Sailing Navigation Secrets - How to Pass Through a 'Flashing Gate'

by John Jamieson on 20 Oct 2012 Imagine that you need to enter an unfamiliar channel just after sunset. You have an injured crew aboard and must get him or her to a medical facility as soon as possible. You proceed with caution from buoy to buoy. Up ahead you see a row of blinking yellow lights strung across the channel from bank to bank. There are no other alternative channels, and deadly shoals surround you on both sides. You need to pass through the obstruction ahead. Now what, skipper?

Sail long enough and you will encounter channel maintenance operations. This includes cable or pipeline laying, dredging operations, or bridge construction or repair. Here, we will discuss the first of these--cable or pipeline construction across the channel from one side to another. Be aware that underwater pipelines while in the construction phase can cause costly damage. Vessels have had rudders ripped off, keels damages, props and shafts mangled, and crew injured from impact.

In non-emergency situations, the wisest move may be to anchor and wait until daylight to pass through if inshore. Or, if offshore approaching landfall and you see a string of flashing lights ahead, heave-to until daybreak.

But, you will still want to know how to navigate through a pipeline area in safety. You may find that you need to access the other side of the pipeline to:

* Bring an injured or sick crew ashore.
* Gain access to safe moorings or anchorages further inshore.
* Take shelter inshore from oncoming heavy weather.

How to Find the Pipeline 'Gate' Opening

Look to the Navigation Rules to identify the way pipeline lights and pipeline openings are marked. Annex V--also known as the 'Pilot Rules'--applies to all vessels that operate on US Inland or Canadian Waters of the Great Lakes. Dredge pipelines must be marked like this:

Lights Along the Length of the Pipeline

Lights along the length of the pipeline must be yellow and staggered at equal intervals. Each yellow light will flash 50 to 70 times per minute. Each light must be visible for two miles on a clear, dark light.

Lights that Mark the Opening in a Pipeline

Find the narrow gap in the pipeline that marks an open slot for vessels to pass through in safety. Look for two red, non-blinking lights in a vertical line at each end of the pipeline. These will be visible all around the horizon for two miles on a clear, dark night. The lower red light on each side will be at the same height as the yellow blinking lights. The higher red light will be a minimum of one meter (3.3 feet) above the lower red light on each side.

With this knowledge, you can pass through the pipeline in safety, access the other side of the channel, and keep boat and crew damage- and injury-free---wherever in the world you choose to cruise!

..........................

John Jamieson (Captain John) with 25+ years of experience shows you the no-nonsense cruising skills you need for safer sailing worldwide. Visit his website at www.skippertips.com for a free issue of the highly popular 'Captain John's Sailing Tips' newsletter.
Discover how you can gain instant access to hundreds of sailing articles, videos, e-Books and more!