Denise Harrington: If Hydro Means Water and Graphy Means Writing, What Is Hydrography? April 22, 2014

NOAA Teacher at Sea
Denise Harrington
Aboard NOAA Ship Rainier
April 21 – May 2, 2014


Project: North Coast of Kodiak Island

Weather Data from the Bridge at 15:20

Wind: 11 knots

Visibility: 10+ nautical miles

Weather: Clear

Depth in fathoms: 66.1

Temperature: 9.8˚ Celsius

Latitude: N 48˚13.15 Longitude: W 123˚21.04

Science and Technology Log

My first log will be mostly about setting sail and the breadth of skills which each crew member is required to possess when working in hydrography, which is the science of surveying and charting bodies of water or seafloor mapping.  Later, I hope to zoom in on the crew, scientists, and tools they use. Meetings….a time to get together with co-workers and catch up, and get a little work done. Not at NOAA: at 8:00 a.m. on April 21, Lieutenant Commander Holly Jablonski, Executive Officer called a meeting to let junior officers know the ship would be sailing at 12 p.m. Originally scheduled to depart on March 28, Rainier could not leave unless positions of highly qualified crew were filled, and difficult to replace parts were found and installed. Potentially hazardous ocean conditions would have delayed the departure another day so Officers were pleased the ship would depart. Members of the Junior Officer team proceeded to list off work they must complete to have the ship ready to sail in the next two hours, equipment to deliver, test and secure, and inspections to complete. Not a word was wasted. Within five minutes the meeting ended and each officer quickly returned to their many collateral duties. Ensign Katrina Poremba gave me a tour of the ship as we updated emergency billets, critical information that informs crew of their responsibilities during drills and actual emergencies. Before long, we were underway. Families of crew members wished them farewell, fair winds and following seas. As the ship pulled away, I entered the bridge, where Commander Rick Brennan, the Commanding Officer, and others were sailing the ship out of Newport Bay.

NOAA families see their loved ones off wishing them fair winds and following seas.
NOAA families see their loved ones off wishing them fair winds and following seas.

On the bridge, officers eyed a crabbing boat in “The Jaws,” the jetties at the entrance to Yaquina Bay, and mentioned that it did not appear to be making progress. With twelve foot swells, at 13 second intervals, the bar is a bit rough and it seems to me to be a risky place for a boat to turn around, but this is what the crabber did. Maybe it was too rough for them today, but now we had to pass them in a narrow passage with shifting depths. Lieutenant Junior Grade Bart Buesseler mentioned that Rainier’s hull is 16 feet deep and that a 2.5 million dollar piece of multi-beam sonar equipment sits at its lowest point of the hull. This is some of the best mapping equipment in the world. On the bridge, about seven officers and helmsmen maneuvered the ship around the crab boat in the narrow passage. An alarm sounded, signaling a low depth warning. I wondered about the wisdom of placing such expensive equipment in such a vulnerable position. Later I learned that the sonar equipment is protected by a steel shell called a gondola, but also that the equipment must be placed at this deepest location of the hull to maximize smooth sonar transmission and reception.  Like the sonar equipment, I feel protected in the capable hands of Rainier crew. As each alarm sounded, several of the six officers moved to a variety of locations on the bridge to collect data about all variables, water depth, the distance to the crab boat, angle and speed of travel, swell and breaking waves. The crabber passed us uneventfully, and within seconds, we had breaking 12 foot waves on both sides. Avoiding hazards as we passed safely though the bar reminded me why accurate nautical charts, based upon reliable data, are necessary tools for all vessels. Gathering the data to create accurate charts is Rainier’s project this season.

Commanding Officer Rick Brennan, Executive Officer Holly Jablonski, Junior Officer Micki Ream and Junior Officer Bill Carrier are all part of the team that gets us safely across the bar.
Commanding Officer Rick Brennan, Executive Officer Holly Jablonski, Junior Officer Micki Ream and Junior Officer Bill Carrier are all part of the team that gets us safely across the bar.
Multibeam Sonar System
Multibeam Sonar System

After navigating us through the bar, several officers left and Starla Robinson, a senior survey technician joined us on the bridge to make sure we were collecting new information about the ocean depth as we travel north.

Surveying Computer Program
Surveying Computer Program

Rainier has a Multibeam Sonar System and a Rolls-Royce Moving Vessel Profiler (MVP) 200 sound speed acquisition system used to collect large amounts of data and make high resolution maps of the ocean floor. The sonar equipment gathered information represented on two screens on the bridge and multiple screens in the plot room, sending down pings through the water that bounce back up.  Based upon the time it takes for the sound to return to the ship, the equipment measures the ocean depth. As a senior survey technician, it is Starla’s duty to coordinate between Field Operations Officer Quintero, “FOO,” and the crew on the bridge to follow a track line measuring ocean depth. She invited me into the plot room where many large computer screens display rainbow colored images of the ocean floor. There were divots in the rainbow image which Starla explains could be thermal vents, and blue dots, which could be schools of fish. Another unexplained change in the ocean floor caught her attention.  She market that spot on the chart with a caption, “look later.” She said with a smile it might be a shipwreck that she planned on checking out that evening.

As we travel north on the map, the yellow swaths indicate areas already surveyed. Rainier’s current survey data is represented in black. This surveying is much like mowing the lawn, you want to travel in a track that matches the edge of a previous route and does not overlap significantly. All surveyors and officers spent time focusing on the collection of this data until the afternoon of our second day of travel, when we entered the Strait of Juan de Fuca, where the route is heavily traveled and well surveyed making additional data collection unnecessary.

Teacher at Helm Watch Out Crab Pots!
Teacher at Helm
Watch Out Crab Pots!–Photo by Anthony Wright!

In the past, ocean depth was measured with a lead line dropped into the water until it hit bottom.

Image courtesy of NOAA at
Image courtesy of NOAA at

Now, scientists use sonar or sound pings reflecting off the ocean floor, to measure depth much more efficiently. Several years ago, the Rainier crew surveyed an area of the Columbia River Bar in 1 ½ months might have taken 50 years worth of work under the old, lead line methodology. In addition, with the sonar method, scientists see the ocean floor in much greater detail, which no longer appears like dots, but instead comes back in a three dimensional image.

In this photo, the area without highlighting (red) shows how much surveying one boat does off the small boat in shallow water.  The shallower the water, the more time consuming the survey becomes.
In this image, the area without tracking marks appears bright red and shows how much surveying one boat completes in shallow water. The shallower the water, the more time consuming the survey becomes.

The track line survey on our route north is ancillary to the crew’s primary mission: to collect hydrographic data around Kodiak Island. This map shows where the crew will work this year, collecting depth measurements and reviewing data for accuracy.

Sheet Assignments for  2014 Season
Sheet Assignments for 2014 Season

I will be telling you more about sheet assignments and the review process later. Then survey technicians and officers file a report which becomes part of a new nautical chart, including areas identified as dangers to navigation.

Every conversation on board seems to include math and science. Johnny Brewer, a junior engineer who helps keep the ship moving forward, spoke of the need for everyone on board to have a good understanding of Algebra and Trigonometry, for anything from mixing paint to ship stability. A half hour later, on the bridge, the officers are discussing trigonometric formulas relevant to the length of anchor line. Many crew spoke of the training, testing and sea days NOAA provides so that crew members continue to develop a broad range of skills and move forward in their careers whether they are Stewards, Engineers, Survey Technicians or Officers. It is clear that math, science, technology and cross training for everyone play an important role in the daily lives of this NOAA crew.


Personal Log

My son Martin delivering me to Rainier just in time for a beautiful sunset.
My son Martin delivering me to Rainier just in time for a beautiful sunset. Photo by Jeff Mays
Reconnaissance by Kayak.  Photo by Joseph Jones
Reconnaissance by Kayak.  Photo by Joseph Jones

Several crew spoke of the transit as an opportunity for some down time. Yet seeing how the crew multitasks constantly, all day and night, I wonder what the day will look like when we begin our hydro work in Alaska. Okay, maybe there is a little down time: here is a shot of me, Engineer Patrick Price and Starla Robinson, surveying by kayak the nooks and crannies of Canoe Island in the San Juan Islands. DID YOU KNOW? Newer ships hold effluent but because Rainier is a relatively older ship, it has a marine sanitation device (MSD) that separates sodium and chloride, making a chlorine solution from our waste, and sanitizing the effluent for discharge. To learn more about what happens in the MSD, here is a fun chemistry experiment you can try: .

Second grade hot science topic: in the sight glass, orange is detergent, white is emulsion and brown is ...gross.
Second grade hot science topic: in the sight glass orange is detergent, white is emulsion and brown is …gross.

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