Avoid Sailing Near These “Ship-Killing” Nautical Chart Dangers

Here’s another helpful sailing tip from our friend Capt. John at skippertips.com

Could you glance at any nautical chart or GPS plotter and pick out the wreck symbols at a glance? Sail too close to these hazards and your hull could become impaled, your keel cracked, or your propeller and shaft mangled. Learn to recognize the three most common “ship killers” at a glance for safer sailing on the waters of the world.

If you are anything like me, the symbols and abbreviations on a navigational chart are like a treasure chest of information. Unlock their meaning and you have a virtual “3-D” of useful info to keep your boat and crew safe and sound.

Here are three wreck symbols to get you started on the road to navigation safety wherever you sail. These three are the most common wreck symbols you will find on nautical charts. Use the descriptions below along with the illustration to learn more about these deadly hazards:

1 – Wreck Not Dangerous to Surface Navigation–but Still a Danger!

Symbol 1 shows a wreck that has been determined not to be dangerous to surface navigation at all stages of the tide (high water and low water). Note that this wreck symbol has not been surrounded by dots.

You can plot a course over this charted wreck symbol and be confident that your keel, rudder, or propeller shaft will not be damaged. So why do cartographers (chart-makers) bother to put these onto your chart?

For the sailor, you would not want to anchor anywhere near a non-dangerous wreck symbol. If your anchor dragged just the slightest distance, it could become fouled (snagged or caught) on the wreckage or pieces of the wreckage. Wrecks tend to shift position, so it’s best to stay well clear.

On the commercial side, fishing vessels that use bottom nets want to know where these wrecks are to avoid the possibility of snagging their nets as they trawl along the bottom. That could end up costing them thousands in repair or replacement costs.

2 – Dangerous (Sunken) Wreck Hazardous to Surface Navigation

Symbol 2 shows a wreck that has been determined to be dangerous to surface navigation at all stages of the tide (high water and low water). You can tell this because the fishbone symbol has been surrounded by dots. Charted symbols surrounded by dots ramp up the level of danger to your boat. Plot your course to keep clear of these underwater “boat back-bone breakers”!

3 – Wreck Showing Any Portion of Hull or Superstructure

Symbol 3 looks like part of a ship or boat that sticks out of the water at all stages of the tide (high water and low water). The half-hull wreck symbol tells you that at all stages of the tide, some portion of the hull or superstructure will be visible.

But beware…

At higher high tides, there may be just the slightest bit of wreckage above water. And it could be obscured by waves or low visibility conditions (or darkness). These dangerous wrecks have their positions indicated by the small white open circle (note the circle at the base of the charted symbol). Avoid these monster hazards like the plague to prevent serious damage or injury.


Use Chart No. 1 “Nautical Chart Symbols, Abbreviations and Terms”, to learn more about the chart symbols and abbreviations used on nautical charts throughout the world. Download a copy of this vital companion to the sailing navigator here =>http://www.nauticalcharts.noaa.gov/mcd/chartno1.htm


Learn these vital wreck danger symbols to sail clear of underwater hazards to sailing navigation. Discover dozens of other symbols that show wrecks, rocks, and obstructions in Chart No. 1. Use this knowledge to help keep your sailing crew and small sailboat safe and sound–wherever in the world you choose to sail or cruise!

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