Tag: Hydrographic survey

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Jennifer Widdig: Charting New Waters, June 26, 2026

View of one of the launch vessels in its berth aboard NOAA Ship Thomas Jefferson. it is very foggy.

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: Friday, June 26, 2026

Weather Data from the Bridge

Latitude: 043o20′ N
Longitude: 077o18′ W
Sky Conditions: Cloudy
Visibility: 9 miles
Wind Speed: 9 knots
Wind Direction: W
Dry Bulb: 18oC
Web Bulb: 18oC

Science and Technology Log

Jen smiles for the camera as she stands at the railing of NOAA Ship Thomas Jefferson, wearing a life vest, her right hand on the metal frame containing the conductivity, temperature, and depth meter (CTD). The apparatus is attached to a line (a rope) that extends out of the photo. the sky and water are bright blue.
Getting ready to deploy the Sea-bird CTD

Surveying has finally begun! Before any data can be collected with the multibeam sonar system, the survey technicians first deploy a Sea-Bird CTD (Conductivity, Temperature, and Depth) instrument. This important piece of equipment measures the water’s conductivity, temperature, and depth throughout the water column.

Why is this necessary? The multibeam sonar determines water depth by sending sound waves to the lake bottom and measuring how long it takes for the echoes to return. However, sound does not travel at the same speed through all water. Changes in temperature, especially at the thermocline where warmer surface water meets colder deeper water, can significantly affect sound velocity. If these variations are not accounted for, the depth measurements could be inaccurate.

two women sit, and a third leans, at a desk with an array of 10 stacked computer monitors.
Survey technicians working at the acquisition station on NOAA Thomas Jefferson

Once the Sea-Bird CTD has been recovered, the survey technicians move to the acquisition station to begin collecting hydrographic data. This is where the real mapping of the lake floor begins.

At the acquisition station, technicians have access to navigation information through HYSWEEP, a software program that displays the planned survey lines and the vessel’s position in real time. Because the survey team and bridge officers are looking at the same information, technicians can communicate precise directions to help keep the vessel on the correct track lines.

The team collects crosslines across each survey sheet. These lines provide an initial overview of the seafloor terrain and later serve as an important quality-control check. By comparing the crossline data to the primary survey lines, technicians can verify the accuracy of their measurements.

Another key display is the Seafloor Information System (SIS), which shows the depth data being collected by the multibeam sonar. As the vessel travels back and forth along carefully planned survey lines, the sonar data appears on the screen like strokes from a paintbrush. Each pass adds another strip of seafloor information until the entire survey sheet has been “painted” with depth measurements.

The survey vessel must travel in straight, parallel lines because the data collected during turns is often unreliable. When the ship turns, turbulence and bubbles form beneath the hull. These bubbles interfere with the sonar signals, preventing them from reaching the bottom and returning accurate depth measurements. On the data display, these disruptions appear as black streaks or gaps, similar to those shown below.

photo of a computer screen displaying color-coded depth measurements in overlapping zig zagging lines
Crosslines on SIS of two sheets complete
photo of a computer screen displaying color-coded depth measurements through a swath approximately the shape of a quarter circle. there are black vertical streaks and a curved line of black dots revealing areas where data was not collected as the ship turned.
Depth data during the ships turn. (Not logged)

During this leg of the mission, the NOAA Ship Thomas Jefferson was finally able to deploy both of its survey launches. This marked the first time this season that both small boats could be used, following repairs to a broken DAVIT cable that had previously limited operations.

Before any launch leaves the ship, the survey team gathers to complete a Float Plan, brief and conduct an Operational Risk Management assessment using a GAR (Green, Amber, Red) score. This process evaluates factors such as weather, crew readiness, equipment status, and mission complexity to determine whether it is safe to proceed.

a group of people, most in navy sweatshirts, stand around a table or sit in chairs in a room inside NOAA Ship Thomas Jefferson
Small boat safety brief
photo of a printed paper sharing the Float Plan for June 24, 2026, SL 2903 / 2904. one section lists Passengers and Crew, another the itinerary, another an Operational Risk Management score sheet. It is initialed at the bottom.
Small boat float plan with GAR score

Once approved, the launches are deployed using the ship’s davit system. The davit lifts the boat over the ship’s rail, and after it is safely positioned, the launch crew boards. The davit then carefully lowers the boat into the water where it begins survey operations.

The survey launches play a critical role in hydrographic mapping. Each boat is equipped with multibeam sonar and side-scan sonar systems that allow surveyors to collect detailed seafloor data in areas too shallow for the ship to safely navigate. By working close to shore and in confined areas, the launches help ensure complete coverage of the survey sheets and provide valuable information for updating nautical charts and identifying potential hazards to navigation.

Deployment of small boat
Recovery of small boat

Because the 2903 launch had not been deployed yet this season, the crew encountered several issues that needed to be addressed during their launch. To tackle these challenges, the Commanding Officer (CO), Executive Officer (XO), engineers, Operations Officers, survey technicians, and available officers gathered for a debrief to discuss solutions and develop a plan moving forward.

One aspect that I found particularly interesting was learning how replacement parts are obtained while the ship is underway. When a needed part is not available onboard, it is often shipped to the nearest port. The crew then evaluates the ship’s schedule, available transportation options, and operational priorities to determine the most efficient way to retrieve it. What might seem like a simple repair on land requires careful coordination and planning at sea.

These debriefs serve another important purpose as well. In addition to troubleshooting equipment issues, they allow the team to review the day’s operations, assess progress, and develop a detailed plan for overnight activities and the following day’s survey work. It was another reminder of the amount of teamwork, communication, and problem-solving required to keep a hydrographic survey mission running successfully.

a group of 8 people, mostly in navy blue NOAA Corps uniforms, stand around a room in discussion
Small boat debrief

Personal Log

It has been really rewarding to take part in more activities on board. I’ve had the opportunity to deploy the Sea-bird CTD and assist with both the launching and recovery of the small boats, which has given me a much better appreciation for how coordinated and precise these operations need to be and how many hands are needed. Thank you to Chief Scientist Sarah Thompson and Bosun Alex Bischoff for the opportunities to help out along side them. I’ve also really enjoyed observing the work on the bridge and seeing how navigation, communication, and decision-making all come together in real time to keep operations running safely and efficiently.

One of the biggest adjustments for me has definitely been the 4:30 p.m. dinner time! Eating three full meals between the hours of 7am and 4:30pm is slowly killing me, but it is SO hard to skip a meal when everything is so good. I’ve also been surprised by how cool the temperatures have been while on board which has been really nice. I have spent most of the time in pants and light sweaters.

My photo was also added to the crew board, which made me feel even more like part of the team and included in the daily life of the ship. Overall, being exposed to so many different roles and responsibilities on board has been eye-opening. If I had known earlier about the range of careers involved in hydrography and ship operations, I absolutely would have considered this path when I was younger.

a group of 5 polaroid photos pinned to a cork bulletin board under a small title, separately pinned, that reads "Augmenters." Each photo is hand-labeled. The first is a photo of Jen sitting at a computer, labeled "TAS Widdig." The other augmenting crew are identified as ENS Ruiz, ENS [illegible], 2C Grant, CC Wright.
Newbies photos on the board on NOAA Ship Thomas Jefferson

Did You Know?

Ports are not required to maintain current depth information for their slips, which can increase the risk of vessels running aground. Can you see the dock in the background we are backing in to in Osewgo?

View down the starboard side of NOAA Ship Thomas Jefferson from an upper deck; we can see one of the launch vessels in its berth. it is very foggy and we can barely make out the horizon.
NOAA Ship Thomas Jefferson backing into Port of Oswego

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Jennifer Widdig: Drills before Thrills, June 22, 2026

NOAA Teacher at Sea

Jennifer Widdig

NOAA Ship Thomas Jefferson

June 17 – June 30, 2026

Mission: Hydrographic Survey
Geographic Area of Cruise: Lake Erie and Lake Ontario
Date: June 22, 2026

Weather Data from the Bridge

Latitude: 043o 27’N
Longitude: 076o30’W
Sky Conditions: Foggy
Visibility: < 1 miles
Wind Speed: 8 knots
Wind Direction: E
Dry Bulb: 14oC
Wet Bulb: 16oC

Science and Technology Log

Since my last blog, Junior Officer James Hutzenbiler has been qualified, meaning that all permanent officers on the ship now have their Officer of the Deck Underway Letter (Underway OOD).

Practice Makes Prepared

Grinning big for a photo, Jen holds up an orange personal flotation device in one hand and grasps the handle of a bagged survival suit in the other hand
Ready for abandon ship

Life aboard the NOAA Ship Thomas Jefferson is filled with exciting scientific work, but safety is always the top priority. Whether the crew is conducting hydrographic surveys, navigating busy waterways, or working far from shore, everyone on board must be prepared to respond quickly and effectively in an emergency. That preparation comes through regular safety drills and a strong culture of readiness.

Every week, the crew participates in both fire drills and abandon ship drills. In addition, man overboard drills are conducted monthly to ensure everyone remains familiar with emergency procedures. Leading these exercises is Megan McDeavitt, the Damage Control Officer (DCO), who is responsible for planning, coordinating, and evaluating each drill. To keep the crew prepared for real emergencies, the DCO often creates surprise scenarios. During the first fire drill I experienced, simulated smoke was released in a particular area of the ship. Crew members had to adjust their movements and follow alternate routes. These realistic situations challenge the crew to think critically and adapt to changing conditions.

One of the first safety items introduced during orientation is the Emergency Escape Breathing Device (EEBD). An EEBD is located in every room throughout the ship and provides a supply of breathable air that allows individuals to escape from smoke-filled or hazardous environments. 

the emergency escape breathing device, housed in round plastic casing, in front of a bright orange plastic box that reads EEBD; both rest on a table.
Emergency Escape Breathing Device

When joining the ship, every crew member receives a billet card that outlines their responsibilities during each type of drill. The sheet identifies primary and secondary muster locations, ensuring everyone knows exactly where to report. The secondary muster station is especially important because emergencies can sometimes block access to the primary location.

close-up view of a small piece of paper attached by magnet to the door. at the top it reads: 2026-06-18 to 2026-06-23, TJ-26-02, Welland and ROV, TAS Widdig, Jennifer. Muster instructions are listed below for different scenarios, color coded. Red: Fire & Emergency, Yellow: Abandon Ship, Blue: Marine Overboard. White boxes of different sizes against the colored bars indicate the sound of the emergency signal. Fire & Emergency is one long bar; Abandon Ship is 8 small boxes plus a medium sized box; Marine Overboard is 3 medium boxes.
Billet Card

During a fire drill, the crew reports to their assigned muster stations where attendance is carefully checked. Once a complete muster is attempted, attention turns to any missing personnel. This is where the ship’s medical personnel in charge (MPIC) becomes involved. If a scenario includes an injured or unaccounted-for crew member, responders must locate, assess, and assist that individual while the fire teams continue addressing the simulated emergency.

The Thomas Jefferson maintains three separate fire teams, each trained to respond rapidly to emergencies. Team members must quickly don their firefighting gear, deploy equipment, and establish water to the simulated fire. Working together, the teams communicate their progress while searching affected spaces and ensuring the safety of all personnel.

emergency equipment on board the ship: a bright red metal locker, red hard hat, red fire extinguisher. also some sort of breathing apparatus and balled up fire protection gear.
Fire team station on NOAA Ship Thomas Jefferson

Abandon ship drills require a different type of preparation. When the abandon ship alarm sounds, crew members must report to their assigned muster station with their life jacket and their immersion suit, often referred to as a “Gumby suit.”

Following every exercise, the DCO conducts a detailed debrief with the crew. During this review, performance metrics are discussed, including how long it took to complete the muster, how quickly each fire team arrived on scene, how fast firefighters dressed in full protective gear, when water was established to fight the fire, and how efficiently missing or injured personnel were located. The crew also examines any challenges encountered during the drill and discusses ways to improve future responses.

Charting a Course for Discovery

Before each leg of operations, there is a briefing. Operations Officer Mark Meadows outlined the goals for the NOAA Ship Thomas Jefferson’s work on Lake Ontario. The mission is to update nautical charts, identify dangers to navigation, and replace outdated survey data collected in the 1940s.

screenshot from a NOAA webpage titled LAKE ONTARIO. the page features a a satellite map of the lake with red tracklines inside black polygons overlaid on the water. Text superimposed at the top of the map reads: "Existing Data Quality: 1940's, Fathometer, Set Line Spacing @1.5 nm, USACE 2018 nearshore Lidar Data."
The red lines mark the original survey lines from the 1940s.

Many of the original survey lines on Lake Ontario were spaced approximately 1.5 miles apart. While this was considered sufficient at the time, it left vast areas of the lake bottom completely unsurveyed. Modern hydrographic technology allows NOAA to collect much more detailed information, creating safer and more accurate nautical charts for everyone who uses these waters.

The survey efforts also support the Lake Ontario National Marine Sanctuary and the Lakebed 2030 project, an effort to map the entire lake floors by the year 2030. To maximize coverage, the Thomas Jefferson operates nearly around the clock, collecting shipboard data 24 hours a day. During daylight hours, two smaller survey launches focus on nearshore and shallow-water areas that the ship cannot safely access.

The survey team enjoys a little fun when naming the survey sheets. OPS Meadows felt the need to name the nearshore sheets various flavors and heat levels from Dave’s Hot Chicken. Additionally, they decided to divide the midshore sheet into Bert and Ernie. While the names may not appear on the official charts, it added a little humor to the serious business of mapping Lake Ontario.

simple map of the south shore of Lake Ontario, with 5 polygons drawn against the shore in a line. each polygon is shaded a different color and named: mild, medium, hot, extra hot, reaper.
The Dave’s Hot Chicken Survey Sheets.

Personal Log

A Taste of Life on Board

One of the biggest surprises of my Teacher at Sea experience has been the incredible food. Every meal seems to bring something new, and the variety has been nothing short of amazing. In just a short time on board, I have enjoyed rabbit, lamb, gyros, steak, salmon, and even a delicious crawfish boil. Additionally, the desserts are to die for! The rice pudding being my favorite so far. Each meal is thoughtfully prepared, and there is always something to look forward to when the dinner bell rings.

One evening, Chief Steward (CS) Danni Cuff created a stunning croquembouche, which is a towering French dessert made of cream-filled pastry puffs held together with caramelized sugar. It looked like something that belonged in a bakery window rather than on a hydrographic survey vessel in the middle of the Great Lakes. More importantly, it tasted every bit as good as it looked!

a towering dessert more than a foot tall of ping-pong sized balls of pastry arranged in a christmas tree shape
CS Cuff’s Croquembouche

The crew aboard Thomas Jefferson also takes condiments very seriously. I am convinced there is every type of condiment imaginable somewhere in the galley. Ketchup, mustard, hot sauces, barbecue sauces, dressings, seasonings. You name it, they probably have it. And not just one version, but multiple brands and varieties. Whatever your taste preference may be, there is likely a condiment waiting to make your meal even better.

two tables in the mess hall, each lined with plastic boxes containing a wide variety of condiments
The stash of only the table condiments.

The galley always offers a small salad bar stocked with fresh vegetables and toppings. Fresh fruit is also available throughout the day, making it easy to grab a healthy snack between surveys, drills, and shipboard activities. Then there are also tons of unhealthy snack options available as well.

As a Teacher at Sea, sharing meals with crew members from every department makes it easy to get to know people and learn about their unique roles on the ship.

Did You Know?

There are an estimated 4,000-6,000 shipwrecks on the Great Lakes.

two divers check out an underwater shipwreck in green waters
The wreck of the St. Peter in Lake Ontario (Credit: NOAA)

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Elli Simonen:  The Survey Team, July 27, 2023

NOAA Teacher at Sea

Elli Simonen (she/her)

Aboard NOAA Ship Fairweather

July 10-28, 2023

Mission:  Hydrographic Survey of the Pribilof Islands 

Geographic Area of Cruise: Pribilof Islands, Alaska

Date: July 27, 2023


Weather Data

Location: 55°54.11’N, 168°33.69W

Outside temperature: 11°C

Water temperature: 10.5°C

True Winds: 8nm, 211.9°

Skies: Overcast and Foggy

Visibility: 5nm

Sea Wave: 1 ft

Swell Wave: 2 ft

Science and Technology Log

The entire survey department has diverse backgrounds rooted in Science and each took different paths before coming to NOAA Ship Fairweather.  Their studies in college include Geography, Quantitative Geoscience, Environmental Science, Economic Environmental Policy, Space Studies, Physical Oceanology, Applied Math, Computer Science and Marine Biology.  

I wanted to highlight two people in the survey department who I worked with over the last 3 weeks.

Alex Dawson, Physical Scientist, Project Manager for the Pribilof Islands

Alex studied in one of the only hydrographic programs in the U.S. for undergraduates, at the College of Charleston.  This is a unique program where students gain technical, practical and research knowledge and experience.  Alex obtained bathymetric data and translated this into a research project.  She presented this information at a professional conference, which put her ahead of many of her peers.

In her current job at NOAA headquarters in Silver Spring, Maryland, Alex is a Physical Scientist and a Project Manager.  She plans projects for the entire U.S. Exclusive Economic Zone (EEZ) and planned this Hydrographic Survey of the Pribilof Islands; she is aboard NOAA Ship Fairweather for their Pribilof Island Surveys .   Each project takes about 2 to 6 months to plan depending on the complexity of the specific area being surveyed.  Alex and her team do this by looking at the environment of the area, known features and existing charts. She develops environmental compliance best management practices so the survey does not impact the local ecosystem or marine life.  Any features that are on existing charts such as obstructions, shipwrecks, rocks, or pipelines will be included in the project’s GIS files, and she determines if those features need to be investigated more thoroughly. This is all put together in a project package that is sent to the hydrographic ship– the footprint of the survey, any special features that need to be investigated, environmental compliance information, and any previous surveys in the last 20 years that may abut or overlap the planned survey area.  Alex also does hurricane response work; if a hurricane hits a port, then the port will be closed until a federal hydrographic survey comes in to make sure it is safe for commerce.  This is done as fast as possible, sometimes within 24 hours.

Which projects get fulfilled depends on the navigational risks of each area.  Alex explains: “Coast Survey determines which areas to survey within U.S. ports, harbors, and approaches, as well as U.S. waters more broadly, by using the risk-based Hydrographic Health Model. The model assesses risks to surface navigation from charted bathymetry and features, including both the likelihood of a risk (e.g. traffic density, known hazards to navigation, reported ship groundings, etc.) and the consequence of a risk (e.g. proximity to search and rescue stations, proximity  to public beaches, reefs, or marine sanctuaries, etc.). A resulting accuracy factor indicates the urgency (or lack thereof) for new hydrographic surveys.”

In Alex’s own words:
“I love mapping in general, but I think it’s really cool to map in an area such as the Pribilofs… to uncover what hasn’t been uncovered before – mapping where no one has mapped before.”

photo of a young woman standing on deck in front of a view of a teal-colored ocean and hilly green islands in the distance; the sky is blue with some low white clouds. Alex wears a navy blue sweatshirt with a NOAA logo and a silhouette of NOAA Ship Fairweather (with the numbers S-220) imposed on top of the logo. Her hair blows in the wind.
Alex Dawson aboard NOAA Ship Fairweather en route to the Pribilof Islands

Sara Ober, Hydrographic Survey Technician

Sara got her B.S. in Marine Biology from Texas A & M University.  After college, she worked for 5 years in Alaska as a fisheries observer contracted through NOAA through the North Pacific Observer Program.  She worked on smaller fishing boats to observe what they were catching and when.  The calendar of the fishing seasons and quotas in Alaskan waters are mostly federally managed and she would observe the catch at the beginning, close and during the season and pass on that data to the Alaska Fisheries Science Center in Seattle. 

Sara then became a survey technician with NOAA.  At the time, hydrography was new to Sara, but she is currently in her second year and likes training newer survey technicians on how to precisely look at the data and check for accuracy.  Every morning she makes sure everything is ready for the plan of the day in terms of surveying, ensures the processing from the night before is ready and addresses anything if needed.  She likes helping others learn and members of the survey team often go to her for advice.  

In the future, Sara is hoping to combine her marine biology and hydrography experiences together and do benthic habitat map work.  The benthic zone is the ecological region found at the bottom of a body of water.  Sara would like to use sonar data to see what the seafloor looks like and why fish live there, as well as predict where they migrate to. 

In Sara’s own words: 

“I really like hydrography, the technical part is fun and new to me.  I wasn’t expecting to like it as much as I do. Being able to visually see something is very cool to me and having such an impact on things.  We can see our direct impact when we submit our data and later on when nautical charts get updated.  It’s like, this is what I did and here’s the final product. 

I love being in Alaska.  I like working on a ship, I think it’s fun.”

a young woman in a gray sweatshirt sits at a computer and smiles for the camera
Sara Ober working in the Survey Department aboard NOAA Ship Fairweather

Personal Log

We will be arriving at port tomorrow in Dutch Harbor and my time on NOAA Ship Fairweather is coming to a close.  I want to thank the entire crew for showing and explaining to me the amazing work they do and making me feel at home.  The crew is highly skilled, patient, respectful and willing to pretty much do anything to help the mission.  Their commitment to Science, to NOAA and to each other is commendable. 

I especially want to thank LT Taylor Krabiel and Commanding Officer CMD Meghan McGovern for their hospitality, guidance, continuous check-ins, and making the most of my time.

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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.

headshot of Elli on a survey launch vessel. she's wearing a heavy jacket and a Teacher at Sea beanie. we can see St George's island in the background.

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?

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Elli Simonen: Geology, Engineering and Mapping, July 19, 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 19, 2023
Weather DataLocation: 57°11.82’N, 170°27.52’W

Outside temperature: 13°C

Water temperature: 11°C

True Winds: Direction 242.4°, 13.7 kn

Skies: Overcast and Foggy

Visibility: 2 nm

Sea Wave: 2 ft

Swell Wave:  Direction 240°, 4 feet height

Science and Technology Log

We have arrived at the Pribilof Islands after being en route from Kodiak for 3 days.  We are currently surveying.

Geology of the Aleutian Islands

The Aleutian islands stretch from North America into the Pacific and contain 40 active volcanoes.  This string of islands is where the Pacific Plate sinks under the North American Plate causing some of the largest earthquakes of the last 100 years.  NOAA Ship Fairweather often receives alerts about Volcanic Eruptions including information about ash in the water when sailing around the Aleutian Islands.


On July 15th at 10:48 pm, at a depth of 13 miles, a 7.2 magnitude earthquake struck just south of the Aleutian Peninsula, triggering a tsunami watch and then warning.  NOAA Ship Fairweather was in the direct vicinity, but did not feel a noticeable shake. Luckily the tsunami watch and warning were canceled shortly after, and the earthquake did not cause significant wave heights.  Investigation of observed water levels at the Sand Point, AK tide station showed some variability when compared to the tide predictions.

a photo of a graph displayed on a computer screen. The graph is titled NOAA/NOS/CO-OPS Observed Water Levels at 9459450, Sand Point AK from 2023/07/15 12:00 LST_LDT to 2023/07/16 23:59 LST_LDT. We can see that the x-axis displays time - starting at 18:00 hours on July 15, with grid marks every 3 hours until 09:00 hours on July 16. the y-axis is out of view. A dotted blue line labeled "predictions" rises smoothly to a high point around 01:30 on July 16, and then dips again. A solid red line, labeled "water levels," mostly tracks the "predictions" line but is visibly wobbly around midnight on on July 16.

Observed water levels the night of the earthquake and tsunami warning.

Video showing the Bow of NOAA Ship Fairweather sailing just south of the Aleutian Peninsula

Engineering On Board

The engineering team on NOAA Ship Fairweather consists of 8 engineers.  They are in charge of maintaining the engine, all power and water on board.  They typically work in 4-8 hour shifts, 24-hours per day, to ensure everything is running smoothly.  The ship’s two main engines power shafts that are connected to controllable pitch propellers.  To move a boat forward, both the pitch of the propellers and Revolutions Per Minute (RPM) are adjusted.  Pitch is the angle of the propeller blades and RPM is how many times the propellers rotate per minute. 

The engine room also supplies clean potable water for the entire ship.  Through the process of reverse osmosis, sea water is compressed in cylinders and salt is filtered out.  The water then goes through multi-stage and UV filters to ensure safe sanitation. 

Power is supplied by three generators and one emergency generator.  These generators power all electric, navigational and satellite receiver systems.

an engine in the engine room

One of the Engines

a tank, pipes of different sizes, a control panel

Reverse Osmosis Unit, used to make potable water from seawater

Elli, wearing her Teacher at Sea hat, stands in front of a large floor-to-ceiling control panel. Behind her there is a closed door with a yellow sign cautioning people to wear ear protection beyond that point.

TAS Elli Simonen in the Engine Room

Surveying with NOAA Ship Fairweather

We have been surveying at the Pribilof Islands for the last 1-2 days.  We are surveying using the ship and the team is on a 24 hour rotation.  The survey area is divided up into polygons, or smaller areas, of which we completely cover one at a time.  The ship drives back and forth in overlapping lines over the designated polygon.  In addition to the MBES data, we gather both backscatter and water column data as well.

Backscatter is a visual representation of the surface of the seafloor.  Backscatter provides information about the intensity of the returned echos, from which the “hardness” of the bottom as well as other characteristics can be used to differentiate between different types of seafloor composition.  Darker colors represent harder surfaces such as rocks and hard coral and lighter colors represent softer surfaces such as sand and mud.  This information is important for ships to know for anchoring purposes, as well as benthic habitat characteristics.

The water column data shows us what is under the ship throughout the water column– from the surface of the water to the seafloor.  It detects bubbles, objects protruding from the seafloor, fish, or even a whale or a seal.

a triangular swath of echosounder data in different colors (red, green, blue) indicating the intensity of the returned echoes

Water column Data

photo of a computer screen displaying seafloor bathymetry (in black and white) from backscatter

Backscatter showing a representation of the seafloor

Finnegan and Elli sit in desk chairs in front of an array of computer monitors. There's a bookshelf filled with binders, an electrical box mounted to the wall, papers clipped to another wall. Finnegan and Elli are both wearing navy-colored NOAA logo-ed apparel.

TAS Elli Simonen with Survey Technician Finnegan Sougioultzoglou

Personal Log

Safety and Routine Checks

Before coming on board, I did not realize all the preemptive safety measures that need to be taken to ensure the health and safety of everyone on board.  The staff and crew need to be self-sustaining on all accounts; another person, equipment or supplies cannot be added mid-sail.  There are cooks onboard as well as medical staff.  There are 3 drills and situations that the entire crew participates in, including myself – Fire, Mariner Overboard and Abandon Ship.  You need to know the pattern of alarms for each, as well as where to go and what to do.  For example, for Mariner Overboard I go to the fantail of the ship, with others, and point at the person in the water until a small boat can go out and rescue them.  Each one of these drills is practiced periodically. Additionally there are two sets of rounds every hour, 24 hours a day – a deck round and engine rounds.  Deck rounds check all public spaces for anything abnormal.  Engine rounds check the engine room to see if everything is working properly.  Every week, refrigerators are checked for correct temperatures and water is checked for potential bacteria.

New Terms/Phrases

I’ve learned several acronyms and initials since I have been on board NOAA Ship Fairweather.  Sometimes I feel two consecutive sentences cannot be said without some type of abbreviation.  These are some that have become part of my vocabulary: 

  • HIC: Hydrographer in Charge
  • POD: Plan of the Day
  • SOP: Standard Operating Procedure
  • NM: Nautical Miles
  • CO: Commanding Officer