tidal gauge – NOAA Teacher at Sea Blog

September 21, 2011April 28, 2021

Kaci Heins: September 19-21, 2011

NOAA Teacher at Sea
Kaci Heins
Aboard NOAA Ship Rainier
September 17 — October 7, 2011

Mission: Hydrographic Survey
Geographical Area: Alaskan Coastline, the Inside Passage
Date: Wednesday, September 21, 2011

Weather Data From The Bridge

Clouds: Overcast
Visibility: 4 miles
Wind: 20 kts
Waves: 0-1 feet
Temperature
Dry Bulb: 11.7 degrees Celsius
Barometer: 1000.1 millibars
Latitude: 55 degrees North
Longitude: 133 degrees West

Science and Technology Log

Today was the first day that the survey launches left the Rainier to install and recover benchmarks and a tidal gauge. The weather was not great and the crew had a lot of work to do so I was not able to go with them this time. A benchmark is a small brass disk with information inscribed on it that relates to the station it represents. The benchmark holds the height of the datum. The purpose of setting a tide gauge is to measure the water level. The water level information is used to reduce the bathymetric data acquired to the chart datum (mean lower-low water, MLLW). Finding benchmarks has become quite popular through the hobby of geocaching. This is where participants use latitude and longitude within Global Positioning Systems (GPS) as a way to hunt down “treasures” hidden by other participants. This also includes finding benchmarks.

I’ve been trying to head up to the bridge as much as I can to learn as much as I can during this Teacher at Sea experience. The first time I went up at night I had no idea about the environment that the officers work in on the bridge. At night the officers on the bridge actually work in complete darkness. All of the computer screens have dimmers or red filters so that the least amount of light affects their eyes in the darkness. The reason it is so dark is because the officers need to be able to see the lighted navigation buoys to stay on course and to spot the lights of other ships that are heading in our direction. There are also one or two deck personnel that are lookouts either on the flying bridge or bow to keep watch for ships, lights, and other objects that could potentially be a hazard to the Rainier. A flying bridge is usually an open area above an enclosed bridge where the ship’s officers have a good view of everything around the front and sides of the ship. We are traveling through the Inside Passage off the Southeastern coast of Alaska, which is extremely narrow in some places along the way. This means that it is very important that the officers know exactly where they are and what is around them.

Personal Log

I have been able to do some other neat tasks on the ship while the majority of the crew were out on their launches. We finally were able to find a place to anchor at Ulloa Channel because we had a good “bite” with the anchor–it is protected somewhat from the weather we are dealing with, and it is close to our tide station. They also let me run out some chain for the anchor and I was able to practice using the crane on the ship. However, the best part so far has been being at the helm, or the steering gear of the ship. I will admit I was pretty nervous the first time I grabbed the wheel because it was at night so I couldn’t see hardly anything. Today, the officer of the deck (OOD) let me at the helm again because we were in open water. When I am at the helm I have to watch my gyro-heading, which shows me true North, and my magnetic compass, which is more of a back up if the electronic gyro-heading fails. If I have a heading of 150 then I have to make tiny adjustments or corrections to try and stay on or close to that number as possible. Even when I make the tiniest adjustment I can see how much the ship moves. I did start getting the hang of it and one officer even said he had never seen a visitor do so well!

One other item that I will mention in this blog is that the weather in Alaska during this time of year is overcast, rainy, and cold.

Canada — Beautiful Scenery Along the Inside Passage

However, going into this I had an idea of what to expect and I enjoy the fact that I get to see the non-glamorous side of this type of work. It does not matter if it is rainy, cold, what you are wearing, or what you look like because there is a job to do. It has been overcast every day, but the pine trees are amazing shades of green and the pictures do not do them justice. We have also had 15 foot waves and 115 knot wind (this is the same as a category 3 hurricane!). The wind didn’t bother me as much as the waves did. I thought it was fun for the first 30 minutes, but then I had to lie down for a while because I wasn’t feeling too well. I never threw up, but it did become uncomfortable. Now that we are anchored and have stopped moving I feel funny because my body has been used to moving around so much for the past three days. I sure hope I don’t get land sickness when I am done with this cruise!

Student Questions Answered: Here are student questions answered about feeding so many people on a boat over 3 weeks time.

Animals Seen

Puffins

Questions of the Day

We experienced 115 knot winds Monday night. What category hurricane would that be the equivalent to? Use the website if you need help.

http://www.nhc.noaa.gov/sshws.shtml

June 8, 2009April 5, 2021

Susan Smith, June 8, 2009

NOAA Teacher at Sea
Susan Smith
Onboard NOAA Ship Rainier
June 1-12, 2009

Mission: Hydrographic survey
Geographical area of cruise: Trocadero Bay, Alaska; 55°20.990’ N, 33°00.677’ W
Date: June 8, 2009

Weather Data from the Bridge
Temperature: Dry Bulb: 13.9°C (57°F); Wet Bulb: 12.2C (54°F)
Cloudcover: Overcast 8/8
Wave Height: 0-1
Visibility: 10 nautical miles
Wind: 325, 4 kts.
Sea Wave Height: 0-1
Sea water temperature: 12.2°C (54°F)

Science and Technology Log

Before I explain the science we did today, I will answer the question posed on log number 3: What is a patch test and why is it run? A patch test is used to find offsets in sonar setup (continuous errors) and timing errors. It is done whenever physical alterations occur with the sonar. Such problems can occur when it is mounted skewed, or not in perfect line with the ship.

The Patch Test checks pitch, roll, and yaw. The ship is run out from the shore and back into shore, along the same line. The computer has all offsets set to zero. A swath is sliced at the edge so the computer is looking at the outer beams from the side. With a roll offset it must be changed from an X pattern to a single, flat line. With a pitch offset, a nadir view is taken, the angle is adjusted until the two lines (one out from shore, one into shore) form a single straight line. Yaw also has two lines offset so they must be combined to one line configured identical to the two lines. The Patch Test takes approximately one to two hours to complete.

Today I was involved in obtaining data relevant to tides. We used a tide gauge, levels, GPS, and a staff placed in the water, with a nitrogen being pumped under it. The tide gauge measures the unit of pressure it takes for a nitrogen bubble to be squeezed out. The greater the amount of water covering it the greater pressure is required to release a bubble. To get water depth, someone reads the staff water level and continually records this information for three hours. This will enable us to know the difference in the pressure gauge readings and the staff water level. A Global Positioning System (GPS) is used to determine where the staff is by getting a good constellation (satellites in orbit) reading.

It was my job to hold a level rod on the primary benchmark location while someone else recorded measurements using the surveyor’s level (The level rod is measured in centimeters). The surveyor’s level has three lines, or stadia, inside the level. These lines are read as upper, middle, and lower. I placed a smaller bubble level against the rod to make sure it was straight up and down. Once my location was recorded a second person, also holding a level rod, placed hers on a staff (a triangular wood structure) set in the water. The surveyor’s level was disturbed, then a second reading was taken at the staff, and a second reading was taken at my benchmark. If the numbers did not match within a certain range, or historical data, the measurements had to be repeated.

We went through this process for five benchmarks. These benchmarks were placed in specific locations based on elevation and stability of the ground above high tide level. This procedure is completed to ensure the benchmarks and the staff have not been moved, by either human disturbance or a natural occurrence, such as an earthquake. As a side note, in some locations these benchmark rods have had to be drilled down 125 feet. In the Arctic they may be drilled 25 feet into the permafrost. When drilling the holes for the benchmarks care must be given to ensure the surface is smooth, not skewed, or at an unusual angle.

Sometimes a temporary benchmark, called a turtle, must be used. This is a small, heavy, circular piece of equipment, which can be placed anywhere solid. The person holding the staff can turn all the way around it to allow for different measurements. All data collected in this activity are sent to NOAA’s tides office.

Personal Log

After viewing the ship’s photography server I have become interested in what actually goes on in the dry dock. The dry dock is in Seattle where the ship goes for repairs, restoration, and refitting. After the launches and other things are removed from the ship it goes to the dry dock. Gates close off the ends. On the floor of the dock are blocks for the ships hull to sit on, placed exactly in line for this particular ship. Divers go down to check for precise placement before the water is drained. The ship is tied to the dock to stabilize it (prevent it from tilting or falling off the blocks) and if you are not off the ship before it goes into dry dock you are not getting off anytime soon! On the hull are numbers used to identify the ship’s sections. When it is being retrofitted the workers must know where each section came from so the ship can be put back together correctly.

Tape where the symbol and number were painted

Underside of ship on the blocks; the black hole is on for anchor storage

Dry dock operations can take from two months to over a year, depending on the work needing to be done. Crew stays on board as long as possible. When berths are being refurbished they stay in local hotels. Other personnel either work on other NOAA ships or go to other project sites. (All dry dock photographs courtesy of Rainier picture server)

For more information visit these sites:

http://www.osha.gov/SLTC/shipbuildingrepair/drydocking.html http://en.wikipedia.org/wiki/Dry_dock (has history of ancient dry docks)

August 20, 2008April 5, 2021

Patricia Donahue, August 20, 2008

NOAA Teacher at Sea
Patricia Donahue
Onboard NOAA Ship Rainier
August 19-23, 2008

Mission: Hydrographic Survey of Bear Cove, AK
Geographical Area: Kachemak Bay, Alaska, 59.43.7 N, 151.02.9 W
Date: August 20, 2008

Weather Data – Glorious!

Science and Technology Log

A black bear comes to inspect what the land party is up to!

WOW! That says it all. Today’s big excitement was supposed to be the leveling of the tidal gauge and the survey work in the cove. The bigger thrill – and scare – was the bear that approached to within 30 feet of me as I was standing over a benchmark with a leveling rod. Remembering the safety rules about bears, I stayed calm and alerted the others. Then I put down the pole and walked away slowly. Fortunately it was a young and smallish black bear who was easily scared off by the Commander throwing rocks. We were all on our guard the rest of the day. There were several benchmarks to check. Some of the climbing was perilous. All of the work had to be done at low tide. The survey data was collected and I look forward to seeing what’s done with it.

During the afternoon, another emergency drill took place and I was invited to watch. In the scenario, the bridge lost the ability to steer the ship. Control of the vessel had to be made from aft steering, below decks where the rudders protrude from the vessel. By using only a compass and steering orders given in degrees, the helmsman maneuvered the ship. There were no windows or other indicators of the ship’s position. To make matters worse, the scenario called for a loss of communications so a sound powered phone that uses only the energy from the speaker’s voice to operate had to be used instead.

By late afternoon the ship moved to its new anchorage a few miles from Homer. I was invited to watch the lowering of the anchor. The anchor weighs 3500 pounds and there are two of them. Each length of chain weighs 1200 pounds and there are a total of 12 lengths for each anchor. Today we used only 5 sections of chain and 1 anchor. Each section of chain is 90 feet (15 fathoms) long. The anchor is lowered while the ship is in reverse.

Personal Log

My family and my students enjoy a game called geocaching. We’ve started by using hand held GPS devices to find benchmarks and eventually we’ll move on to finding caches and creating our own. I’ve only ever seen old benchmarks but today I saw brand new ones. One of the officers even showed me how they’re made. Benchmarks indicate the exact location and height above sea level of that particular place. The Chief Steward took me to see the food storage facilities. The freezer is enormous! The ship carries enough food to last for 6 months, although the fresh fruits and vegetables only last for one month. They have more food than CostCo!

Animals Seen Today

Stellar’s Jay, Black Bear, and two species of Jelly Fish

Question of the Day

How long is the anchor chain on the Rainier? Provide your answer in feet and fathoms. How much do the anchors and the chain weigh altogether? Why is the boat in reverse when the anchor is dropped?

Challenge Yourself

Go to http://www.geocaching.com and type in your zip code. Identify a benchmark near your home. Find it and take a photograph!

June 16, 2008April 2, 2021

Mark Friedman, June 16, 2008

NOAA Teacher at Sea
Mark Friedman
Onboard NOAA Ship Rainier
June 8-20, 2008

Mission: Hydrographic Survey and ocean seafloor mapping
Geographical Area: Southeast Alaska
Date: June 16, 2008

Here I am studying nautical charts as preparation for the Tidal Gauge expedition.

Science and Technology Log

Each day the RAINIER’s “Ship’s Officer,” in collaboration with the field operations officer and the ship’s commander, issue a “Plan of the Day” also known for short as the POD. (Who knows what marine animals move in groupings called a POD? First one to reply from Los Angeles gets a free Alaskan souvenir!) The POD contains important information such as, for Sunday, June 15, Sunrise was at 0415 (4:15 am), and sunset is at 2139 (9:39 pm!) It will be a long day! I rise at 6 am to read the POD and find my assignment.

POD Revelations
The ship’s position is: Anchored, Palisade Is., AK. The POD also has tide levels, U.S. Coast Guard beacons in the area, the weather, and who the officer on duty is. The weather you ask? How important, especially because many of us are going out on launches and the smaller skiffs for specific assignments. The launch drivers need this especially to make sure all operations are safe. The winds are mild, coming in from the south at 5-10 mph, cloudy with showers, air temperature a balmy 51F with seas of 1-2 foot waves.

The POD has major assignments for anchor watch and officers on duty. Safety is a constant refrain as there are anchor watch positions around the clock to staff the bridge (command center) sending regular weather reports to the Coast Guard and National Weather Service and maintaining a secure and safe environment. The POD also lists all the assignments for the launch vessels being dispatched by the mother ship—no not Battlestar Galactica or the Enterprise, but the RAINIER. Today two vessels will be doing sonar readings around San Christoval Channel and North San Fernando Island. The other two, one of which I will be on, is going to remove a tide gauge and do a recon (reconnaissance) mission for a new tide gauge location.

The Journey Begins

Here I am learning to withstand the cold in my Arctic survival suit.

7 am- We are all up for a hearty breakfast, made by three talented chefs (especially in the omelet, soup and dessert department).

7:30am- I struggle into my arctic survival suit and boots in preparation for a “wet landing.” I feel like Sylvia Earle in her “Jim Suit” as I waddle like a penguin to the stern of the ship to board a skiff for an hour journey up narrowing channels and over rapids to reach our destination. (I have put on all layers of clothing that I brought with me from Los Angeles, preparing for frigid temperatures and lots of wind and mist en route.)

8:30 am- With a spraying salt mist and a wind chill factor making the temperature about 20 degrees Fahrenheit, we race up the labyrinth of islands and channels to our destination. A deer and her fawn stare blindly at us on our port side, a humpback whale breaches on our starboard. We even glimpse a couple of sea otters playing/rafting in the kelp.

On Location
9:30 am- We have reached the tide (marine), or water level, gauge. Our assignment is to remove it after ensuring calibrations have been correct. The tide is coming in and the shore is covered with algae, mini-white barnacles, a sprinkle of clams, a species limpets and small purple mussel beds which are thriving.

What is a tide gauge and why are they important?
Water level gauges are instruments to measure water surface elevation over long and short durations of time. They have been used for centuries by mariners to improve their knowledge on the depth of water and apply this information to the chart. This information can aide in the calculation of tidal currents, the ebb and flow of water as the tides change. More modern gauges need a power supply to relay information via satellite to appropriate organizations interested in this data.

A tide gauge consists of a number of instruments including, foremost, a measured, calibrated staff that is securely mounted into rocks to give a visual baseline of water levels. It is connected to benchmarks by using a survey instrument called a level, which optically measures height differences on a survey rod, which I held during the operations. Benchmarks used by NOAA, and previously by the U.S. Coast and Geodetic Survey, are brass survey discs (see photo right) that are imbedded into bedrock and stamped with a code that correlates in NOAA data banks to date of installation, project, location number, etc. Five of them are traditionally imbedded at various locations in the vicinity of the staff. They are leveled between each other and the staff, establishing a mathematical correlation. Gauge measurements are all related to the benchmarks, which hold the permanent datum for the tide station.

The Underwater Component

NOAA divers retrieve a submerged tidal gauge

Another component of the gauge is an orifice (brass pipe with an open end) that is placed where it is continually submerged. It is connected to an electronic readout instrument via strong plastic tubing that is filled with nitrogen. As the gas comes under more or less pressure, based on the pressure exerted by the quantity of water pressing down upon it (water pressure), it registers the height of water levels. (Similar to how air pressure is registered by a barometer, a little remembered instrument but critical to meteorological forecast and studies).The information on depth is thus recorded and electronically transmitted out of the area thru solar powered equipment. In addition to water levels for meteorological (weather) purposes, over time these tidal gauges, when coordinated with others and register actual sea level rise which is now occurring more rapidly due to glacial melting from global warming. They have also been used to register tectonic plate movements. We disassembled the land equipment after completing our benchmark surveys. Later we scouted for a new location further south for a new tidal gauge and benchmark installation site. Then the divers went into action (see above photos). Their job was to retrieve the submerged gauge and piping for future use. In the process they took a video of part of the undersea flora and fauna.

Back on the Ship

All equipment is secured, checked and prepared for the next installation site. The gauge team tomorrow will secure benchmarks for the establishment of a new tide gauge station. (Guess what? At the installation site they found a 1927 benchmark still intact and functional!!)

A sun star, a type of sea star, was observed during the tidal gauge dive.

July 27, 2007April 1, 2021

Ginger Redlinger, July 26–27, 2007

NOAA Teacher at Sea
Ginger Redlinger
Onboard NOAA Ship Rainier
July 15 – August 1, 2007

Mission: Hydrographic Survey
Geographical Area: Baranof Island, Alaska
Date: July 26–27, 2007

Weather Data from the Bridge
Visibility: 10 Nautical Miles
Wind directions: 110°
Wind Speed: 10 Knots
Sea Wave Height: 0-1 feet
Seawater Temperature: 14.4° C
Sea level Pressure: 1012.9 millibars (mb)
Cloud cover: Cloudy
Temperature: 16.7° C, (62° F)

Mariner Word of the Day: Scuttlebutt. A scuttlebutt on an old sailing vessel was the barrel where drinking water was stored. People would gather and talk casually, or gossip, as they drank water. This led to the second definition of scuttlebutt, “a rumor.”

ENS Pereira, Divers-Physical Scientist Campbell and LT Yoos, Coxswain O’Connor review safety checks and dive plan.

Science and Technology Log

We moved the ship from Steamboat Harbor to Bocas de Finas near Bush Top Island because winds were picking up. The ship is safer when it is not anchored in a high wind area! Weather matters a great deal when you are working on the water. Winds contribute to sea waves, swell heights, and can create less-than-ideal conditions for hydrographic surveying. Weather is taken into account in planning when, and where the ship will travel to work. It also determines what should be done first. Specifically, determining the day’s priorities can depend on what time the winds and seas are expected to change. While seaworthy vessels can work effectively in rough waters as is sometimes necessary, knowing when the water will be rough makes for better planning. What I have come to appreciate on this ship is the accuracy of the weather predictions aboard the RAINIER. If the Orders of the Day (OOD) read that it is going to rain – it rains. If it tells me that there will be swells in the afternoon from 3 to 4 feet – there are! Now I don’t know about you, but I have noticed when I am at home the only accurate weather forecast I get is when I look out the window.

What is it about the weather information that is used on board that makes it so reliable? First, there are many sources of information about the weather that are available, and second, they use them! The Officers on board know a great deal about the earth, from surface to upper atmosphere, so they know what information is necessary for a good analysis. There are many resources available to the RAINIER that you can access too. For example, there are text-based discussions of the weather based on the use of different global models, there are local forecasts, there are infrared satellite maps updated every 30 minutes so you can see where clouds are forming and how they are moving, there are also satellites that collect data in order to show the visibility spectrum, or how much light is available –every 30 minutes. (It tells you the amount of radiant-light energy entering the area.) Another is QuickSCAT that creates a chart of the wind’s movement in an area (with lots of small arrows) so you can see exactly what directions it is moving (wind swirls and moves like water around rocks – it doesn’t just go in one direction all the time!). Lastly, there are grids that tell you the extent of high and low pressure systems, how strong they are, and where they are likely to move. Pressure systems impact the direction of the winds, and their strength.

Sporting Goods - Craig, Alaska — Sporting Goods – Craig, Alaska

With all of this information, you can take into account many variables that affect navigation: visibility, wind speed and direction, cloud cover, precipitation (which also impacts visibility), water movements, (direction and speed of waves, and swells). I should also add a non-weather related variable that impacts planning – tides. Considering all these variables together helps predict conditions in order to choose the best time of day to complete work, and move vessels through the water SAFELY! As everyone starts their day they know what to expect so they are well prepared.

Website for weather information related to the RAINIER’s work (thanks to CO Noll):

Marine Forecasts Homepage
Offshore Forecast for Southeast Alaska
National Weather Forecast Discussion Page (with glossary hyperlinks):
Coastal Zones of Southeast Alaska
GOES Infrared satellite (good for clouds)
GOES Visible spectrum satellite (good for sun)
British Columbia forecasts
QuickScat (Wind direction and speed)

And graphics:

Pacific Profiles – Predictive Charts
Local Higher-resolution grids (experimental)

Survey Tech Krynytsky and ENS Villard-Howe (Navigation Officer) gather and examine bottom samples.

Yesterday’s work

Tide Gauge check – Nossuk Bay. We traveled to Nossuk Bay to inspect a Tide Gauge, as it was not sending data correctly. Tide gauge inspections require SCUBA (Self Contained Underwater Breathing Apparatus.) The divers were going to 40 feet below the surface. The pressure is greater underwater every 33 feet, so it is harder to move and to breathe. A specialized crew is sent for this job since it requires specific training in order to execute perfect communication, keen observations, and precise movements of the boat.

After ensuring the underwater section was working properly attention shifted to the land-based components. The crew, except the coxswain, went ashore to inspect the rest of the equipment. Since we noticed fresh bear sign in the area, we talked loudly and kept our eyes open. After everything checked out ok we returned to the ship. I had fifteen minutes to eat lunch and return to the boat for sediment surveys and a run to Craig, AK to pick-up two officers joining the RAINIER for the trip back to Washington. One is a Junior Officer returning to the RAINIER for the trip back to Sand Point. The other is the new Commanding Officer, who will be replacing CO Noll. CO Noll’s commission with the RAINIER ends with the completion of this journey.

Checking the transmission equipment to ensure it is working properly.

We gathered samples from seven different locations where ships and boats anchor when they enter Boca de Finas. Knowing the bottom type can ensure safe anchorage. Not knowing what the bottom is made of when you drop anchor can be dangerous. Surveying the bottom consists of dropping a line with a scoop to the bottom, and examining the contents once the sample is back on board. The contents are compared to a descriptive chart to be sure the correct classification is selected. This information will appear on NOAA charts to help navigators in this area.

Personal Log

The crew jests that the official footwear of Alaskans is a boot called XTRA TUF. When in Craig, we stopped in at the local sporting goods store and I noticed how neatly arranged everything was – with one exception – the boots in the picture below. I asked the man behind the counter about this and he said, “The contents of those boxes will be gone in the next 48 hours – so we don’t bother to mess with them. So I think the crew is correct. At about 10:00 last night, I asked ENS Villard-Howe some questions about ropes, navigation & direction vocabulary. We started to talk about all sorts of nautical topics. She went to her cabin and brought me three very important books – her top three if you want to know anything about maritime topics! The Eldridge Tide and Pilots Book (first written in 1854), American Merchant Seaman’s Manual, and The Ashley Book of Knots. (If anyone wants to get me books for my classroom – these are the three on my wish list! Young potential mariners and marine scientists can learn a great deal from them! )

We talked for another forty-five minutes. As we started to yawn in between sentences we said “enough.” (It wasn’t the company or the topic we were exhausted.) I have to admit, I felt like I was talking with someone who knows and loves the history, knowledge, and skills of her work. She has a true passion for maritime work and her work on the RAINIER.

For my students, I wish them the same level of passion for their endeavors and appreciation for the contributions and history in their yet-to-be chosen field. It is this kind of dedication that makes a great worker, teammate, and leader. There are many examples of this on board – I just happened to spend the later part of the evening exploring the depth of knowledge of one crewmember!

Personal milestone – Sea legs: I ate greasy-yummy pizza on the way back from Craig, AK (a small port town on Prince of Wales Island), while bouncing and rocking across 2-3 foot swells for an hour and it didn’t bother me one bit! : )

Question of the Day

Topic 1: What websites can you use to learn about tomorrow’s weather in your area? (Start from the ones that are listed above, and see if you can’t find the links from the SE Alaska sites to your local information.) What information is used to forecast weather in your area? Using the information on the website, try to forecast the weather tomorrow – (temperature, precipitation, general conditions.) See what the “news forecasters” say. Check to see how you did. What would you do different the next time you try to forecast the weather?

Topic 2: How do satellites gather satellite information? How many weather satellite systems are on the NOAA website? Where is the closest NOAA weather station in your area?

Topic 3: What is a Merchant Marine? Where do Merchant Marines work?

July 22, 2007April 1, 2021

Ginger Redlinger, July 22, 2007

NOAA Teacher at Sea
Ginger Redlinger
Onboard NOAA Ship Rainier
July 15 – August 1, 2007

Mission: Hydrographic Survey
Geographical Area: Baranof Island, Alaska
Date: July 22, 2007

One of five Geodetic Survey Benchmarks at Dorothy Cove

Weather Data from the Bridge
Visibility: 4 Nautical Miles
Wind directions: 190°
Wind Speed: 6 Knots
Sea Wave Height: 0 – 1
Seawater Temperature: 12.8° C
Sea-level Pressure: 1010.0 millibars (mb)
Cloud cover: Cloudy &
Rain Temperature: 13.9° C

Mariner Words of the Day: Port & Starboard

Port and starboard are directional words indicating the sides of the ship. As you are facing the bow (front) of the ship, port is on the left side, and starboard on the right side. How to remember? Port and left both have four letters.

Science and Technology Log

Today was the day that we wrapped things up in this area by re-surveying a few sections to improve the quality of the initial set of readings, took horizontal measurements of the water-level (by hand) in order to improve the accuracy of area mean tide (high and low) data, and prepared the ship to move south. I have written earlier about the attention to detail, safety, and teamwork in the day-to-day operations, the gathering and processing of data, and daily production of results. Today I am adding the noticeable value of the work done by NOAA vessels as noted by a gentleman and his family who came to watch our tide gauge survey crew work this morning. He said, “You people with NOAA do a great job, and the folks in Sitka use your information all the time. We are thankful that you have provided us with the information we need so we can enjoy navigating the waters around here.” That was a good way to start the day. I highly recommend that you read TAS Beth Carter’s description of mechanics and tools involved in Tide Gauge Surveys.

While it sounds easy, it is actually very challenging to collect accurate measurements to the specifications required for this work, which are to the millimeter. Everything has to be level and measured at precise locations using benchmark geodetic locaters installed. Using the same locations (the geodetic benchmarks) each time you take measurements ensures consistent use and interpretation of horizontal measurements. The horizontal measurements between the benchmarks tell us whether or not the land height has changed. This is important information to give context to any changes the tide gauge measures. If the mean tide level has changed, you need to know if the land level has changed too! Much of the data we gathered today is also connected to the GPS (Global Positioning System.) I have an old farmhouse and level is not a word I can use to describe most of it. Making a precise measure by establishing a level place on a slippery, rocky beach makes taking measurements in my house seem like a piece of cake! The survey scopes at the benchmarks are looking across about 50 feet of water to their left at the picture on the left (below) – which is the rod at another benchmark. The next picture is the rod at the third position, which would be on the beach about 90 degrees, and 50 feet to the left of the survey scope (and the same, but the right, of the rod on the other side. When the lines connect, we have a triangle!

If you would like to see how challenging this can be, here is a simulation that reverses the location of the surveying scope eyepiece (with the crosshairs) and the rod (with the height indicators), but it will definitely give you an appreciation for the challenge of accurate measurement over distance: Imagine yourself with a standard size metric ruler and a piece of paper with a crosshair pen line about 10 cm long each direction. About one centimeter from the top and the bottom of the vertical line draw another crossing horizontal line 2 cm long, about 1cm on each side. Tape the paper to the wall across the room and walk to the other side facing the paper you just taped to the wall. Now hold up your ruler an arm’s length away, vertically, with the 0 on the bottom so you are reading the measure up from the bottom of the lines. Close one eye. Try to identify exactly the millimeter at each horizontal line, for each of the horizontal lines. Could you line it up exactly? Was your ruler and paper both “level” so you could? Hard to see? Hard to measure? Now you see how challenging this can be! Imagine making an accurate measurement over a distance of 50 to 75 feet! It is also important to note that multiple measures must be taken that have to agree on the same result, with allowance for a tiny margin of error (again, a two millimeter margin of error is allowed – that is one millimeter error for the upper half of the cross hair and one for the lower half).

Here is another view of the survey scope lining up with the rod. If you look at the bottom of the rod you can see Geodetic Benchmark.

In the case of Dorothy Harbor, there are five Geodetic benchmark markers. When the line of sight is either obstructed, or too great to make an accurate reading, then a “turn point” is established. The turn point is set on a turtle (not a real turtle) which is a heavy disk that serves as set location upon which to balance the rod so measurements can be taken. Measurements must be taken from, and at, each location that needs the turn point to ensure that the data is correct. Since this data is used to ensure the accuracy of tidal data in this area, and to supply information to the GPS – it must be done correctly. In the natural environment, this is quite challenging. The measurements are recorded on a PDA and returned to the ship for processing. Right triangle geometry, simple algebra, or trigonometry can be used to determine the accuracy of the measurements at each point. If you have the markers at two line-of-site points (say to your right and your left) and are measuring the distance from where you are to each of the two points, you can figure out from your findings what the distance is between the two line-of-site points. By moving the rods to each of the five markers, you can verify that the measurements made from each location are accurate. Taking and using multiple measures is common sense to those who do it all the time like the NOAA crew. For many people, learning why is important. Some people learn it through building things — like the common sense rule to measure more than once before you decide to cut lumber, or to measure from two directions before you square a corner – you have to be sure you are right before you move to the next step!

Once we were done with our measurements we ate lunch, then began to disassemble the Tide Gauge measurement assembly. The divers came in later to remove the equipment anchored underwater, and everyone returned to the ship to prepare for the evening’s departure. The crew was exhausted as we had to climb, wade, carry, move, hold, disassemble, dive, and concentrate intently on our tasks. Tonight we head south at 2100 towards Ketchikan and begin surveying a different area tomorrow.

After helping the crew complete today’s work, I realized how difficult it is to gather precise measures by hand in dynamic, ever-changing conditions. (The wind picking up in the middle of a read — moving the 15’ high rods just enough to throw off the desired accuracy – so you have to start all over, the trees interfering with the line-of-site between the benchmarks and rods – people pushing back tree branches, trying to triangulate points on an unstable rocky beach, you get the idea…) Despite all these challenges, the crew gets the job done. This is what the navigating public (and commercial navigators), appreciate about NOAA’s work. As I heard, straight from the pilot and family of the Sitka-based pleasure craft anchored in Toy Harbor.

I also appreciated the seafloor mapping tools provided by the technology on the ship. What if we had to take seafloor readings by hand! (And hope that we had found all the submerged rocks!) I think technology for surveying has made mapping the seafloor easier, at least at the measurement stage : )

Question of the Day

Topic 1: How are navigational charts, topographical maps, and road maps alike? How are they different? (The answer to this question will be explored in the next journal).

Topic 2: Where can you find a geodetic benchmarks in your area? Outside of your area: What is special about the markers that are used in Disneyland (not created by the USGS)?

Topic 3: What are the tools and techniques of surveying?

June 27, 2007April 1, 2021

Beth Carter, June 27, 2007

NOAA Teacher at Sea
Beth Carter
Onboard NOAA Ship Rainier
June 25 – July 7, 2007

Mission: Hydrographic Survey
Geographical Area: Gulf of Esquibel, Alaska
Date: June 27, 2007

Weather Data from Bridge
Visibility: 6 miles
Wind direction: 034 degrees
Wind speed: 5 mph
Sea Wave Height: none
Swell Wave Height: none
Seawater temperature: 12.2 degrees C
Sea level pressure: 1017.2 mb
Dry Bulb Temperature: 12.2
Wet Bulb Temp: 11.7
Cloud cover, type: 8/8, stratus and cumulus
Depths: 31 fathoms

Researchers are kneeling in a sitka spruce forest as they check the computer that is collects and records tidal data on a small island in Nossuk Bay, Alaska. — Researchers are kneeling in a Sitka spruce forest as they check the computer that is collects and records tidal data on a small island in Nossuk Bay, Alaska.

Science and Technology Log

On Tuesday afternoon, June 26, I went out with a crew of researchers to check the equipment that collects tidal data for Esquibel Bay. There are six main pieces of equipment used to collect this data: 1) a cylinder of nitrogen, 2) a hose attached to the nitrogen cylinder that emits small bubbles of nitrogen into the water, 3) a computer that collects and records data, 4) a solar collector to power the computer’s battery, 5) a transmitter that sends the data to a satellite, and 6) the tide staff (an actual wooden staff in the water), and GPS benchmarks. The staff is set and readings taken so that the vertical measurements of the staff are linked to the benchmarks. The gage, which is officially a “tertiary” gage, is set up concurrent with a “primary” gage that has been acquiring data for over one epoch (19 years or more). Sitka, Alaska, is the site of NOAA’s primary gage, which has similar tidal characteristics to the area that we are working now. Thus, only an amplitude and phase differential must be applied to the Sitka gage to get a water level for this area. Without the staff readings, there would be no way to tie the “bubbler” level to the ground surrounding the gage site, and thus no way to recover the actual local vertical datum (water level) relative to the gage in Sitka.

The nitrogen cylinder slowly leaks bubbles through the hose, which are released into the water. When the tide is high, there is more water and pressure above the hose which makes it more difficult for the bubbles to escape the hose. When the tide is low, there is less water above the hose, and therefore less pressure, which makes it easier for the bubbles to escape. Readings are recorded digitally every six minutes, averaged every six seconds. Staff-to-gage measurements are also recorded every six minutes whenever the site is visited, and 3 hours’ worth are recorded at installation and removal, so that the vertical measurements of the station are effectively “tied” to the measurements at the primary water level station at Sitka. (Good Working Question: Download data from both stations and compare the two – are there differences? Next, compare Sitka and Ketchikan and Kodiak – are there bigger differences?).

ENS Meghan McGovern, Junior Officer of RAINIER, and Shawn Gendron, survey technician, position the tripod which will hold the transmitter to collect the GPS information needed by the RAINIER.

For some reason, the transmitter is not emitting signals that can be read by the satellite, and therefore by the scientists at NOAA headquarters. This is why the skiff took several technicians over to check the equipment to see if it is still functioning and recording properly. They downloaded the water level data to send to headquarters via email while also setting up GPS equipment so that an ellipsoidal (GPSrelative) height can also be linked to the orthometric (gravitational) elevation determined through water level measurement, and will return to the ship and process the GPS data. The tides are important to hydrographic surveying, because obviously, the water is deeper at high tide than at low tide. The goal is to collect accurate information on tides, and then combine that with the data collected by the launches, in order to get accurate depth information. The tide-corrected depths on the chart they want to show are relative to the mean low low water, which is the average of the lowest of daily tides taken over the last 19 years. On the Atlantic Ocean, tides are semi-diurnal. This means that there are two high tides and two low tides per 24 hours. But, on the Northeastern Pacific, tides are mixed. See here for more details.

Today, (Wed. June 27), the crew returned to the small island to check on the HorCon station, which stands for Horizontal Controls. The RAINIER established this water level station in April of 2007, and set into place 5 benchmarks which are tied into the international framework of benchmarks that make it possible to utilize GPS, or Global Positioning Satellites to determine one’s exact location. RAINIER’s researchers placed a receiver antenna on top of a tripod, which was positioned exactly above the center of the metal disc benchmark cemented into a rock. The antenna receives from some of the 11 Global Positioning System satellites that orbit the earth and constantly change their relative positions. For a final position to be accurate, at least four satellites must be recorded in two different sessions of more than six hours duration separated by at least one day. They connected the cables, turned on the GPS receiver and then waited for the satellite constellation (also known as the ephemeris) to be downloaded so that all available satellites could be tracked. The first satellite was tracked around 1 hour later, and then we left the island, as the equipment was to be left in place for at least 6 hours. When we returned 6 hours later, 8 satellites had made contact, and the recordings were noted and will be taken for evaluation onboard the ship.

Anna-Liza Villard-Howe, the Navigation Officer of the RAINIER, explained to me that the GPS measurements of benchmarks are being conducted in order to get as precise a determination of sea level as is possible, so that all the hydrographic information collected by the RAINIER can be referenced to the ellipsoid. Sea level has changed in Alaska in the recent past due to glacial rebound, which means that as the glaciers recede, the land is actually rising. Also, many large earthquakes have occurred in Alaska in the last century, which also changed the shape of some landforms and affected sea level readings. Online Sea Floor Mapping Activity Targets Kids (CED, OCS). In celebration of World Hydrography Day, NOAA’s Ocean Service Communications and Education Division, in cooperation with NOAA’s Office of Coast Survey, launched a new educational offering — Sea Floor Mapping — on the National Ocean Service Education Web site. It is designed for students at the 3^rd – 5th grade level, and the media-rich activity teaches young people about mapping the seafloor and why it is important. This activity also conveys information about NOAA’s missions of discovery and service. The Sea Floor Mapping Activity is available online here.

Questions of the Day

Why are tides in the Pacific and Atlantic different? What are the factors that affect tidal changes?
Look up a tidal chart for the inlet or beach nearest to your home. How far apart are the high and low tides?
Who (which country or countries/which agencies) is responsible for the maintenance of the 11 Global Positioning Satellites that are now orbiting the earth? If a satellite fails, would it be replaced? By what agency?

Personal Log

While on the tiny island, one of the officers carried a shotgun…in case we met a bear! I’m pleased to say we didn’t encounter a bear, but did discover animal scat, and two eagle feathers. One was a tail feather – beautifully white – and we didn’t collect the feathers because it is illegal to collect eagle feathers. We also saw 7-8 harbor seals on a rock outcropping. We tried to sneak up on them to get good photographs, but they bobbed and rocked and slipped into the water before we got very close. Also, on the island I was surprised to find many clumps of saltwort, which Eastern coast students (and my first grade class!) should recognize from the mud flat near the salt marsh. It tastes….salty! No surprise there.

On Wednesday, there were so many white gnats that we sent the skiff back to the ship for bug repellant. They were like No-See-Ems, only we could See Em and Feel Em! We built a small, smoky fire, which made things somewhat better. The highlight of the day for me was kayaking after dinner with the XO (Executive Officer) of the ship, and Ian Colvert, an assistant survey technician. We saw a rainbow and paddled through a misty rain, then sunshine…a beautiful evening.

August 27, 2006March 26, 2021

Barney Peterson, August 27, 2006

NOAA Teacher at Sea
Barney Peterson
Onboard NOAA Ship Rainier
August 12 – September 1, 2006

Mission: Hydrographic Survey
Geographical Area: Shumagin Islands, Alaska
Date: August 27, 2006

Intern Umeko Foster exploring the coastline of Cushing Bay on Mitrofania Island.

Weather Data from Bridge
Visibility: 10+ nm
Wind : light airs
Seawater temperature: 11.1˚C
Sea level pressure:1017.0 mb
Cloud cover: partly cloudy

Science and Technology Log

The personnel aboard the RAINIER are from a wide variety of backgrounds and locations. They come from the southern states, America’s Heartland, cowboy country, the east coast, and the Pacific Northwest. Many now call Seattle, RAINIER’s homeport, their home. What follows are brief profiles with some officers and crew members that I spent time with on the ship.

AS Leslie Abrahamson and I talked while she was splicing lines (working on ropes to keep the ends from fraying or unraveling). That is a fairly specialized skill and Leslie had ample time to practice while working for several years on Tall Ships. She was a teacher for over 5 years working with high school aged youths, in programs including widely respected Outward Bound. Following graduation from high school in Long Island, New York, Leslie attended Stanford University in Palo Alto, California to study theater arts. At the end of her 3^rd year she went to Shanghai and spent six months discovering the joys of outdoor life: hiking, camping, and trekking. Meeting new people and having new experiences helped form her into an adventurous, self-reliant young woman. She returned, finished college, got into SCUBA diving and boats, and began working on dive and whale watching boats. After working 24/7 with high school students in expeditionary learning projects, Leslie was ready for a change. She was hired as an Able Bodied Seaman working for NOAA. Leslie has been accepted for graduate school and is considering an advanced degree in marine affairs and coastal zone management, but the training opportunities through NOAA are really attractive to her right now. She is enjoying working in the waters of the Pacific Northwest.

Survey Technician Matt Boles (right) locating tide gauge markers on Olga Island.

Umeko Foster is a second-year intern aboard RAINIER from California Maritime Academy. Raised in southern California, Umeko is looking forward to the challenges and opportunities of working aboard ships, either with NOAA or in merchant shipping. She spent this summer and last learning first-hand about living and working aboard an ocean-going vessel. Umeko has worked in a variety of jobs aboard RAINIER. I most often found her standing watch on the bridge, or working on deck duties around the ship. She has worked on the hydrography survey launches, but hasn’t acquired specialized knowledge of the highly technical equipment used in surveying. Her background at the Maritime Academy will qualify her as a 3^rd Mate for work on ships.

Survey Technician Matt Boles comes from Tennessee. With an Associate degree in Geographic Information Systems (GIS) he joined NOAA 18 months ago to gain some practical experience in that field before committing to a 4 year study program. One of the things that influenced his decision was his experience in an internship he did in 2004: the teamwork and positive attitudes of the crew he worked with made him want to become a part of the organization. Matt feels that being in Alaska, far from his family has helped him to become more aware of possibilities and to develop a new set of values about environmental stewardship. His internship aboard the fisheries ship was his first ocean experience and gave him an appreciation for a new part of the world.

TAS Peterson with Lt. Ben Evans atop Olga Island.

He has fine-tuned his goals toward a degree in aerospace science so he will be able to use his skills in remote sensing surveying in other applications such as aerial survey work. He is strongly motivated toward helping people learn more about the world we live in and how to live in it wisely, hopefully avoiding future tragedies like the Exxon Valdez oil spill. Matt, who got married just three months ago, says the hardest parts of his life at sea are being away from family for long periods of time and the lack of physical activity space aboard ships. As a musician (bass guitar player), outdoor enthusiast, and with a strong interest in aviation, Matt likes to spend his free time actively. There isn’t much room to hike on the ship.

AS Leslie Abrahamson splicing lines aboard NOAA ship RAINIER.

Personal Log

I got a really good workout today. I went ashore on Olga Island with Field Operations Officer Ben Evans and Survey Technician Matt Boles. Our job was to locate and document five brass survey monuments for positioning a temporary tide gauge on the Island next season. I served as photographer and we all scrambled around on the rocks looking for the brass plates fixed onto the rocks.

When we finished documenting locations we took a few minutes to climb to the top of the island for the view. ST Boles and I went straight up through the brush at about a 50˚angle and met Lt Evans on top. He had found a better slope and walked right up. There was a pair of Bald Eagles circling and calling above the summit and the view was wonderful. After taking pictures we headed back down. Who would have ever thought I would be climbing like this in rubber boots?

You have to love these “XtraTuf’s!”

May 1, 2006March 18, 2021

Linda Armwood, May 1, 2006

NOAA Teacher at Sea
Linda Armwood
Onboard NOAA Ship Fairweather
April 25 – May 5, 2006

Mission: Hydrographic Survey
Geographical Area: Aleutian Islands, Alaska
Date: May 1, 2006

Weather Data from Bridge
Visibility: 10 nautical miles (nm)
Wind direction: 182°
Wind speed: 14 kt
Sea wave height: 1 ft.
Swell wave direction: 235
Swell wave height: 1
Sea water temp: 7.5
Sea level pressure: 1029.6 mb
Present weather: Partly cloudy
Temperature: °C~ 7.5 dry/6.0 wet

Science and Technology Log

The ship performed a procedure for collecting data from a selected area of the Gulf of Esquibel analogously compared to ‘mowing the lawn.’ In this process the ship actually sails up and down the selected area within the Gulf collecting various data. As the ship sails, parallel lines are produced on the hydrography chart. The hydrography chart is viewed via the DELPHMAP system during this entire process in the pilot’s house and the plotroom. In the plotroom, rotating survey technicians monitor the area being covered with four computer screens and communicate with the pilot’s room when data collection is paused and when it is resumed.

The ship performs this process rather than the launches because the ship works in deeper water than the launches. Sound data was collected today with an instrument called the Seacat. In order to collect sound data with the Seacat the ship has to come to a complete stop. The Seacat is manually attached to cable that is housed with a structure called the ‘J’ frame. The cable travels through two rotating blocks and the Seacast is manually deployed into the water until it reaches the bottom of the water. It is immediately pulled back onto the ship, detached from the cable, and attached to a computer for prompt reading of the data known as a Conductivity, Temperature, and Density (CTD) caste.

Personal Log

Thanks to FAIRWEATHER shipmates for answering all of my questions either verbally, with hand-drawn illustrations, or through demonstrations. The tide staff stop observations that Ensign Gonsalves and I made were consistent with the automatic tide gauge readings. I’ve got the results to prove it!

Question of the Day

Geospatial Semester and Environmental Science Students

Give the length and width of the Gulf of Esquibel. Also, include the name and geographic location of its land boundaries.

Mrs. Armwood

August 31, 2005March 18, 2021

Stephanie Wally, August 31, 2005

NOAA Teacher at Sea
Stephanie Wally
Onboard NOAA Ship Rainier
August 29 – September 10, 2005

Mission: Hydrographic Survey
Geographical Area: Eastern Prince William Sound, Alaska
Date: August 31, 2005

Weather Data from Bridge

Time: 1400
Cloud Cover: Low Clouds
Visibility: 10 nm (nautical miles)
Wind: 340°, 4 knots
Sea Wave Height: 0’
Swell Wave Height: 0’
Sea Water Temperature: 5.0°C
Sea Level Pressure: 1009.2 mb (millibars)
Temp: 11.7°C

Science and Technology Log

The crew of RAINIER has been upbeat since yesterday’s successful installation of a tide gauge on an island close to the face of the Columbia Glacier. Data from the temporary tide gauge will be collected to analyze changes in water level. It is important to know the water level since other portions of the ship’s current mission depend on surveying the bottom in shallow depths.

The officers, surveyors, divers, coxswains, and crew worked together to ensure all aspects of the gauge were installed and operating correctly. The weather proved to be the biggest challenge in the installation procedure. We had periods of heavy rain, stormy seas, and near-freezing temperatures. Thanks to our foul-weather gear, snack supply, alternating breaks, and sheer dedication of the team, we all returned safe and sound to RAINIER. We were welcomed by the CO, XO, and a warm meal from the galley crew.

Today we returned to the island in fairer weather to take bearings of the NOAA bench marks we laid in the rock. By triangulating the position of each disc, their location can be recorded for future surveying and exploration. Even though Global Positioning System (GPS) technology provides the station location, it is important to have a back up means of finding these bench marks in the future. Who will look after our tidal gauge and bench marks while we continue our transit toward Valdez? Hopefully the harbor seals, otters, and bald eagles!

Answer to yesterday’s question: 180° = South

Mission: Hydrographic Survey Geographical Area: Alaskan Coastline, the Inside Passage Date: Wednesday, September 21, 2011

Weather Data From The Bridge

Science and Technology Log

Mission: Hydrographic Survey
Geographical Area: Alaskan Coastline, the Inside Passage
Date: Wednesday, September 21, 2011