Broadcast Notices to Mariners

Electrical and electronic topics for small boats
jimh
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Broadcast Notices to Mariners

Postby jimh » Mon Apr 04, 2016 11:44 am

In the United States of America and in Canada, the maritime agencies (USCG and CCG) make radio broadcasts of important navigational messages in periodic Broadcast Notices to Mariners or Notices to Shipping. It is a prudent practice for all mariners to be alert for these radio broadcasts, which are usually sent via VHF Marine Band radio. I briefly review two instances of navigational alerts with which I have some association.

On the morning of Tuesday, August 2, 2011 we were enjoying breakfast aboard our modest boat while still at the dock at St. Amant's Marina in Britt, Ontario, a harbor on the eastern shore of Georgian Bay. As is my usual practice, I was listening to the continuous marine broadcast from the Canadian Coast Guard. These broadcasts typically include a number of Notice to Shipping announcements that are applicable in the region. The Notice to Shipping announcements are continually repeated, and can be heard at about ten minute intervals. On that morning, I heard NOTICE TO SHIPPING C-1673 for Chart 2204. It reported that Buoy D42 was presently located 30-meters West of station. Our plans were to transit that area later in the day, and I made a note of the off-station buoy, which was about ten miles away in a narrow passages known as Rogers Gut. When we reached that area we noted D42's position and did not follow the course that it would have us take, but instead relied on our electronic chart plotter to guide us along the preferred route, indicated on our charts with a magenta line. We passed through Rogers Gut without incident.

On the evening of January 26, 2012, the roll-on/roll-off vessel DELTA MARINER was navigating downbound on the Tennessee River. Ahead of them was the Eggner's Ferry Highway Bridge. I have navigated this portion of the Tennessee River myself and have transited under the Eggner's Ferry Highway Bridge, so I am acquainted with this area. On the night of January 26, however, the bridge's obstruction lighting (that is required to be exhibited to boaters passing under it) was not working properly. The USCG was aware of the outage in the bridge lighting and the hazard it represented to mariners, and they were broadcasting a notice to mariners about it. On January 26, an alert of the broadcast was made twice, once at 0400 and again at 1613, on Channel 16. On the bridge of the DELTA MARINER at 1613 the loudspeaker of their VHF radio monitoring Channel 16 provided the bridge crew an alert of this Notice to Mariners, and instructed them to turn to Channel 22A for details. None of the bridge crew took notice and the radio was not switched to the other channel to hear the alert. The crew continued downbound toward the bridge without awareness that its navigation lighting was not working properly

The DELTA MARINER is a specially-designed vessel build to have an air draft that would permit passage under the Eggner's Ferry Bridge with a clearance of about three to four feet at typical water levels, but only under the highest span of the bridge, which consists of five separate spans. On navigation charts for these waters the "sailing line" or preferred course line is marked with a magenta line and shows passage under the bridge using Span B, the span with the highest clearance. This span is normally identified by three white lights in a vertical line at the center of the span above a green light.

Due to the outage in the bridge lighting, none of the lights on Span B were illuminated. Only three lights were visible: two red lights marking the concrete piers of Span E, and a green light marking the center of Span E. The rest of the bridge, its piers, and its spans were not illuminated. Span E is about 800-feet away from the "sailing line" course shown on the charts.

A few minutes before the DELTA MARINER reached the bridge, the master of another large commercial vessel navigating in the area contacted them by VHF radio to inform them that "the lights were out" on the bridge and questioned their vertical clearance at the bridge. The DELTA MARINER acknowledged that radio call. They continued on toward the bridge relying on navigating the vessel by visual observation of the bridge's lighting and ignoring their electronic chart plotters, taking a course heading for the only-visible green light, the one marking Span E's center, a span whose vertical clearance was insufficient to permit passage of the ship, and maintained their speed of 11.5-MPH.

Moments later at 2001-hours the superstructure of the DELTA MARINER struck the bridge span, tearing it away from the bridge piers. The ship carried on about 275-feet further, coming to a stop with about 660,000-lbs of bridge steel resting on its foredeck. There were no injuries and the ship's cargo, DELTA IV rocket components, was not damaged. Fortunately, highway traffic on the bridge was light, and no vehicles drove off the bridge's missing span into the water. Repairs to the ship cost about $2.6-million, and the ship was out of service for about one month. Repairs to the bridge cost about $7.2-million and the bridge reopened for traffic on May 25, 2012, about four months after the incident.

As these two incidents illustrate, it often pays to listen for broadcast notice to mariners. For more details on these two incidents see:

Georgian Bay 2011
A Perfect Cruise Around Georgian Bay

http://continuouswave.com/sail-logs/gb2011/

Allision of the Cargo Vessel M/V Delta Mariner with
Eggner’s Ferry Bridge, Tennessee River
Near Aurora, Kentucky
January 26, 2012

http://www.ntsb.gov/investigations/Acci ... AR1302.pdf

The NTSB report (linked above) make for very interesting reading, and I recommend it as a good example of how no single method of navigation should be solely relied on.