Meg Stewart: Data Acquisition on a Small Boat: Tips and Tricks, July 14, 2019

NOAA Teacher at Sea

Meg Stewart

Aboard NOAA Ship Fairweather

July 8 – 19, 2019


Mission: Cape Newenham Hydrographic Survey

Geographic Area of Cruise: Bering Sea and Bristol Bay, Alaska

Date: July 14, 2019

Weather Data from the Bridge
Latitude: 58° 36.7 N
Longitude: 162° 02.5 W
Wind: 9 knots SE
Barometer: 1005.0 mb
Visibility: 10 nautical miles
Temperature: 61° F or 15.5° C
Weather: Overcast with fog, no precipitation

Fairweather in fog
The other day while on a survey launch, we came up on the Ship Fairweather as fog was rolling in.


Science and Technology Log

Launch preparation
A launch getting ready to survey. The setup process takes some time and all of the preparation is necessary for accuracy in the data.
Heave, pitch, roll, and yaw describe the movements of a boat (or a plane). An inertial measurement unit reads those discrete movements. Source: wikipedia

In the last post I talked about hydrographic surveying, the software used and the multibeam echosounder on the survey boats (called launches). The software is setup in the cabin by the hydrographer in charge. It takes a good five minutes to get an accurate read from the GPS (global positioning system) receiver. Then it takes time for the IMU (inertial measurement unit) to respond and start to read the boat’s heave, pitch, roll, yaw, and heading values. 

hydrograpers
The hydrographer in charge (standing) is showing the hydrographer in training (seated) how to setup the day’s survey project using the echosounder software.
launch data storage
The four Fairweather launches have the same, high-end technology in their cabins used to collect data from the multibeam echosounder, CTD sensor, a sound speed system, and a positioning and altitude system.

Often, the launch drives in a circle eight in order for the positioning receivers to be “seen” by the satellites, as a  stationary object is more difficult to detect than one that is moving. Setting up the day’s project using the multibeam echosounder software also takes some time but all the steps need to be done properly and to the correct specifications prior to starting the sounder. If not, the locational data will be wildly off and the depths inaccurate.

Another task that must be done from the launch before starting to transect is to test the salinity and water temperature using a CTD probe, which is called a cast. I mentioned this in a previous post. CTD stands for conductivity, temperature and depth. In the general area where the launch will survey, the CTD drops slowly to the bottom of the seafloor, collecting data that will be fed into the hydrographic program. Salinity and temperature at different depths will slightly change the rate at which sound travels in water. Again, the CTD process makes the location and depths as accurate as possible and must be done.

Meg casts CTD probe
Casting the CTD probe into the survey location to get conductivity, temperature and depth readings.

Usually, the chief hydrographer sets the defined area to be transected for the day and this is usually a polygon. The launch will sweep with the multibeam echosounder the outside lines and then scan at parallel set distances between the lines, either in a roughly north-south direction or a roughly east-west direction. For this particular hydrographic project, coverage of survey lines can be spaced at about 400 meters apart or greater apart depending on the depth. Recall that the nautical chart of Bristol Bay from the last post showed soundings dotting the area. Solid bathymetric coverage is not always needed on these projects. The Cape Newenham area has proven to have gradually varying depths and is mostly quite flat so free from obvious obstructions like large boulders and sunken ships. 

Once the technology setup is complete in the cabin, the hydrographer shares the map window with the coxswain (the person in charge of steering or navigating the boat). The hydrographer sets the points and the lines so that the coxswain knows where to direct the launch. And by direct, I mean the coxswain uses compass direction and boat speed to get from place to place for the survey. And the hydrographer in charge turns the echosounder on and off when the launch is in position or out of position.

Coxswain
The coxswain navigates the survey line set by the hydrographer in charge.

Because the transects run parallel to each other and are equally spaced apart, the hydrographers call this technique “mowing the lawn,” (see video below) for they are essentially mowing the surface of the ocean while the multibeam echosounder is collecting soundings of the surface of the seafloor.

A video of someone mowing a lawn on a riding lawnmower

A day out on a launch will go from about 8:30am to about 4:30pm but sometimes an hour or so later. If the Alaskan weather is cooperating, the hydrographers want to do as much as they can while out on the launch. Once surveying is complete for the day, the hydrographer in charge has to close up and save the project. Then data get transferred to the larger workstations and shared drive on the Fairweather.

Meg on launch
Every day on the launch, at least on this leg, has been great with perfect weather. And today, the added bonus for me was the phenomenal geology as we surveyed right along the shore.


Personal Log

I’ve taken loads of photos and video while at sea. I have tried to post just those pictures that help explain what I’ve been trying to say in the text. I haven’t posted any video on here as the internet on the ship is very weak. These next photos are a tour of different parts of the NOAA Ship Fairweather.

  • view of the bridge 1
  • view of the bridge 2
  • view of the bridge 3
  • barometer

The above slide show gives an idea of what the bridge is like. The ship is steered from the bridge. All the navigational instruments and weather devices, among other tools, are found on the bridge.

emergency billet
These emergency billets are for me, TAS Stewart, Meg, and it’s posted on my door. For each emergency situation, Fire, Abandon Ship, or Man Overboard, there is a bell sound and the location on the ship where I am to muster. Life at sea is all about being ready for anything.
mess
This is the mess (where we eat. And eat. And eat!) The food is fantastic but I’ve gained some pounds for sure.
Ice cream spot
Maybe this is why. Sometimes the Ice Cream Spot looks like this. Ha!
The galley
The galley
Laundry
Laundry machines available and detergent is supplied. No need to bring all your clothes. Also, sheets and towels are supplied.
Stairs
Stairs are called ladders on a ship. Makes sense to me – they’re often pretty steep. You must always hold a rail.
The Lounge
The Lounge
DVD collection
DVD collection of over 500 films
Lounge full of people
Yes, so this is the lounge and there can be meetings in here, training, movies, games, puzzles, quiet space, etc.
DVD in stateroom
Or, you can pop a DVD into a player in the Lounge, go back to your stateroom and watch. Or fall asleep. This is the original Blade Runner (which I never saw) and which I didn’t care for.
Finer things
The good folks of Ship Fairweather like to have a nice time every now and again, so they set up evenings, about once a leg, to have Finer Things. People come by, bring fine cheeses, fine chocolates, fine almonds, fine fig jelly, and fine maple sugar candy from Rhinebeck, NY, and have a fine time. And a disco ball.


Did You Know?

Inertial Measurement Units (IMU) technology that is so important for accurate hydrographic survey mapping was developed by the U.S. military. IMUs were used in the development of guided missiles, unmanned aerial vehicles (and now drones), battlefield reconnaissance, and target practice.

Quote of the Day

“A ship in port is safe, but that’s not what ships are built for.” – Grace Hopper

Lona Hall: Rockin’ at the NALL on Ugak, June 10, 2019

NOAA Teacher at Sea

Lona Hall

Aboard NOAA Ship Rainier

June 3 – 14, 2019

Mission: Kodiak Island Hydrographic Survey

Geographic Area of Cruise: Kodiak Island, Alaska

Date: June 10, 2019

Time:  1932 hours

Location: Saltery Cove, Kodiak Island

Weather from the Bridge:

Latitude: 57°29.1359’ N

Longitude: 152°44.0488’ W

Wind Speed: 17.2 knots

Wind Direction: N (353 degrees)

Air Temperature: 12.13° Celsius

Water Temperature: 9.44° Celsius

Lona on a launch vessel
Sitting in the sun on a launch, Rainier in the background


Science and Technology Log

For my second time out on a launch, I was assigned to a shoreline survey at Narrow Cape and around Ugak Island (see chart here).  Survey Tech Audrey Jerauld explained the logistics of the shoreline survey.  First, they try to confirm the presence of charted features (rocks) along the shore. (As you may remember from my last post, a rock is symbolized by an asterisk on the charts.) Then, they use the small boat’s lidar (LIght Detection And Ranging) to find the height of the rocks. Instead of using sound pulses, as with sonar, lidar uses pulses of laser light.  

Point Cloud
Point Cloud: Each dot represents a lidar “ping”, indicating the presence of features above the waterline

Once a rock was identified, Audrey photographed it and used the laser to find the height of the rock to add to the digital chart.  The launch we used for the shoreline survey was RA-2, a jet boat with a shallow draft that allows better access to the shoreline. We still had to be careful not to get too close to the rocks (or to the breakers crashing into the rocks) at certain points around Ugak Island.  The line parallel to the shore beyond which it is considered unsafe to survey is called the NALL (Navigable Area Limit Line). The NALL is determined by the crew, with many factors taken into account, such as shoreline features, marine organisms, and weather conditions.  An area with many rocks or a dangerously rocky ledge might be designated as “foul” on the charts.

Amanda and Audrey
Amanda and Audrey discussing the locations of rocks along the shoreline

I must pause here to emphasize how seriously everyone’s safety is taken, both on the small boats and the ship itself.  In addition to strict adherence to rules about the use of hard hats and Personal Flotation Devices in and around the launches, I have participated in several drills during my stay on the ship (Man Overboard, Fire and Emergency, and Abandon Ship), during which I was given specific roles and locations.  At the bottom of each printed Plan of the Day there is always a line that states, “NEVER shall the safety of life or property be compromised for data acquisition.” Once more, I appreciate how NOAA prioritizes the wellbeing of the people working here. It reminds me of my school district’s position about ensuring the safety of our students.  No institution can function properly where safety is not a fundamental concern.


Career Focus – Marine Engineer

Johnny Brewer joined the Navy in 1997.  A native of Houston, Texas, many of his family members had served in the military, so it seemed natural for him to choose a similar path after high school.  The Navy trained him as a marine engineer for a boiler ship. Nearly 15 years later he went into the Navy Reserve and transitioned to working for NOAA.

Johnny Brewer, Marine Engineer
Johnny Brewer, Marine Engineer

Working as an engineer requires mental and physical strength.  The Engineering Department is responsible for maintaining and updating all of the many working parts of the ship–not just the engine, as you might think! The engineers are in charge of the complex electrical systems, plumbing, heating and cooling, potable water, sewage, and the launches used for daily survey operations.  They fix everything that needs to be fixed, no matter how large or small the problem may be.

Johnny emphasized how important math is in his job.  Engineers must have a deep understanding of geometry (calculating area, volume, density, etc.) and be able to convert measurements between the metric and American systems, since the ship’s elements are from different parts of the world.  He also described how his job has given him opportunities to visit and even live in new places, such as Hawaii and Japan. Johnny said that when you stay in one place for too long you can become “stuck in a box,” unaware of the world of options waiting for you outside of the box.  As a teacher, I hope that my students take this message to heart.


Personal Log

In my last post I introduced Kimrie Zentmeyer, our Acting Chief Steward. In our conversation, she compared the ship to a house, the walls of which you cannot leave or communicate beyond, except by the ship’s restricted wi-fi, while you are underway.  I would like for my readers (especially my students) to imagine living like this, confined day in and day out to a single space, together with your work colleagues, without family or friends from home.  How would you adjust to this lifestyle? Do you have what it takes to live and work on a ship? Before you answer, consider the views from your back porch!

Ugak Bay
Ugak Bay (Can you spot the whale?)


Word of the Day

bulkhead – a wall dividing the compartments within the hull of a ship

Q & A

Are there other NOAA ships working in Alaska?

Yes!  NOAA Ship Fairweather is Rainier’s sister-ship and is homeported in Ketchikan, Alaska.  Also, the fisheries survey vessel, NOAA Ship Oscar Dyson is homeported in Kodiak, not far from where we are currently located.

What did you eat for dinner?

This evening I had sauteed scallops, steamed broccoli, and vegetable beef stew. And lemon meringue pie. And a cherry turnover. And ice cream.

(:

Brandy Hill: Chat with Chief Engineer and My First Tuna Catch, June 28, 2018

 

NOAA Teacher at Sea

Brandy Hill

Aboard NOAA ship Thomas Jefferson

June 25, 2018 – July 6, 2018

 

Mission: Hydrographic Survey- Approaches to Houston

Geographic Area of Cruise: Gulf of Mexico

Date: June 28, 2018

 

Weather Data from the Bridge

Latitude: 28° 50.7’ N

Longitude: 093° 34.4’ W

Visibility: 10+ nm

Sky Condition: 4/8

Wind: 12 kts

Temperature:

Sea Water: 29.6° C

Air: 29.3° C

 

 

Science and Technology Log

This afternoon I spent an hour with Chief Marine Engineer, Thom Cleary. As promised, he gave me a tour of the Engine Room. Thom arrived on the Thomas Jefferson in 2011 and has worked not only on maintaining operations, but greatly improving them. When asked about his favorite ship mechanism, he responded with one that is not his favorite but of which he is most proud. The Thomas Jefferson, along with most other ships, typically used to rid greywater and sewage by offloading into the ocean. The EPA states that ships must be at least one nautical mile from land or people in the water and three nautical miles from aquaculture (2018). With hydrographic survey operations taking place in “no discharge” areas (close to shore), this could complicate and/or slow down the Thomas Jefferson’s progress.

Realizing the inefficiency and in an effort to improve, Thom investigated other options. It was decided that a fuel storage tank would be converted to hold more wastewater. After a long wait period, the new method was installed. Within the first season 38,000 gallons of sewage was stored and discharged to a shore treatment facility. Today, the tanks have gone almost two months without release into the Gulf of Mexico. This improvement has allowed hydrographic operations to continue without interruption, conserves fuel, and increases efficiency.

Renovations to the Thomas Jefferson did not stop there. Originally constructed in 1991, the ship has room for many other improvements. Thom and team advocated for all natural lubricants (rather than petroleum), switched all light fixtures to LEDs, and adjusted the ballast system. In 2016 the roughly 122,000 gallon ballast system changed from using sea to municipal water. This now allows the ship to move from multiple coastal waters without concern for carrying invasive species in the ballast tanks. In addition, the new waste water tank was strategically placed in the center of the ship to help with stability.

Ballast diagram

Ballast diagram showing invasive species risk. (CC)

Thom is an innovator and self-described incorrigible tinkerer. Many of these changes would not have been made without his (and team’s) desire and advocacy to make things better. When I asked if these upgrades were standard on ships, he mentioned that the Thomas Jefferson is a trailblazer.

Chief Engineer Thom Cleary

Chief Engineer Thom Cleary and the desalination/ reverse osmosis system. The RO typically operates at 650 psi (with 900psi maximum potential) and pushes sea water through a membrane creating potable water for the ship.

 

Personal Log

CO (Commanding Officer) authorized a launch on one of the boats. After some mishaps with a fuse, the crew performed multiple safety checks and we were cleared to go. Mission: collect survey data near a stationary platform. CO’s comfort level to obstructions with the main ship is a half-mile, so having the smaller launch boats is helpful when surveying areas like this.

Launch Boat Approach

The launch boat crew from left to right: Lt. Klemm, Kevin Brown, Pat Osborn, and Brandy Hill (below deck).

 

SurveyNearPlatform

Survey area near the stationary platform. The ship to the left is a supply vessel.

While cruising out to the survey area, I spoke with Pat Osborn, part of the Thomas Jefferson’s deck crew and our survey line driver for the day. Pat has two years of training and was explaining that he is still learning parts of his job. (Everyone on the ship wears multiple hats.) He spoke highly of his job and appreciated the multi-dimensional relationship between CO and the crew. Pat explained that CO is not expected to be an expert in all areas of the ship- there are safety checks (such as preparing for the launch) where the CO asks lead crew members to evaluate and sign-off prior to action. Every mission I’ve observed and attended has proceeded in this manner. It is a highly respectful and safe environment.

AllisonLaunchApproach

Chief Survey Technician, Allison Stone, awaiting launch boat arrival.

Launch Return to Ship

Patrick Osborn approaching ship Thomas Jefferson with the launch boat.

KevinDeployingCTD

Kevin Brown lowers the CTD while the boat is stationary. A CTD captures the salinity, temperature, depth, and concentration of particles in the water column. This information is used for analyzing the survey data. On the ship, this information is collected using an MVP which allows the ship to stay in motion.

As soon as we had the survey equipment set up and running, survey technician Kevin Brown brought out a fishing pole. I hadn’t realized that we could fish while out on the boat! We proceeded to catch and release about 10 tuna (likely False Albacore and Bonito). Kevin reeled in two, then passed the pole to me. I couldn’t believe how hard it was to real in a fish. I was reading that they can stay on the line and swim up to 40 mph!

Brandy reeling

Brandy Hill’s active line power stance.

False Albacore

Brandy Hill and her first fishing boat catch, False Albacore.

Peaks

 + Witnessed hard work and precision paying off- the launch boat survey data had an error of 0.0006 meters. The data is highly accurate!

+ Drove “the survey line” on the launch boat. (More of an explanation coming soon.)

+ Reeled in a beautiful, tough fish.

Note: After the seasickness subsided, I’ve decided to leave out the “Valleys” category. I’m having a great time.