lished between 1912 and 1935. The updates
highlighted changes in lights and buoys,
variations in typography, and new hazards to
navigation. The red-line markings remained
much the same over these 23 years.
Now, let’s move forward to 1935,
and America’s struggle to get out of the
Great Depression. Among the many government programs to stimulate the economy and get people working, the Public
Works Administration more than tripled the
USC&GS budget. These additional funds
greatly increased the agency’s ability to do
its job, and one project it undertook was to
modernize nautical charts. The agency doubled the number of workers available to conduct field surveys of the waterways. Noting
the increasing demands of commercial traffic,
they also changed the controlling depths
to fit the draft requirements of this traffic.
The surveys specified depths of no less than
seven feet on the Atlantic waterway and
no less than six feet out to Corpus Christi.
The substantial investment in this project
greatly improved the charts and the entire
waterway system, which now stretched from
New York to Texas. The new charts included
updated magenta-line detail. In the years
since, authorized depths have been modified
and additional surveys have been conducted,
but for the most part, the magenta line has
not changed since 1936.
Where DoeS Tha T Leave US?
Surprisingly, the magenta line has not been
“owned” by any federal agency for quite some
time. It seems to have gotten lost among the
other realities that define the national maritime landscape. Today the Atlantic and Gulf
ICW systems are managed by the U.S. Army
Corps of Engineers. NOAA Office of Coast
Survey doesn’t even survey the ICW, except
when requested by the Corps of Engineers in
special interagency instances, as in the case
of post-Sandy storm damage assessment.
But that isn’t to say the magenta line has
been untouched. For some period of time,
inaccurate portions of the magenta line were
simply deleted. It was felt that nothing was
KEEPING OUR CHARTS ACCURATE
THE MAGENTA LINE isn’t the only line on our charts that requires updating. With 500,000 square nautical miles of navigable waters in our country, and 95,000 miles of shoreline, NOAA’s Office of Coast Survey has an enormous job. These days, underwater
mapping has become more complicated than ever, with rising water levels, shifting sediments,
shoaling, and the increasing number of extreme storm events. All these changes significantly
impact the underwater landscape, making NOAA’s job more crucial than ever.
NOAA has four primary survey vessels — two on the East Coast, two on the West. Together
with contract vessels, they survey approximately 3,000 square nautical miles of U.S. waters
each year. In 2013, that number will be greater given the additional survey needs in the
Northeast due to the altered shoreline from Superstorm Sandy. Data is collected and processed aboard the ship, around the clock, then sent to one of two processing facilities, in
Norfolk, Virginia, and Seattle, Washington. In areas with rugged shorelines where survey vessels can’t operate safely, aircraft determine near-shore water depths through bathymetric
At the processing centers, staff sort through the millions of soundings to determine those
most significant to cartographers. For example, if an area is 30 feet deep and then becomes 29
feet, 8 inches, does that need to be recorded on the chart? While a four-inch difference may
not be that important to recreational boats, inches determine how much can be loaded onto a
ship in a shipping channel and can have an enormous economic impact.
Data is then sent to the Marine Chart Division of NOAA in Silver Spring, Maryland, and
transferred to paper, raster, and electronic nautical charts. In bygone days, data was hand-etched in reverse onto copper plates! Now it happens digitally. For paper charts, data is sent
to the Federal Aviation Administration, which prints them. There are also print-on-demand
charts, new booklet charts, and electronic navigation charts that are free for download or may
be purchased through a provider ( www.nauticalcharts.noaa.gov/staff/chartspubs.html). In all, it
takes about a year from the ship survey to inclusion in NOAA’s database of electronic charts.
For urgent changes, such as a hazard to navigation, NOAA survey vessels submit “Danger to
Navigation Reports” as soon as practicable after discovery and ahead of the complete survey
package for incorporation into “Notice to Mariners.” Every paper chart has an edition number
and date (month and year of printing) in the lower left-hand corner. To see if NOAA has updated your chart, go to Dates of Latest Editions at www.nauticalcharts.noaa.gov/mcd/dole.htm
— Susan Shingledecker, BoatU.S. Foundation For Boating Safety &
Clean Water; Member, NOAA Hydrographic Services Panel
eaST coaST aLer TS: Boa TU.S. crUiSing exper TS ToM anD MeL neaLe
have The La TeST UpDa TeS on naviga Tion, Wea Ther, anD any Thing
eLSe Tha T Migh T pop Up. WWW.Boa TUS.coM/crUiSing/ToMneaLe
curious where the noaa ships are
currently surveying or what it’s like
to be an noaa hydrographic officer?
See this article online to find out,
worse than providing incorrect information,
so it was better to remove these areas rather
than keep them on a chart to mislead mari-
ners. One might argue this made sense, but it
was a short-term fix that ignored the grander
vision of improving the overall system. In
March, Commander Shepard Smith became
the new chief of Coast Survey’s Marine
Chart Division. With his appointment comes
opportunity. CDR Smith’s office wants to
review the current state of the magenta line,
assign responsibility for it, and develop a
plan to make it an accurate and safe naviga-
tion tool for all mariners. These efforts will
likely involve the U.S. Power Squadrons,
U.S. Coast Guard Auxiliary, perhaps even
BoatU.S. His office expects to invite the boat-
ing community to participate.
The concept of a protected inland waterway along our coast is as valid today as it was
a century ago. A national treasure, wondrously rich in history and natural beauty, the ICW
still offers outstanding utility for commercial
and recreational use, and is a lasting tribute
to our nation’s maritime heritage. As for the
magenta line, good things are on the horizon
for a navigation tool that hasn’t had much
attention in almost 80 years. Stay tuned.
Bill and Laurene Parlatore founded PassageMaker
magazine, and enjoy boating in many forms,
including recent adventures on the French canals.