use a bright colored highlighter and mark power cable symbols on your chart. That way, they are easier to locate at-a-glance. Look on one side of the waterway for the vertical clearance of the cable. Make sure that you have lots of spare vertical clearance before you attempt to sail under any cable. If necessary, find an alternate route or anchor and wait for a lower tide before you attempt passage.

Use these easy sailing tips to learn to sail with confidence in areas where bridges or power cables exist. Keep your sailing safe and worry-free--wherever in the world you choose to sail!


Article by: John N. Jamieson

Captain John with 25+ year of experience shows you the no-nonsense sailing skills you need beyond sailing school! Sign up for his FREE highly popular "Captain John's Sailing Tips" Newsletter. Find out how you can get instant access to over 550 sailing articles, sailing videos, newsletters and more at SkipperTips

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