coxswain – NOAA Teacher at Sea Blog

June 29, 2026June 29, 2026

Jennifer Widdig: On the Front Lines of Charting, June 29, 2026

view from an upper deck of NOAA Ship Thomas Jefferson as a small launch vessel approaches for docking

NOAA Teacher at Sea

Jennifer Widdig

Aboard NOAA Ship Thomas Jefferson

June 17 – June 30, 2026

Mission: Hydrographic Survey
Geographic Area of Cruise: Lake Erie and Lake Ontario
Date: Monday, June 29, 2026

Weather Data from the Bridge

Latitude: 043^o15’N
Longitude: 077^o22’W
Sky Conditions: Sunny
Visibility: >10miles
Wind Speed: 1 knots
Dry Bulb: 19^oC
Wet Bulb: 18.5^oC

Science and Technology Log

Jen takes a selfie from the railing of a small launch vessel, angled so that we can see NOAA Ship Thomas Jefferson in the background at some distance. She wears a green hard hat and orange life vest. The sky is blue with only a few low white clouds, and the water is bright teal with some low waves. — Out on boat 2904 with NOAA Ship *Thomas Jefferson* in the background

One of the highlights of this leg was getting the opportunity to spend a day aboard survey launch 2904. Junior Officer Julian Santos served as our coxswain, while Senior Survey Technician Ali DiTommaso managed the survey equipment. It was a great opportunity to experience how NOAA conducts nearshore hydrographic surveys and to see firsthand the challenges of collecting data in shallow water.

Our mission for the day was to locate the 15-meter depth contour on our assigned survey sheet. Using the multibeam sonar, the display was configured so that anything shallower than 15 meters appeared black. As we “painted” the seafloor with the multibeam, we watched for that black boundary. Once we reached the 15-meter contour, we stopped collecting multibeam data in that area and moved on to find the next section of the contour. Eventually, we connected these sections to create a continuous 15-meter line across the sheet.

photo of a computer screen displaying multibeam data from the small launch vessel. the large portion of the screen shows the depth of the area, color coded; anything shallower than 15 m is shown in dark gray. — Multibeam data from boat 2904

After establishing the contour, we switched to side-scan sonar to survey the area shallower than 15 meters. Because side-scan sonar can cover a much wider swath of the seafloor than the multibeam, our survey lines were spaced farther apart, allowing us to efficiently search for underwater features and potential hazards. During our survey we operated the 75-meter side-scan system in water depths ranging from approximately 7 to 15 meters. We did not have the opportunity to switch to the 50-meter side-scan configuration, which is typically used in even shallower water, from about 4 to 8 meters.

phot of a computer screen displaying sidescan data. the center of the bathymetric map is a vertical black band, representing the track of the small vessel, which cannot collect data directly beneath it with the side-scan sonar. to the left and right of this band is detailed data showing the bumpy surface of the lake bottom. — Getting side-scan data from boat 2904

Working from a small survey launch requires constant multitasking. Since it was the weekend, recreational boat traffic was heavy, requiring extra vigilance while navigating and collecting data. Unlike aboard the ship, the launch crew must solve many equipment issues on their own or troubleshoot with assistance over the phone. At one point, our air conditioning stopped working. Although it certainly made for a warm day, it did not affect the safety of the operation, so we continued surveying.

view of the survey station on board a small vessel. inside the boat's cabin, facing ahead, a desk surface surrounds a single captain's chair. We can see three computer monitors. A survey tech in a purple t-shirt sits facing the computers (away from the camera.) — Ali DiTommaso manning the survey station on boat 2904

Although the surveying stops when the launch returns to the ship, the work is far from over. Every evening, the survey data is processed so it can be evaluated before the next day’s operations. During this process, the survey technicians apply the sound velocity information collected from the Sea-Bird CTD casts. Because sound travels at different speeds depending on the water’s temperature, salinity, and pressure, these measurements are essential for accurately calculating the depth of the seafloor.

The data is also corrected using the vessel’s position, motion, and orientation throughout the survey. Every pitch, roll, heave, and heading change of the launch is accounted for so the seafloor is mapped in its true position rather than being distorted by the boat’s movement. Water level corrections are also applied to account for changes in lake level during the survey.

a zoomed-in view of a nautical chart showing a portion of the southern coastline of Lake Ontario in beige and the water of the lake in blue. There are contour lines at 3 m, 5 m, 7 m drawn extending away from shore. Elsewhere, floating numbers represent depths as deep as 69 m. In a boxed off section of the chart, color coded shading indicates the depths of an entire swath surveyed by NOAA Ship Thomas Jefferson, with lime green indicating about 15 m deep and darker blue indicating about 23 m deep. — Processed data for the sheet that Boat 2904 has been working on

Once these corrections have been made, the software combines the overlapping survey lines and “smooths” the edges between them to create a continuous, high-quality map of the seafloor. Processing also helps identify any holidays, small gaps where little or no data was collected. If holidays or other data quality issues are found, the area will need to be resurveyed before the sheet can be considered complete.

survey data (shading, color coded by depth) overlaid on a section of a nautical chart of a portion of Lake Ontario. some areas are shaded in rectangles; some are wide diagonal lines showing the survey data collected as the ship transited from one place to another — Total amount of processed data for this leg of NOAA *Thomas Jefferson*

Personal Log

Jen poses for a photo with a man in a navy sweatshirt and a woman wearing a large headset over years. They are inside the cabin of the small launch vessel. — Coxswain Junior Officer Julian Santos, Senior Survey Technician Ali DiTommaso, and myself aboard boat 2904

Going out on a survey launch was one of the highlights of my time aboard NOAA Ship Thomas Jefferson. I already love being out on the water, so I knew my biggest challenge wouldn’t be seasickness but trying not to be rocked to sleep! The water was calm, with waves less than a foot high, something the crew was very thankful for, even if I secretly wouldn’t have minded a little more excitement.

After boarding 2904, we were lowered over the side of the ship. I followed Senior Survey Technician Ali DiTommaso onto the bow, where she released the locking clamps that connected us to the davit. It was fascinating to watch how smoothly the process worked and to finally experience a launch from the small boat perspective.

Jen sits at the helm of the small launch vessel, her left hand on the wheel, and turns her head to smile for a photo — Taking a turn at the wheel on boat 2904

We spent the day on the water from about 6:30 a.m. until 3:30 p.m. The launch may be much smaller than the ship, but it is surprisingly well equipped. We brought water, hot water for tea, breakfast, and snacks, and there was even a small refrigerator stocked with sandwich supplies and a microwave for lunch. It felt like a tiny floating office.

With Junior Officer Julian Santos serving as coxswain and Ali running the survey operations, I jokingly felt like the “passenger princess” for the day. While they handled the work, I had the opportunity to observe every aspect of the survey. Seeing hydrography on a smaller scale helped me better understand the process.

view from a distance of a small launch vessel approaching NOAA Ship Thomas Jefferson — Boat 2903 getting ready for recovery by NOAA Ship *Thomas Jefferson*

One of the most impressive moments came at the end of the day during recovery. Watching the coxswain carefully maneuver alongside the TJ looked effortless, but I quickly realized how much coordination is required. The engineers stand by in case there are any issues with the davit or the launch, the Bosun operates the davit, crew handle the lines, and the entire evolution is supervised by the Commanding Officer and Executive Officer. Meanwhile, the bridge monitors everything from the bridge wing to ensure the recovery is completed safely and efficiently.

view from an upper deck of NOAA Ship Thomas Jefferson of the recovery of a small launch vessel. The small vessel has pulled up alongside the large ship, and two davit arms with cables are lowering toward the boat. seven crewmembers with hard hats stand distributed around the two davits, read to help bring the small boat aboard. we can see other crewmembers watching the operation from higher decks. — Boat 2904 being recovered by the crew of NOAA Ship *Thomas Jefferson*

Before I had the chance to ride on one of the launches, I had watched them return to the ship from the deck. Seeing the boats racing across the water toward the TJ with spray flying behind them reminded me of something straight out of an old James Bond movie. They looked fast, powerful, and just a little dramatic. It felt like they were in slow motion!

Santos and Ali really made the day great, and I was lucky enough to get to tag along with them!

Did You Know?

The Great Lakes span 4,530 miles of coast and account for 21% of the world’s freshwater, with more that 30 million people relying on them for drinking water.
The nautical term “holiday” comes from the 17th century when missing a spot while painting a ship. “Were you on a holiday?” or “Do you need a holiday?”

July 27, 2023July 27, 2023

Elli Simonen: Survey Launches, July 24, 2023

NOAA Teacher at Sea

Elli Simonen (she/her)

Aboard NOAA Ship Fairweather

July 10, 2023 – July 28, 2023

Mission: Hydrographic Survey of the Pribilof Islands

Geographic Area of Cruise: Pribilof Islands, Alaska

Date: July 24, 2023

Weather Data

Location: 56°36.8259’N,169°32.2224’W

Outside temperature: 11°C

Water temperature: 10°C

True Winds: 16kn, 185.4°

Skies: Foggy with Drizzy Rain

Visibility: 5nmSea

Wave: 1-2 ft

Swell Wave: 1 ft

Science and Technology Log

We are currently at anchor off the north shore of Saint George Island and the survey launches are going out daily to survey a portion of the surrounding waters. I have been on the survey launches twice, each time surveying a different area.

Survey Launch July 22, 2023

The Pribilof Islands are the breeding grounds for more than two thirds of the world’s fur seal population and their numbers peak in July. Our surveying operations do their best not to disturb the Fur Seals. I was on a launch that was assigned the harbor. However, upon entering, we saw a colony of Fur Seals and had to turn back around. We then went onto survey another area in open water. Later that morning, the winds increased and all survey launches returned to the ship out of caution for the weather.

view over the edge of a survey launch vessel of the harbor on a small island. it's a cloudy day, and the sky, trees, and water are all shades of blue-gray. the only color comes from the bright orange life ring mounted on the vessel.

Entering the harbor at Saint George

view at a distance of fur seals swimming near the shore of St George island. the fur seals appear as small dark shapes poking out from the water. the land is covered in large gray boulders.

Fur Seals in the Saint George harbor

Survey Launch July 23, 2023

We went out to survey an area closer to shore and were out all day – a good weather day. We surveyed using set lines; this is where survey lines are parallel and evenly spaced apart. During post survey data processing, these lines of coverage will be used to update soundings on the chart. Set lines are used in areas of shallow water where there is not much bathymetric data, such as the Pribilof Islands. This process allows the survey team to complete a larger survey area in less time.

Our surveying boundary close to shore is defined by the navigational area limit line (NALL), which is the distance from shore that vessels can reasonably navigate. The other boundaries are mapped out by the survey team ensuring coverage of the entire area. During surveying in addition to depth data, any information about features that can impact navigation need to be noted. This can include an outcrop of rocks, shipwrecks or a kelp forest. We did see a kelp forest close to the shoreline during this survey, and indicated that in our data. Kelp forests can increase or decrease in size depending on the year and water temperature, but generally stay in the same place.

The swath is the width of the survey lines. During surveying the swath gets larger as the depth increases. In this survey, as you move away from shore the depth becomes deeper, so the width of the swath increases as well. This is due to the fact that the MBES angle is fixed and the depth is related to the swath by the tangent function.

photo of a computer screen showing, in a large window, a map of the survey area. black lines surrounded by swaths of bright red, green, or yellow bands of color snake up and down the map, representing the transects surveyed.

Screen showing the set line spacing and data taken near the shore.

cliffs along the shore of St George, as seen from a survey launch. the water is turquoise-colored in the foreground and brownish closer to shore. tall cliffs of black, brown, and gray colors, with some green growth at higher points, rise out of the photo. there are white specks - the seabirds - all over the cliffs.

Close to the shoreline of Saint George. The color change of the water indicates a kelp forest. Thousands of sea birds are on the cliffs.

calculations on a whiteboard. at top is a simple depiction of a boat, labeled 'launch.' a triangle extends down from the bottom of the launch toward the seafloor. the top angle (between the lines extending from the launch) is labeled 130 degrees. arrows show the direction of the echosounder pings (labeled MBES) toward the seafloor. The height of the triangle is labeled "depth" and the base "width of the swath."
Below this image is a drawing of a right-angle triangle, one half of the above. The top angle is labeled 65 degrees (half of 130 degrees), the height is labeled "Depth" and the base is labeled "1/2 swath."
written calculations read: tan (theta) = opposite side length / adjacent side length. tan 65 degrees = (1/2 swath)/depth. (depth)(tan 65 degrees) = 1/2 swath. 2 (depth)(tan 65 degrees) = swath. 2(depth)(~2.1) = swath, ~4.2 (depth) = swath.

How the width of the swath can be calculated.

TAS Elli Simonen on a survey launch close to shore of Saint George, one of the Pribilof Islands

At the Helm of the Survey Launches

Coxswains are responsible for steering and navigating the survey launches. They use a variety of instruments and sensors to maintain safety and guide the survey launches over the planned survey lines. The heading is the direction the bow of the ship is pointing, expressed as a degree measurement from 0° to 360°. We were mainly surveying lines that were running north-south and the heading measurement was 0° when we went north and 180° south.

a small black instrument panel showing the heading, currently 002.0 (close to 0).

Heading indicator showing the direction of the survey launch and allows for autopilot.

a compass mounted to a surface on the survey launch. it reads close to 0 N.

Magnetic Compass showing heading on the survey launches.

photo of a computer screen showing a map of the survey area

Screen for coxswains on survey launches showing depth, the water column and survey lines.

two people at the helm of the survey launch vessel. Elli grips the helm while Ashley looks on. we can see gray ocean surface out the windows. the compass is mounted to the dashboard above the helm.

TAS Elli Simonen attempting to steer the Survey Launch with NOAA Corps member ENS Ashley Howell. It is much harder than it looks!

Personal Log

Day to Day

Most of my days have been spent on the ship or lately, on survey launches. If I’m on the ship, I usually spend most of the day in the survey room with the survey technicians. Breakfast is served from 7-8 am, lunch is from 11-12 pm and dinner is 5-6 pm. Sometimes a movie is shown in the lounge in the evenings, but the other day we streamed the Women’s World Cup to see the USA win their opening game!

Some of the common areas of the ship

view of the survey room. a large island in the center contains cabinets and a map table. computer desks line the walls. four people sit working at computers, while a fifth stands reading something.

The survey room where all the survey technicians have their work stations.

view of the galley, or kitchen, from the service bar on the outside.

The galley with lunch available

tables and chairs in the dining area. the legs of the chairs have been capped with cut open tennis balls to slow sliding during rough conditions.

The mess, where we all eat meals.

three washing machines and two dryers in the laundry room of NOAA Ship Fairweather.

Washers, dryers and soap are provided for everyone’s use.

Did You Know?

Fur Seals leave the Pribilof Islands in November and females and immature males swim to the south, some as far as the California-Mexico border. They return to the Pribilof Islands in June. (https://www.adfg.alaska.gov/index.cfm?adfg=northernfurseal.printerfriendly)
The Pribilof Islands are also home to millions of sea birds. Birdwatchers can see red-faced cormorants, red-legged kittiwakes, northern fulmars, thick-billed murres, and puffins. These species nest in the island’s cliffs and tundra. (https://www.adfg.alaska.gov/index.cfm?adfg=viewinglocations.pribilofislands)

July 15, 2019July 18, 2019

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

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.

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.

NOAA Corps Officer looking at a navigational screen
Instrument panel
thermometers
anemometer
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.

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.

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!

Laundry machines available and detergent is supplied. No need to bring all your clothes. Also, sheets and towels are supplied.

Stairs are called ladders on a ship. Makes sense to me – they’re often pretty steep. You must always hold a rail.

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

August 13, 2018August 16, 2018

Tom Savage: Surveying the Coastline of Point Hope, Alaska, August 12, 2018

NOAA Teacher at Sea

Tom Savage

Aboard NOAA Ship Fairweather

August 6 – 23, 2018

Mission: Arctic Access Hydrographic Survey

Geographic Area of Cruise: Point Hope, northwest Alaska

Date: August 12, 2018

Weather data from the Bridge

Wind speed 8 knots
Visibility: 10 nautical miles
Barometer: 1010.5 mB
Temp: 8.5 C 47 F
Dry bulb 8 Wet bulb 6.5
Cloud Height: 5,000 ft
Type: Alto Stratus
Sea Height 2 feet

Science and Technology

Why is NOAA taking on this challenging task of mapping the ocean floor? As mentioned in an earlier blog, the ocean temperatures worldwide are warming and thus the ice in the polar regions are melting. As the ice melts, it provides mariners with an option to sail north of Canada, avoiding the Panama Canal. The following sequence of maps illustrates a historical perspective of receding ice sheet off the coast of Alaska since August 1857. The red reference point on the map indicates the Point Hope region of Alaska we are mapping.

This data was compiled by NOAA using 10 different sources. For further information as how this data was compiled visit https://oceanservice.noaa.gov/news/mar14/alaska-sea-ice.html.

The light grey indicates 0-30% Open Water – Very Open Drift. The medium grey indicates 30 – 90 % Open drift – Close Pack. The black indicates 90 – 100% very close compact.

Ships that sail this region today rely on their own ships sonar for navigating around nautical hazards and this may not be as reliable especially if the ships sonar is not properly working (it’s also problematic because it only tells you how deep it is at the ship’s current location – a sonar won’t tell you if an uncharted hazard is just in front of the ship). Prior to mapping the ocean floor in any coastal region, it requires a year of planning in identifying the exact corridors to be mapped. Hydrographers plot areas to be mapped using reference polygons overlaid on existing nautical charts. Nautical charts present a wealth of existing information such as ocean depth, measured in fathoms(one fathom is equal to six feet) and other known navigation hazards.

As mariners sail closer to the shorelines, the depth of the ocean becomes increasingly important. Because of this uncertainty in the depth, the Fairweather herself cannot safely navigate safely (or survey) close to shore. In order to capture this data, small boats called “launches” are used. There are a total of four launch boats that are housed on the boat deck of the Fairweather. Each boat can collect data for up to twelve hours with a crew of 2-5. Depending on the complexity of the area, each daily assignment will be adjusted to reasonably reflect what can be accomplished in one day by a single launch. Weather is a huge factor in the team’s ability to safely collect data. Prior to deployment, a mission and safety briefing is presented on the stern of the ship by the Operations Officer. During this time, each boat coxswain generates and reports back to the operations officer their GAR score (safety rating) based on weather, crew skills and mission complexity (GAR stands for Green-Amber-Red … green means low risk, so go ahead, amber means medium risk, proceed with caution; red means high risk, stop what you’re doing). In addition, a mission briefing is discussed outlining the exact area in which data will be collected and identified goals.

Safety Briefing by LT Manda – photo by Tom Savage

Deploying a launch boat – photo by Tom Savage

The sonar equipment that transmits from the launch boats is called EM2040 multi beam sonar. A multi beam sonar is a device that transmits sound waves to determine the depth of the ocean. It is bolted to the hull that runs parallel to the boat, yet emits sound perpendicular to the orientation of the sonar. In the beginning of the season, hydrographers perform a patch test where they measure the offsets from the sonar to the boat’s GPS antenna, as well as calculating any angular misalignments in pitch, roll or yaw. These measurements are then entered in to software that automatically corrects for these offsets.

deploying CTD — TAS Tom Savage deploying the conductivity, temperature and density probe ~ photo by Megan Shapiro

The first measurement to collect is the ocean’s conductivity, temperature and depth. From this information, the scientists can determine the depths in which the density of the water changes. This data is used to calculate and correct for the change in speed of sound in a given water column and thus provide clean data. The boats travel in pre-defined set lines within a defined polygon showing the identified corridor to be collected. Just like mowing a lawn, the boat will travel back and forth traveling along these lines. The pilot of the boat called the Coxswain, uses a computer aided mapping in which they can see these set lines in real time while the boat moves. This is an extremely valuable piece of information while driving the boat especially when the seas are rough.

The coxswain will navigate the boat to the position where data collection will begin inside a defined polygon. Since the multibeam echosounder transmits sound waves to travel through a deep column of water, the area covered by the beam is wide and takes longer to collect. In such stretches of water, the boat is crawling forward to get the desired amount of pings from the bottom needed to produce quality hydrographic data. The reverse is true when the boat is traveling in shallow water. The beam is very narrow, and the boat is able to move at a relatively fast pace. The boat is constantly rolling and pitching as it travels along the area.

As the boat is moving and collecting data, the hydrographer checks the course and quality of the data in real time. The depth and soundings comes back in different colors indicating depth. There is at least four different software programs all talking to one another at the same time. If at any point one component stops working, the boat is stopped and the problem is corrected. The technology driving this collection effort is truly state of the art and it all has to operate correctly, not an easy feat. Every day is different and provides different challenges making this line of work interesting. Troubleshooting problems and the ability to work as a team is crucial for mission success!

Personal Log

I have found the work on the Fairweather to be extremely interesting. The crew onboard has been exceptional in offering their insights and knowledge regarding everything from ship operations to their responsibilities. Today’s blog marks my first week aboard and everyday something new and different is occurring. I look forward in developing new lesson plans and activities for my elementary outreach program. Prior to arriving, I was expecting the weather to be mostly overcast and rainy most of the time. However, this has not been the case. Clear blue skies has prevailed most days; in fact I have seen more sun while on the Fairweather than back home in Hendersonville in the entire month of July! For my earth science students, can you make a hypothesis as to why clear skies has prevailed here? Hint, what are the five lifting mechanisms that generate instability in the atmosphere and which one(s) are dominant in this region of Alaska?

Question of the day. Can you calculate the relative humidity based on the dry and wet bulb readings above? Data table below…… Answer in the next blog

Until next time, happy sailing !

Tom

June 20, 2015August 21, 2021

Sandra Camp: What’s the Most Adorable Fish? June 19, 2015

NOAA Teacher at Sea
Sandra Camp
Aboard NOAA Ship Hi’ialakai
June 14 – 24, 2015

Mission: Main Hawaiian Islands Reef Fish Survey
Geographical area of cruise: Hawaiian Islands, North Pacific Ocean
Date: June 19, 2015

Weather Data: partly cloudy, isolated showers, visibility > 7 NM (nautical miles), winds NE 10-15 KT (knots), seas SE 4-6 ft., air temperature 86° F, water temperature 79° F

Science and Technology Log

So how exactly do marine biologists conduct fish surveys under water? If you are a student in my class, you know that science cannot be conducted all random and willy-nilly. There has to be a standardized procedure in which different variables are controlled in order to ensure the data you collect is meaningful. Some of the variables that are controlled during scientific dives are location, depth, and time.

dive site map — This map shows the survey sites around the island of Hawaii. – photo courtesy of NOAA Fisheries

Location: In order to ensure that scientists get an accurate overview of the health of an island’s reefs, sites from around the entire perimeter of the island are chosen. It would not tell scientists very much if they decided to survey, say, only the eastern side of an island, or only two different sites on the island. As an example, here is a map of the areas that will be visited around the island of Hawaii. On this map, daily survey areas around the island are indicated by red rectangles, as seen on the inset map. The larger map shows each individual dive site in one of those areas. Which area is shown on the large map? Each site is given an identifying number and a code for depth.

Depth: Again, scientists would not get a very accurate picture of the health of the coral reefs if they only conducted dives at the same depth. A variety of diving depths are chosen, and these depths are recorded as shallow, moderate, or deep:

shallow: up to 20 ft

moderate: 21-55 ft

deep: 56-80 ft.

Can you tell me how shallow, moderate, and deep are coded on the map above?

Time: After divers descend to their survey sites, they take a benthic photograph so they can later confirm what type of reef habitat it is. Then they count the fish they see in their location for a certain amount of time. It would not be a “fair” count if one diver counted fish for 10 minutes, while another one counted fish for 20 minutes. For this particular research cruise, pairs of divers (you never dive alone) go under water, stand in one spot, and count the fish they see in a 15 meters diameter cylinder for 30 minutes. The Random Sea Survey graphic here shows how these surveys are conducted. This type of survey is called a Stationary Point Count Survey.

DiverMethod — How a Stationary Point Count Survey is conducted – photo courtesy of NOAA Fisheries

Form Fail — I was on the boat called Metal Shark. Woops!

Every day, each boat completes a Dive and Navigation Information Form. On this form, the boat crew notes the date and number for each site visited. GPS is used to record the latitude and longitude of the site. Ryan, one of the coxswains, taught me how to use the GPS to identify and record latitude and longitude for dive sites. In addition, after the dive is complete, divers complete some information about the site, such as what kind of benthic (floor) cover it has. Here is a picture of a properly completed form, not to be confused with my team’s form, which was a FAIL today (But it was the divers’ section that was not complete, not mine!). Kevin Lino, the scientist being interviewed in today’s blog, completed this excellent example. He is in charge of this whole operation, so his form should be perfect, shouldn’t it?

Dive Nav Sheet — This is an example of the correct way to fill out a Dive & Navigation Form – photo courtesy of NOAA Fisheries

Interview with a Scientist

Kevin Lino is a Marine Ecosystems Research Coordinator for NOAA’s CRED (Coral Research Ecosystem Division), and the Project Leader for this cruise, the Main Hawaiian Islands Reef Fish Survey. He is the man running the show here, and I can vouch that he is very capable and very good at his job.

What are your primary responsibilities? Coordinating operations and logistics for field efforts, primarily conducting reef fish diver surveys. I do pre-planning, documentation, paperwork, certification of divers, surveys, post cruise activities, plus act as dive master and boat instructor.

What do you love most about your job? Fish! I’m a fish nerd, and have been since I was a kid. I was obsessed with sharks as a kid, and loved what Shark Week used to be: real information, not dramatized. Tiko and the Shark was a movie I loved as a kid. I grew up fishing and spending time on boats. Growing up, I had a goal to dive with every species of shark on Earth. I have so far dived with 38. Most of the rest are deep-water sharks, and I would need a submarine to see them.

Do you have a favorite fish? Yes! My favorite fish is the Hawaiian Morwong because it is ADORABLE. My favorite shark is the Mako shark. It is like a miniature Great White shark. It is the fastest shark in the ocean. It has perfect aerodynamics because it is built for speed. It hunts the fastest fish in the ocean: the sailfish.

What kind of education do you need to have this job? I studied biology as an undergrad. I took summer classes in ocean environments and elective courses in marine biology. In college, I also took diving courses.

Do you have any advice for young people interested in your line of work? Study science and math, get in the water, volunteer and help out at places like the Marine Mammal Center, beach/ocean clean ups, and meet other biologists.

Personal Log

Today during small boat operations, our coxswain, Rich (possibly the nicest person I have ever met), let me drive the boat HI-2. There is a lot to maneuvering a boat through swells and protectively around divers. Rich makes it look easy, but it isn’t! I am hoping that before I leave, they will let me try talking on the radio and hook or unhook one of the small boats as they are launched.

Did You Know?

Hawaiian Morwong 2 — Hawaiian Morwong -photo courtesy of NOAA Fisheries

The Hawaiian Morwong, that adorable little fish, has very strong pectoral fins that they use to prop themselves up on the bottom of the sea floor. They eat by pressing their thick, fleshy lips to the bottom, sucking in sand and detritus, and then filtering out small invertebrates.