Julia West: This Is What Drives Us, April 1, 2015

NOAA Teacher at Sea
Julia West
Aboard NOAA ship Gordon Gunter
March 17 – April 2, 2015

Mission:  Winter Plankton Survey
Geographic area of cruise: Gulf of Mexico
Date: April 1, 2015

Weather Data from the Bridge

Date: 3/31/2015; Time 2000; clouds 25%, cumulus and cirrus; Wind 205° (SSW), 15 knots; waves 1-2 ft; swells 1-2 ft; sea temp 23°C; air temp 23°C

Science and Technology Log

You’re not going to believe what we caught in our neuston net yesterday – a giant squid! We were able to get it on board and it was 23 feet long! Here’s a picture from after we released it:

giand squid

Giant Squid!

April Fools! (sorry, couldn’t resist) The biggest squid we’ve caught are about a half inch long. Image from http://www.factzoo.com/.

Let’s talk about something just as exciting – navigation. I visit the bridge often and find it all very interesting, so I got a 30 minute crash course on navigation. We joked that with 30 minutes of training, yes, we would be crashing!

From the bridge, you can see a long way in any direction. The visible range of a human eye in good conditions is 10 miles. Because the earth is curved, we can’t see that far. There is a cool little formula to figure out how far you can see. You take the square root of your “height of eye” above sea level, and multiply that by 1.17. That gives you the nautical miles that you can see.

So the bridge is 36 feet up. “Really?” I asked Dave. He said, “Here, I’ll show you,” and took out a tape measure.

Dave measuring height

ENS Dave Wang measuring the height of the bridge above sea level.

OK, 36 feet it is, to the rail. Add a couple of feet to get to eye level. 38 feet. Square root of 38 x 1.17, and there we have it: 7.2 nautical miles. That is 8.3 statute miles (the “mile” we are used to using). That’s assuming you are looking at something right at sea level – say, a giant squid at the surface. If something is sticking up from sea level, like a boat, that changes everything. And believe me, there are tables and charts to figure all that out. Last night the bridge watch saw a ship’s light that was 26 miles away! The light on our ship is at 76 feet, so they might have been able to see us as well.

Challenge Yourself

If you can see 7.2 nautical miles in any direction, what is the total area of the field of view? It’s a really amazing number!

Back to navigation

Below are some photos of the navigation charts. They can be zoomed in or out, and the officers use the computer to chart the course. You can see us on the chart – the little green boat.

navigation chart

This is a chart zoomed in. The green boat (center) is us, and the blue line and dot is our heading.

In the chart above, you’ll see that we seem to be off course. Why? Most likely because of that other ship that is headed our direction. We talk to them over the radio to get their intentions, and reroute our course accordingly.

navigation chart 2

Notice the left side, where it says “dump site (discontinued) organochlorine waste. There are a lot of these type dump sites in the Gulf. Just part of the huge impact humans have had on our oceans.

When we get close to a station, as in the first picture above, the bridge watch team sets up a circle with a one mile radius around the location of the station. See the circle, upper center? We need to stay within that circle the whole time we are collecting our samples. With the bongos and the neuston net, the ship is moving slowly, and with the CTD the ship tries maintain a stationary position. However, wind and current can affect the position. These factors are taken into account before we start the station. The officer on the bridge plans out where to start so that we stay within the circle, and our gear that is deployed doesn’t get pushed into or under the boat. It’s really a matter of lining up vectors to figure it all out – math and physics at work. But what is physics but an extension of common sense? Here’s a close-up:

setting up for station

Here is the setup for the station. The plan is that we will be moving south, probably into the wind, during the sampling. See the north-south line?

How do those other ships appear on the chart? This is through input from the AIS (Automated Information System), through which we can know all about other ships. It broadcasts their information over VHF radio waves. We know their name, purpose, size, direction, speed, etc. Using this and the radar system, we can plan which heading to take to give the one-mile distance that is required according to ship rules.

As a backup to the computer navigation system, every half hour, our coordinates are written on the (real paper) navigation chart, by hand.

Pete charting our course

ENS Pete Gleichauf is writing our coordinates on the paper navigation chart.

There are drawers full of charts for everywhere the Gunter travels!

Melissa and the nav charts

ENS Melissa Mathes showing me where all the navigation charts are kept. Remember, these are just backups!

Below is our radar screen. There are 3 other ships on the screen right now. The radar computer tells us the other vessels’ bearing and speed, and how close they will get to us if we both maintain our course and speed.

radar screen

The other vessels in the area, and their bearing, show up on the radar.

If the radar goes down, the officers know how to plot all this on paper.

maneuvering board

On this maneuvering board, officers are trained to plot relative positions just like the radar computer does.

Below is Dave showing me the rudder controls. The rudder is set to correct course automatically. It has a weather adjustment knob on it. If the weather is rough (wind, waves, current), the knob can allow for more rudder correction to stay on course. So when do they touch the wheel? To make big adjustments when at station, or doing course changes.

rudder controls

Dave’s arm – showing me the rudder controls.

These are the propulsion control throttles – one for each propeller. They control the propeller speed (in other words, the ship’s speed).

propeller speed throttles

Here are the throttles that control the engine power, which translates to propeller speed.

bow thruster control

This controls the bow thruster, which is never used except in really tight situations, such as in port. It moves the bow either direction.

And below is the Global Maritime Distress and Safety System (GMDSS). It prints out any nautical distress signal that is happening anywhere in the world!


Global Marine Distress and Safety System

And then, of course, there is a regular computer, which is usually showing the ships stats, and is connected to the network of computers throughout the ship.

checking the weather

ENS Kristin Johns checking the weather system coming our way.

In my post of March 17, I described the gyrocompass. That is what we use to determine direction, and here is a rather non-exciting picture of this very important tool.


This is the gyrocompass, which uses the rotation of the Earth to determine true north.

As you can see, we have two gyrocompasses, but since knowing our heading is probably the most important thing on the ship, there are backup plans in place. With every watch (every 4 hours), the gyro compass is aligned the magnetic compass to determine our declination from true north. Also, once per trip, the “gyro error” is calculated, using this nifty device:


This is called the alidade. Using the position of the sun as it rises or sets, the gyro error can be computed and used to keep our heading perfectly accurate.

The reading off of the alidade, combined with the exact time, coordinates, and some fancy math, will determine the gyro error. (Click on a picture to see full captions and full size pictures.)

You can see that we have manual backups for everything having to do with navigation. We won’t get lost, and we’ll always know where we are!

driving the ship

Here I am, “driving” the ship! Watch out! Photo by ENS Pete Gleichauf

Back to Plankton!

These past two days, we have been in transit, so no sampling has been done. But here are a couple more cool micrographs of plankton that Pam shared with me.

invertebrate plankton

This picture shows several invertebrates, along with fish eggs. Madalyn and Andy, who are invertebrate people, got excited at this collection. The fat one, top left is a Doliolid. The U-shaped one is a Lucifer shrimp, the long one in center is an amphipod, at the bottom is a mycid, etc. There are crabs in different stages of development, and the multiple little cylinders are copepods! You can also see the baby fish inside the eggs. Photo credit Pamela Bond/NOAA

red snapper larvae

These are larval red snapper, a fall spawning fish species of economic interest. Notice the scale! You have to admit baby fish are awfully cute. Photo credit: Pamela Bond/NOAA

Interesting Fish Facts

Our main fish of interest in the winter plankton sampling are the groupers. There are two main species: gag groupers and red groupers. You can learn all about them on the NOAA FishWatch Website. Groupers grow slowly and live a long time. Interestingly, some change from female to male after about seven years – they are protogynous hermaphrodites.

red grouper

Red grouper. Image credit: NOAA

In the spring plankton research cruise, which goes out for all of May, the main species of interest is the Atlantic bluefin tuna. This species can reach 13 feet long and 2000 lbs, and females produce 10 million eggs a year!

school of bluefin tuna

School of Atlantic bluefin tuna. Photo credit: NOAA

The fall plankton research focuses on red snapper. These grow up to about 50 pounds and live a long time. You can see from the map of their habitat that it is right along the continental shelf where the sampling stations are.

red snapper

Red snapper in Gray’s Reef National Marine Sanctuary. Image credit: NOAA

The NOAA FishWatch website is a fantastic resource, not only to learn about the biology, but about how they are managed and the history of each fishery. I encourage you to look around. You can see that all three of these fish groups have been overfished, and because of careful management, and research such as what we are doing, the stocks are recovering – still a long way from what they were 50 years ago, but improving.

I had a good question come in: how long before the fish larvae are adults? Well, fish are interesting creatures; they are dependent on the conditions of their environment to grow. Unlike us, fish will grow throughout their life! Have you ever kept goldfish in an aquarium or goldfish bowl? They only grow an inch or two long, right? If you put them in an outdoor pond, you’ll see that they will grow much larger, about six inches! It all depends on the environment (combined with genetics).

“Adult” generally means that they are old enough to reproduce. That will vary by species, but with groupers, it is around 4 years. They spawn in the winter, and will remain larvae for much longer than other fish, because of the cooler water.

Personal Log

I’ve used up my space in this post, and didn’t even get to tell you about our scientists! I will save that for next time. For now, I want to share just a few more pictures of the ship. (Again, click on one to get a slide show.)


Terms to Learn

What is the difference between a nautical mile and a statute mile? How about a knot?

Do you know what I mean when I say “invertebrate?” It is an animal without a backbone. Shrimp and crabs, are invertebrates; we are vertebrates!

8 responses to “Julia West: This Is What Drives Us, April 1, 2015

  1. Hi Julia,
    Very nice April fools joke! What is the circular thing in the window above the throttles? Also, what kind of ships do you encounter in the gulf?

  2. Glad you liked it, Ryan! So that circular thing is a heater. There are a couple of heated windows. Certainly aren’t needed here, but this ship spends time in the North Atlantic, and if there’s ice forming on the windows, it’s nice to be able to see something! Last April we had a late spring in the northeast, and the Gunter was in the North Atlantic and got caught in 110 mile an hour winds and 40 ft seas. No thank you!
    Oil tankers go through here, from Galveston, cargo ships go to Houston, today we saw a Coast Guard cutter, stuff like that. It’s been quiet the past few days – very few oil rigs and ships – we must have been out of the main shipping lanes. I think someone (you?) actually asked this question before and I answered it! We’ll be in port in the morning!

  3. Hi Julia,
    I liked the April Fool’s joke – it would have been cool if you actually had caught a giant squid! Could the types of squid you catch, given enough time, grow into giant squid (are they the larval version of giant squid)? In answer to your question, a statute mile is a unit of measure used on land (it’s what we call just ‘a mile’), while a nautical mile is a unit of measure used at sea. A statute mile is equal to 5,280 feet, and a nautical mile is equal to about 6,076 feet. A knot is a unit of speed equaling one nautical mile per hour. The pictures of all the different fish were cool – the larval versions of the red snapper look so different from the adults! I hope you are having a good time on the voyage!

  4. Our round heated windows are a type called Clearview. They are both heated and motorized. They spin very fast and throw the water off to the edge of the circle. I wonder if anyone else knows the physics behind how these window work.

  5. Nice job, Jamie! No, giant squid don’t live around here. There are many types of squid, and I don’t profess to know much about them at all, except I’m not thrilled about calimari!

  6. Hi Julia. Did you learn a lot on the plankton research?
    What does the USS Cole have to do with the plankton research? The USS Cole is a very interesting ship.

  7. Hi Emalie, I certainly learned a lot – I’m hoping you did too. Do you think you did? If you read the blog post of 3/27, you’ll see what the USS Cole has to do with plankton research. It’s about the people you meet.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s