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Making Waves: Episode 37 (October 16, 2009)

Today, many busy ports around the nation are marking World Maritime Day with ship tours, ceremonies, and other special events. The day is about highlighting topics that most of us don’t think about very often: ships, ship safety, navigation, and other maritime activities.

In this spirit, we’re privileged to have the director of NOAA’s Coast Survey join us. We’re going to cover a lot of water in this episode … Want to know what nautical charts have to do with Thomas Jefferson, mine sweepers, and the stuff you buy in a big box store? Just how big are some of the ships plying our waterways these days? What effect might rising sea levels have on the future of shipping? Stick around to find out.

It’s October 16th, 2009, it’s World Maritime Day, and this is Making Waves from NOAA’s National Ocean Service.

World Maritime Day

Today we’re joined by Captain Steve Barnum. Captain Barnum has been a NOAA Corps officer for nearly three decades, he’s captained five different NOAA ships during his career, and for the past three and a half years he’s served as the director of NOAA’s Coast Survey and as the U.S. National Hydrographer. 

What exactly does he do in his current job? Well, we’ll let Captain Barnum explain in his own words:

[Captain Barnum] “I’m the belly button, if you will, for nautical charting for the United States. So I’m responsible to produce nautical charts for safe shipping for all of our waters to include the territories and the Exclusive Economic Zones. So about 3.4 square million nautical miles.”

Nautical charts are like maps, but there’s a difference. While maps show you where you can go, nautical charts show you where you can go and where you can’t go. Nautical charts show what the coastlines look like, water depths, what the sea bottom looks like, dangers to navigation, and locations of navigation aids to help a mariner get from point A to point B safely. In other words, charts help keep ships from turning into shipwrecks.
While that’s pretty straight forward, how these charts are produced is a more complicated story – and it may surprise you. The main thing to know is that the U.S. has an incredible amount of shoreline and underwater territory to chart. Over the years, the tools we’ve used have ranged from the simple –- from taking soundings, or depth readings, by dropping hunks of lead tied to a rope -- to mapping the depths with state-of-the-art sonar and satellites. . It’s not an easy job … mariners have been at it for over two centuries now, and it’s still a work in progress.

[Captain Barnum]  “There are literally about 95,000 linear nautical miles of shoreline and as I said earlier about 3.4 square million nautical miles of underwater territory. About half of that still has lead line soundings – and those are soundings that are taken with a, if you think in terms of lead with a rope on the end of it. And some of that data may extend back into the 1800s or to the days of, in the case of the Alaskan charts, shoreline that was derived from the Russian charts when we purchased it. So it’s taken us 200 years to map our coasts, and there are still many parts that are uncharted, and many parts we don’t know much about, and the information is old, but it’s the best information we have. Take this in context. It sounds pretty dire for the United States, but if you look at it in a world view, only five percent of the oceans have been mapped to modern standards, and many of those areas have never been charted – particularly areas of the Arctic and some other regions of the world are blank, meaning there’s no soundings.”  

Now it’s important to note here that critical shipping lanes, ports, and harbors are charted in fine detail using modern tools like multibeam and sidescan sonar. This level of detail is critical for safe navigation in our busiest waterways, of course, but there’s another side to it that not many people think about.

[Captain Barnum]  “National security is actually one of the prime needs for having accurate nautical charts. Military vessels have to be able to come and go freely from our ports and without accurate nautical charts, their movement would be impeded – it would subject them to unnecessary risk.”
High-detail sonar readings of the bottom of the sea floor can also play a big role during Homeland Security threats.

[Captain Barnum]  “One of the uses of the multibeam sonar and sidescan sonar is that we can get a good accurate picture of the bottom. It’s very useful to the Navy if somebody says they put something in the water, because if we have an accurate baseline of an image of all the objects on the bottom, then again, if someone puts something in the water or says they put something in the water, the mine hunters will come in and they can much more efficiently sweep a harbor to open it back up for business. And our economy operates on a just-in-time basis, meaning that in some cases, some ports only have two or three days of fuel or supplies, so it’s very important to be able to open up a port quickly in the event of a disaster or somebody saying they may have put some improvised explosive device in the water.”

So now we’ve talked about two big uses for nautical charts: safety and national security. But Captain Barnum just touched on another important aspect of why charts are critical, and that’s the economy. Well, safety, security, and commerce have been the driving forces behind the development of charts for over 200 years. And this is something else that may surprise you: this branch of NOAA traces its roots back to the early 19th century. It’s the oldest scientific agency in America.

[Captain Barnum]  “The Coast Survey, or Survey of the Coast as it was called in 1807, was established by President Thomas Jefferson and the reason he established it was because more ships were being lost at sea to shipwrecks and poor charts than to ships at war, and so he saw the value of shipping to the prosperity of the United States for trade.”

That – the value of shipping to our nation’s economy – is more critical now than it’s ever been. If you add up all the ships and barges carrying goods around the nation, you begin to see how colossal our Marine Transportation System is. By weight, our marine highways carry more than three-quarters of all U.S. goods and supplies. This cargo contributes more than $750 billion dollars to the nation’s economy and creates jobs for more than 13 million people. Captain Barnum puts it like this:

[Captain Barnum]  “Nautical charts are one piece in the larger marine transportation system, and the marine transportation system is a system that I think the general public is unaware of. Not that they may not be appreciative of it, but it’s been termed the ‘hidden highway’ or the ‘hidden transportation system.’ It’s phenomenal. Ninety-five percent of our goods by weight arrive by ship. Well over half our domestic oil consumption comes by ship. The grain that we export to countries around the world goes by ship. So our economy depends on it.”

And those ships are getting bigger and bigger. They stick up out of the water higher than ever before, and their draft – the part of the ship below the water – can extend down as far as a five-story building. This adds another layer of complexity to managing the maritime highway in the 21st century.

[Captain Barnum]  “The vessels today are bigger than ever. Some of these vessels are in excess of a thousand feet in length, in some cases over a hundred feet in width. Some ships are so large they never see land. There’s a port of the coast of Louisiana called the Louisiana Offshore Oil Platform where these ultra deep draft tankers come to discharge their product. Out of site of land, and that’s because the drafts are so deep. In many of our ports, they’re challenged by these larger ships because the infrastructure has not kept up with the pace of change with the size of these ships. And the larger ship – it’s an economy of scale issue – the larger the ship the more efficient it is to carry the product with a certain number of crew. So these larger ships as they try to navigate in the waters in our various ports in our nation are challenged in many ways. Not only from the draft in the channels, the waterways leading into the port, but also the infrastructure of the bridges that span many of these waterways. Who would have thought that the Verrazano Narrows Bridge in the approaches to New York, for those who have seen that, would have been an impediment to some of the ships today.”

The Verrazano Bridge, by the way, is the largest suspension bridge in the world.  The roadway of the bridge is 226 feet above the water.  So we know that the marine highway is huge, and that ships are getting bigger. Well, traffic on our waterways is also on the rise. By some estimates, this system is expected to double or even triple in size by 2020. Captain Barnum said that one of the main driving forces is that it’s just so much more economical to ship our goods around by ship.

[Captain Barnum]  “Up until our recent financial setback, shipping was growing at about seven percent a year. Which is pretty phenomenal growth. And there’s increased pressure on our waterways and so a lot of folks are also looking at smart transportation of how to get trucks off the roads, using these underutilized waterways. So you’d have these major ports with feeder ports – going from these larger ports to these smaller ports – again to get vehicle, truck traffic off the road. And also to be a much more efficient movement of goods and services. A barge with a tug can carry much, much more product or goods than an equivalent amount of trucks, much more efficiently.”

How much more efficiently? Picture this:

[Captain Barnum]  “Ships that used to carry two to three thousand – they’re called terra-equivalent units – think of them as containers or a box, a tractor trailer box. Some of the latest ships carry 15,000 TEU, so think of that as 15,000 tractor trailer boxes on a ship, and think about what that means, the capacity when you look at the number of trucks today on the interstate, and think ’15,000.’ This is just one ship.”

This may be the future: bigger ships, and more of them, carrying more of our goods and products around the nation’s waterways, often sliding into ports with only inches to spare from the tops of bridges or the bottoms of channels. The tricky part of this business for Coast Survey is that our waterways are ever-changing. The hazards on the bottom of the sea floor don’t stay in one place, so work continues non-stop to keep nautical charts up to date. In the future, this task could get even more challenging. Before we let Captain Barnum go, we threw out one last question. How might climate change affect the maritime transportation system?

[Captain Barnum]  “I’m not sure that we know exactly what the impacts will be. We know what the impacts could be with sea level rise. Of course, that’s going to give all the ships more draft. I talked about existing infrastructure – that’s going to make less distance between the bottoms of the bridges and the surface of the water, so they’ll have a tougher time fitting under these bridges. Certainly there are issues with the waterfronts and there’s transportation infrastructure of the rail and the highway connections. It’s not just the ships coming to the ports. They have to be able to offload their goods and product and get it onto the rail and other transportation systems, and to get it to Middle America, so much of that infrastructure is at risk with sea level rise, and it’s something that will have to be addressed as we look to the future.”

That’s all for the World Maritime Day special episode. We hope you learned something new about the maritime activities going on each day around the country.

A special thanks to Captain Steve Barnum, director of NOAA’s Office of Coast Survey and U.S. National Hydrographer, for taking the time to speak with us today. And we wish him fair winds and following seas – Captain Barnum is retiring at the end of the month after 29 years of service in the NOAA Corps.

Well, you don’t need a nautical chart to find our Web site. Sail over to if you have any questions about this week’s podcast, about the National Ocean Service, or about our ocean. And if you want, you can also send us an email at

Now let’s bring in the ocean....

This is Making Waves from NOAA’s National Ocean Service.