seafloor mapping – Page 9 – NOAA Teacher at Sea Blog

July 14, 2009April 5, 2021

Stacey Klimkosky, July 14, 2009

NOAA Teacher at Sea
Stacey Klimkosky
Onboard NOAA Ship Rainier
July 7 – 24, 2009

Mission: Hydrographic survey
Geographical area of cruise: Pavlov Islands, Alaska
Date: July 14, 2009

Weather from the Bridge
Position: 55°11.664’N, 161°40.543’W (anchored off SW Ukolnoi Island)
Weather: OVC (overcast)
Visibility: 10 nm
Wind: 28 kts.
North Seas: 2-3’
Sea temperature: 7.8°C
Barometric pressure: 1021.0 mb and rising
Air temperature: Dry bulb=12.8°C; Wet bulb=10.0°C

This is a survey launch lowered to deck level on a calm day. The bow and stern are attached to the davits by thick line. Notice how you have to step across the space between Rainier and the launch.

Science and Technology Log

The past few days have been “typical” Alaska weather—fog, drizzle, moderate winds. This morning I was quite surprised when I looked out my stateroom porthole. The weather was supposed to have calmed somewhat overnight; however, it was obvious that a good blow had picked up. White caps covered the water’s surface. I was scheduled for a launch, RA-4 (each of the launches has a number 1-6, RA being the abbreviation for Rainier), but I decided not to board at the last moment. When the launches are lowered to the side of the ship, the bow and stern (front and back) are secured with line to minimize movement. To board the launch, you have to step across a 1-2 foot gap from Rainier to the launch. Today’s conditions amplified the heaving and pitching motion of both the ship and launch and made the distance between too far for my short legs. I chose safety over adventure today.

As the launches continued to be deployed, Rainier began to transit from our anchorage north of Wosnesenski Island to our previous anchorage position in a small cove off the southwest corner of Ukolnoi Island. Having the flexibility to change the ship’s direction was essential for the safe deployment of launches today. Personnel and equipment could be protected from the force of the wind and waves (which topped 6’ at times). Although disappointed that I did not make it onto my launch, I was given an opportunity to watch the deck crew in action. I learned that this morning’s weather was some of the worst that the crew has seen during this survey season, however, work can be completed in conditions that are more blustery than today.

As a member of a survey team, you have to put your trust in the deck crew and their talents and skills. Jimmy Kruger is the Chief Boatswain. He is in charge of the deck and its crew. In a way, he is like the conductor of an orchestra—he makes sure that each member of the crew is in the right place at the right time and that they begin their job at precisely the right moment. As the day progressed, I began to wonder how the weather data from 0700 to 1400 (2 pm) changed, so I took a walk up to the bridge. My guess was that, although there were still whitecaps on the surface, wind speed and wave height would have decreased, since we had anchored on the south shore of one of the islands (which would serve as a buffer from the wind). It seemed to me that the weather was so much worse this morning. Not so. The wind speed had actually increased by a few knots, although the seas had decreased by about a foot. When I am up on the bridge, I always find something new to inquire about. It’s a busy place—not necessarily busy with numbers of people, but with instruments, charts and readings. General Vessel Assistant Mark Knighton and ENS Jon Andvick were on the bridge.

We sought a better anchorage southwest of Ukolnoi Is. when a 30 knot wind picked up. White caps cover the surface, the flag blows straight out facing aft.

When you are standing on the bridge with a gusty wind coming at you, you immediately think of the anchors. Rainier’s anchors are made of steel. They weigh 3,500 lbs. EACH! The anchors are attached to the ship by a very thick chain. Chains are measured in a unit called a shot. A shot equals 90 feet, and each of Rainier’s shots weighs about 1,100 lbs. There are 12 shots per anchor. (So, can you calculate the approximate weight of the total of Rainier’s shot? How about the total length of the chain?) The depth of this small cove is between 9-10 fathoms. This is important in determining the scope, or ratio of the chain length to the depth of the water. According to ENS Andvick, when a vessel drops anchor, the length of the shot cannot be the exact distance between the vessel and the seafloor. An amount of “extra” chain must be released so that some of it sits on the seafloor, producing a gentle curve up to the vessel. This curve is called a catenary. The extra chain allows the ship move with the wind and/or waves and provides additional holding power. If either wind or current becomes too strong for the anchor, it will drag along the seafloor. If the ship has too little scope it will pull up on the anchor instead of pulling sideways along the sea floor. The anchor chain lies on the bottom and when the ship pulls on the anchor it must lift the heavy chain off the bottom. If there is enough chain that the ship does not lift all the chain off the sea floor, it will lower the effective pull angle on the anchor. By increasing the scope of chain that is out, the crew is increasing the amount of weight the ship must lift off the sea floor before pulling up on the anchor.

Personal Log

I have to say that today was kind of an emotional one for me—because I did not go out on the launch. In a way, I feel like I let my team down. The others who went surveying on RA-4 had to do it without me. Even though my work as a Teacher at Sea may not be as significant as that of the crew members or hydrographers, I’m feeling like I am a part of the team more and more each day. That is in contrast to being an observer (which I still do plenty of!). As I kept busy throughout the day on the ship, I thought about RA-4 and what they were doing, what the conditions were like, if they liked what was in the lunch cooler today? I also realize and appreciate, however, that safety is the most important practice here on Rainier and when you don’t feel safe, you should never proceed.

Did You Know?
The crew on Rainier is organized into six separate departments: Wardroom (Officers), Deck, Electronics, Engineering, Steward and Survey. There are photographs of each person on board along with their name and title posted for all to see. They are organized by department as well as a “Visitors” section. There are several other visitors on board besides me and Dan Steelquist (the other Teacher at Sea) including hydrography students and officers from the Colombian and Chilean Navies.

Alaska Fun Facts

Pavlof Volcano is one of the most active of Alaska’s volcanoes, having had more than 40 reported eruptions since 1790. Its most recent activity was in August 2007.
You can learn more about the volcanoes of the Alaska Peninsula here.

July 10, 2009April 5, 2021

Stacey Klimkosky, July 10, 2009

NOAA Teacher at Sea
Stacey Klimkosky
Onboard NOAA Ship Rainier
July 7 – 24, 2009

Mission: Hydrographic survey
Geographical area of cruise: Wosnesenski & Ukolnoi Islands, Alaska
Date: July 10, 2009

Weather from the Bridge
Position: 55°11.715’N, 161°40.554’W
Weather: Foggy
Visibility: < 0.5 nautical miles
Wind speed: 7knts
Swells: 0-1 ft.
Waves: 0-1 ft.
Barometric pressure: 1022.8 mb
Air temperature: Wet bulb = 9.4°C; Dry bulb = 10.0°C

An example of polygons. The land is the southwest corner of Ukolnoi Island. Note how the polygons nearest to land somewhat follow its contours. Remember, these are uncharted waters.

Science and Technology Log

If you have spent any time reading the Ship Logs from other Teachers at Sea, you are probably familiar with the fact that each involves a different type of work. On Rainier, we are focused on conducting hydrographic surveys. This means that we collect data on the characteristics of the ocean bottom as well as the nearby coastline. We work seven days a week; from early morning and well into the evening. There are six launches (30 foot aluminum boats) on Rainier, each with a multi-beam sonar attached to the bottom of the hull. One of the launches has the capability to conduct surveys with side scan sonar. Each day, crew members work from what is called the POD (Plan of the Day). The POD is issued the evening before by the FOO (Field Operations Officer). Usually, four launches are sent out daily to collect multi-beam sonar data. On board are the Coxswain (drives the launch); the Survey Technician (in charge of data collection), the Assistant Survey Technician (AST) and the Teacher at Sea (me).

To give you an idea of what a survey day is like, here is a brief summary. Each day, the launch party is given a set of “polygons” to survey. A polygon is an imaginary closed area. You may remember this from geometry class. The polygons drawn on the working charts generally follow the contours of the islands. It is impossible for the Survey Technicians who created the polygons on a survey area or “sheet” to know how the contours look underwater. Why? Much of our survey work is in uncharted waters, which mean that no one has ever mapped the ocean floor in this area of Alaska. Thus, the work can be dangerous and every effort must be made to ensure the safety of all.

As the launch moves forward, the multi-beam projects a rendition of the ocean bottom in the form of a line (screen on right). I am taking a turn at making sure the beam remains within certain parameters (screen to right).

The coxswain begins by driving the launch near the area where we will start surveying for the day. Before we begin, we must take a CTD cast. CTD stands for Conductivity Temperature and Depth. The water’s salinity, temperature and depth can all affect the multi-beam data. The composition of the water column varies from location to location. Some areas may be affected by glacial runoff and therefore be fresher and colder at the surface than others, for example. Sound travels faster in warmer, saltier water, therefore; we must know the levels of each of these variables, as well as depth (pressure) in order to obtain an accurate set of multi-beam data. The CTD data is applied to the multi-beam data to correct for sound speed changes through the water column. This occurs later in Rainier’s Plot Room where all of the launch data is processed. Casts are made every four hours or before beginning an acquisition for the day.

After the CTD data has been downloaded the coxswain begins to “mow the lawn”. The launch is driven in lines that are as straight as possible, overlapping the previous pass a little so there are no gaps, or “holidays” between passes. As the launch moves forward, the multi-beam produces a series of pings which create a swath (a triangular shaped path of sonar beams). The widest base of the triangular swath is on the ocean bottom with the launch at the top. As the pings bounce back, they create various images that determine depth. The work requires constant adjustments and vigilance, since underwater features may present themselves at any time. We do not want to hit them. The area we were surveying when this shot was take was between 20 and 50 meters (greens and darker blues).

By watching the swath, the technician and coxswain can determine the approximate depth below, including any features like rocks, shoals, or underwater peaks and valleys. If you use a ROYGBIV (rainbow) color scheme, the points closest to the surface(less than 8 meters) show up in red. The more submerged the features or ocean bottom are, the more the colors move toward the deepest blue. For example, the lightest greens begin the depth range at 20-35 meters. This is especially helpful where there is no previous data. Can you think about why a coxswain might be very interested in knowing the places where the colors on the screen are turning from green to yellow to orange?

When a polygon is finished, it should look like it has been “painted in” with colors representing various depths and features of the ocean bottom. After completing a polygon, the data is saved and we move on to another polygon; take a CTD cast and start the whole process all over again. We return to Rainier by 16:30 (4:30 pm) unless weather and sea conditions are favorable, in which case the FOO can decide to run late boats until 17:30 (5:30 pm). The data is then handed over to the Night Processing crew who apply filters and correctors to the raw data. The tide and sound velocity are the main culprits in skewing data. In addition to tide and sound, things like bubbles in the water, schools of fish and kelp beds (of which we’ve seen many) can also affect how “clean” the data is. This is just a preliminary check. If the data is bad, we have to go out and survey the polygon again. After many days (sometimes weeks and months) of processing and checking, the data is used to create high-resolution, three-dimensional models of the ocean floor (on paper or computer). These models will eventually leave Rainier and will be used by NOAA’s Pacific Hydrographic Branch to create nautical charts for mariner’s use.

The CTD is lowered on a winch at 1 meter/second. After retrieving the CTD, I prepare it for downloading.

Personal Log

I feel like I’ve been on Rainier for a long time, even though it’s only been six days since we left the dock in Seward. There is a definite routine established from when I wake up at 06:15 until I go to sleep around 11:00. My head is bursting at the seams with new knowledge and things to remember and keep straight. It’s great to be a student again—everything is new. The technology component of Rainier’s mission is nothing short of mind-bending. How the survey technicians can keep all of the programs and how to use them straight, I don’t know. I have pages of “cheat sheets” to use to help me remember what to click on and in what order. Anyone who loves technology would love the job of survey technician. This is especially true here in the Pavlofs where you might be the first person to discover an interesting underwater feature or maybe a shipwreck. That would be “wicked cool”, as my students would say.

I have been on three different launches with three different teams. I bring this fact up because, although each team has the exact same goal in mind (collecting accurate hydrographic survey data), each individual tackles the tasks somewhat differently. For example, one coxswain might like to maneuver the launch so that the edge of the multi-beam sonar’s swath touches the inside edge of the polygon. Another might make their first line by maneuvering the launch straight up the middle of the polygon’s edge. Another example involves how survey technicians control the parameters of the multi-beam. Some like to adjust the settings manually and some like to use the auto pilot.

Did You NOAA (Know)?
RAINIER is operated by officers of the NOAA Corps. NOAA Corps is the smallest of the seven uniformed branches of the U.S. Government. It can trace its roots back to the presidency of Thomas Jefferson, who, in 1807, signed a bill for a “Survey of the Coast”. This eventually became the Coast and Geodetic Survey. Men were needed to commit to long periods of time away from their families to survey the growing nation’s waterways and coastlines. Instead of using multi-beam sonar, they lowered lead weights on ropes marked off in increments to measure ocean depth called leadlines. To watch an excellent movie on the history of NOAA and surveying, go to the website.

Alaska Fun Facts
On the Wosnesenski Island, we have seen many feral cows. According to some of the crew, there once was a homestead on this remote, treeless island. When the family left the island, the cows remained. No one takes care of them. There are other documented feral cow herds on other islands in the Aleutian Chain, including Chirikof Island, near Kodiak Island. Do you think you would like to live on an island that has no trees? Why or why not?

June 29, 2009April 5, 2021

Jill Stephens, June 29, 2009

NOAA Teacher at Sea
Jill Stephens
Onboard NOAA Vessel Rainier
June 15 – July 2, 2009

Mission: Hydrographic Survey
Geographical area of cruise: Pavlov Islands, AK
Date: June 29, 2009

Weather Data from the Bridge:
Position: 55°13.516’N 161°22.812’W
Scattered clouds with 10 miles visibility
Wind: 195° at 14 knots
Pressure at sea level: 1023 mbar
Temperature: Sea; 7.8°C Dry bulb; 13.3°C; Wet bulb; 11.1°C

Assistant Survey Technician, Todd Walsh, and I release the bottom sample that was collected from the sea floor.

Science and Technology Log

Today was another awesome day at sea. The ship picked up the anchor at 0830 to begin our move to a new anchorage. The plan for the day called for bottom sampling while in transit to the new anchorage. Bottom sampling is used to determine the composition of the sea floor. The bottom sampler is attached to a winch with the cable run through a boom to move the sampling device over the starboard side of the ship. The bottom sampler has a bucket that is designed to close when it hits the bottom, collect a sample of the material on the seafloor, and then it is brought back to the surface. The bucket must be secured and locked in place prior to lowering it to the bottom. The operation requires two people manning the device and examining the specimen and another person operating the winch.

The bottom sampler is ready to be deployed to collect a seafloor specimen.

The bottom sampler is opened once it is back on deck and examined by survey technicians. The sediment is observed for color and felt to determine texture elements. Most of the samples examined today were determined to be green sticky mud or volcanic ash and broken shells. This form of sampling provides information about the seafloor that will be of importance to ships that might consider anchoring in the area. Samples are sometimes collected for more extensive study.

While the people on the fantail are examining the sea floor samples, personnel in the plot room prepare to enter the information into the computer. The plot room crew enters the GPS location into the computer plus all descriptive data regarding the samples from the sampling crew. If the sampler returns to the surface in the open position, the sample is determined to be unsuccessful and is repeated.

Sitting in with a night processor allowed the opportunity to review data collected during the day and clean out noise that prevents the computer from selecting the best representation of the sea floor.

Personal Log

Working the bottom sampler and feeling the sea floor sediment was exciting for me. I thoroughly enjoy working with soils to determine various characteristics, so this activity was right up my alley. Although the sampler itself can be managed by one person, it is easier and safer for two people to operate the sampler while a third person operates the winch and boom. My partner and I worked together very efficiently and processed between five and ten samples during one shift. The shifts were divided into one and a half hour periods. I was lucky enough to get two sampling shifts and one shift in the plot room recording the data.

After dinner, I was able to work with one of the night processors to convert and clean data that was collected on one of the launches during the day.

Animal Sightings

A baby crab and a worm were found in some of our bottom samples.

June 28, 2009April 5, 2021

Jill Stephens, June 28, 2009

NOAA Teacher at Sea
Jill Stephens
Onboard NOAA Vessel Rainier
June 15 – July 2, 2009

Mission: Hydrographic Survey
Geographical area of cruise: Pavlov Islands, AK
Date: June 28, 2009

Weather Data from the Bridge
Position: 55°08.501’N 161°41.073W
Visibility: 10+ nautical miles
Wind: 250° at 12 knots
Pressure: 1024.1 mbar
Temperature: Sea 8.3°C; Dry bulb 10.0°C; Wet bulb 7.8°C

The device that collects the information for the Moving Vessel Profiler is referred to as the “fish.”

Science and Technology Log

The day began a bit overcast as Shawn Gendron, Manuel Cruz, Dennis Brooks and I set out in RA 4. Manuel is working on his HIC qualification, so he ended up running the equipment and the boat quite a bit today. The process involved in attaining the Hydrographer in Charge certification takes approximately one year to complete. To become HIC qualified, you must complete the HIC workbook and demonstrate proficiency in all areas of hydrography covered by NOAA in addition to demonstrating boat handling skills. (I could probably get a few things checked off myself!) Manuel handled the first cast by himself, then allowed me to help with the second cast, and complete the third cast on my own.

The MVP can be controlled with buttons located on a handheld wand. See it my hands?

The data retrieved from the casts was good and so there was not a need for any recasts. We have been trying to perform a cast at the beginning, middle and end of the day to provide adequate information regarding depth, temperature, and salinity. It is also necessary to take casts from various locations within the work area in order to accumulate necessary information to integrate with the raw data from the multi-beam sonar to depict the contour of the sea floor. We were supposed to use the MVP, Moving Vessel Profiler, today instead of the CTD. When we attempted to start the equipment, an alarm sounded and would not shut down. The computer also lost communication with the “fish.” (The fish is the data collection device that is placed in the water.) The MVP is similar to the CTD, except that it has a different top and is attached to a cable that extends beyond the stern of the boat. The MVP collects the same information as a CTD, but instead of a snapshot at selected locations, it can provide continuous depth, conductivity, and temperature readings by automatically taking repeated casts.

After our return to the ship, the MVP system was reviewed by the Field Operations Officer. The operating instructions were reviewed and it was determined that some key steps were not represented correctly. These omissions were corrected. The launches all have laptops that are being used to convert files from Hypack into Caris. Converting the files on board the launch allows hydrographers and survey technicians the opportunity to review the seafloor surfaces searching for areas of incomplete coverage. Shawn converted some files and gave me the opportunity to practice cleaning away errant returns or “noise.”

The unit pictured above is one of the two desalination systems for the ship.

Personal Log

Tonight after supper, Mary Patterson, (Teacher at Sea from Texas), and I went on a tour of the engine room with one of the engineers. I knew that the engines for this ship would be massive, but was unprepared for just how massive they are. NOAA Ship Rainier was put into commission in 1968 and still has her original engines. The engineers pride themselves on the excellent maintenance that has enabled the engines to continue to perform well.

All of the ship’s power and freshwater originates in the engine room. The ship has two generators that can be used to provide electrical power to the entire ship. Electrical outlets, radar, sonar, computers, and lights are among the items that use the power supplied by the generators. Normally, only one of the generators operates at a time and sometimes when in port, the ship is able to connect to shore power and shut down both generators.

A necessity aboard ship is a continuous supply of potable water. The ship has two desalination systems located in the engine room. Sea water is taken into the system under pressure and exposed to heat within the unit. The evaporated water is collected in trays and sent on to be treated with purification elements. The salt residue is then returned to the sea. Each unit has the capacity to produce approximately 150 gallons of fresh water per hour.

Question of the Day

How does the desalinization technology of 1968 compare to desalinization technology today?

June 23, 2009April 5, 2021

Jill Stephens, June 23, 2009

NOAA Teacher at Sea
Jill Stephens
Onboard NOAA Vessel Rainier
June 15 – July 2, 2009

Mission: Hydrographic Survey
Geographical area of cruise: Pavlov Islands, AK
Date: June 23, 2009

Weather Data from the Bridge
Position: 55°08.576’N 161°41.010’W
Visibility: 10 nautical miles
Sky: broken clouds
Wind: 230° @ 10 knots
Sea: 0-1 feet
Pressure: 1009.3 mbar
Temperature: Sea 6.1°C; Dry Bulb 8.9°C; Wet Bulb 7.8°C

The CTD sits near the surface for two minutes to acclimate to the environment and begin collecting data. The instrument is then lowered to the bottom and retrieved using the winch. — The CTD sits near the surface for two minutes to acclimate and begin collecting data.

Science and Technology Log

Ian Colvert, Martha Herzog, and Matt Abraham are my team for today. We are working in area that has not had any survey lines run yet. We are the first to explore what lies beneath the water! The survey that we are conducting today will involve running long lines instead of filling in polygons. The long survey lines provide the survey techs with an idea of what to expect for the area and assist them in planning the polygons that will be covered later. If rocks are known to exist, these first lines go near to them in an effort to determine bottom features at a safe distance.

The Reson froze twice today for some reason, but was able to start right up again. This issue was brought up at the daily meeting and it appears to have happened on another launch as well. (The ship is in frequent contact with the company and will have a solution to this problem quickly.)

The instrument is then lowered to the bottom and retrieved using the winch.

Personal Log

I was able to pilot the launch for a complete line today. I am proud to say that after learning to orient the boat using the information on the screen, I did a good job. After the first cast of the CTD, Martha and Ian let me go ahead and perform the next two casts of the day. The data collected from the casts was good, so we did not have to perform any recasts.

Ian made a couple of movies of the Reson data today that I will be able to take back to my classroom. I went ahead and took pictures of the side scan display to show students. I am going to go ahead and use my digital camera to make a movie of the side scan screen. Hopefully, it will work.

In the area that we surveyed today, there is a huge, interestingly shaped rock. As we passed by the rock, we noticed light colored areas along the rock. These light colored areas were seals. It was an impressive sight!

Animal Sightings

More than 30 seals

The light brown areas near the base of the rock are actually seals.