Barney Peterson – Page 2 – NOAA Teacher at Sea Blog

August 19, 2006March 26, 2021

Barney Peterson, August 19, 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 19, 2006

Weather Data from Bridge
Visibility: 8 n.m.
Wind direction: 240° C
Wind speed: 8 knts
Seawater temperature: 10° C
Sea level pressure: 1012.3 mb
Cloud cover: Cloudy

Science and Technology Log

Friday I got to spend time on the bridge while the ship was moved from one anchorage to another less than a mile away. The reason for the move was to anchor in a more protected spot as the forecast is for higher seas and stronger winds. When weather readings are taken and data is sent, the ship also receives a forecast to help the captain plan for the safety of his vessel and crew. To know where to anchor the captain must understanding the geology and topography of the islands where we are working as well as knowing about the surface of the earth under the water.

Our first anchorage was chosen because the water was moderately deep and there was room for the ship to turn on the anchor chain as the wind and tides moved us. The second anchorage was chosen because the prediction was for winds from the southwest. We moved deeper into a bay surrounded by mountains between one and two thousand feet tall. There was protection from the predicted winds and room for the ship to maneuver.

This diagram show the cone-shaped pattern that the chain will move in as the ship swings around at anchor. — The cone-shaped pattern that the chain will move in as the ship swings around at anchor.

We weighed anchor from our first anchorage. LT Evans took down the flags and the anchor ball (showing the anchor is down) was lowered. With one man working the winch and another carefully watching the anchor chain, the raising process was begun on a command from the bridge. Ensigns McGovern and Greenway were on duty along with Able Seaman Leslie Abramson. Captain Noll was there to observe and I was invited up to watch by Executive Officer Julia Neander. The anchor was raised slowly and the chain fed into a locker under the deck in the bow of the ship. We gathered speed and moved to our new anchorage with Ensigns McGovern and Greenway using the ship’s radar to move us according to a predetermined route.

As we approached the new spot, the speed was cut, and finally the engines were reversed to stop us in just the right place. While we were moving all personnel on the bridge watched attentively, sometimes with binoculars, for any indications of problems. There was a large kelp bed to the starboard side of the anchorage, an indication of shallow water and rocks on the bottom. This was something we needed to miss.

Finally the command was given to drop the anchor. Ensign McGovern ordered that they release five “shots” of chain, thinking that this would reach bottom if the depth in this area was what they thought it would be. The survey boats had not covered this area, so charts did not show depths. A shot of chain is equal to 90 feet. At five shots the anchor had not yet settled on the bottom so McGovern ordered an additional five shots. When eleven shots were out, we began moving the ship slowly with the engines to try and set the anchor. This would be apparent when the bow observer could see heavy tension on the chain and those aboard the ship should have felt a slight tug….we didn’t.

After trying several time, the captain determined that the anchor was not on a good surface and was dragging. This could be very dangerous if the wind rose as predicted because the bay we are in is fairly narrow and there would not have been much time to take action to keep the ship a safe distance from the shoreline. The order was given to raise the anchor again.

As the chain came up we could smell the foul mud from the bottom. Bits of mud and slime were caught in the links and had to be washed off with a hose and nozzle so the chain locker wouldn’t be dirty and smell awful. The captain brought me a sample of the stuff…heavy gray-green-black clay with bits of shell and plants in it. (The smell reminded me of pulling my boots out of the middle of a swamp…rotting stuff! I was happy to toss the mud overboard and wash off my hands.)

The captain picked another spot a few ship-lengths from this one and the ship was moved slowly. Then anchor was lowered again with more than eleven shots of chain being released before the anchor settled on the bottom. This time, as we gently powered up the engines the man on the bow called out “Light tension….Medium….Heavy and holding.” At that point even I felt the slight dip that signaled that the anchor had set.

There is always someone on the bridge on watch, 24 hours a day. If the anchor were to drag tonight, the watch would call the captain, waking him if necessary. They would make a decision about what to do to keep the ship and crew safe.

Of course, once the anchor was down, the person in charge on the bridge had to calculate the distance the ship would move as it swung on the anchor with a chain eleven shots long. There is a chart for this. The pattern is an inverted cone with the anchor being at the point and the bow of the ship at the circumference of the base of the cone. (In real life the chain droops a bit from its own weight so the lines aren’t totally straight.) It is important to calculate this carefully and to know that the water all the way around the cone is deep enough that the ship can swing without danger of striking any underwater objects such as rocks or sunken ships.

Question of the day: If the anchor chain is eleven shots long, how far is the ship above the ocean floor when the chain is extended straight up?

August 18, 2006March 26, 2021

Barney Peterson, August 18, 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 18, 2006

wet and dry bulb thermometer — Wet and dry bulb thermometer

Weather Data from Bridge
Visibility: 10 nm
Wind direction: 220˚
Wind speed: light 0 – 2 knots
Sea wave height: 0 – 1’
Seawater temperature: 9.4 ˚C
Sea level pressure: 1017 mb
Cloud cover: cloudy (8/8)

Science and Technology Log

Wednesday I spent time on the bridge, observing what happens when the ship is traveling at sea. My classes at James Monroe Elementary have participated in the GLOBE program, acquiring and sending weather data daily to be used to form a picture of conditions around the world. It was particularly interesting to me to learn that the crew of NOAA ships take much the same readings hourly and report them every 4 – 6 hours to the National Weather Service to help develop the predictions that help us all guide our day to day lives. I was especially impressed that the readings I saw were made using traditional instruments, not an automated electronic weather device.

One of the people in the pilot house logs weather every hour on the hour. There is an outside station on the starboard wall of the pilot house. This gives a temperature reading and allows them to calculate relative humidity. That is the difference between how much moisture is in the air, and how much total moisture the air is capable of holding. It may be expressed as a percentage, or decimal number. For hourly reporting, the relative humidity is not recorded and it is calculated automatically by when the “Big Weather” is submitted to National Weather Service. Both temperature of the air and sea water are read in ˚Fahrenheit and converted to ˚Celsius for reporting.

Wind speed is read from an anemometer mounted on the ship’s mast. This reading is a bit trickier if we are under way. When the ship is moving, the ship’s speed is subtracted from the anemometer reading to give a corrected wind speed. (Otherwise, the reading is like what you would get running while holding a pinwheel in front of you…much faster air movement than what is actually happening.) There is a wind vane mounted on the front of the ship and also an electronic gauge for reading wind direction.

The barometer (at left) is used for reading air pressure. It is located on the back wall of the pilot house and always gets a gentle tap before a reading is taken. This measurement is important because trends up or down in air pressure give clues to developing weather systems. The pressure is recorded in milibars. The ship’s barometer is shown at left. Some measurements involve using experience and personal judgment as well as instruments. These are the ones for wave height, swell height, cloud cover amount, cloud height, and visibility. The accuracy of these readings depends upon the experience and care of the person making them. The sea wave and swell can be estimated by careful observation, which seems to become second nature to the crew because they are exposed to them all the time. They are recorded in feet. The direction of the swell is always shown as the direction in which the swell is going. It can be measured using a device mounted on the deck outside the pilot house.

Cloud cover is measured in eighths. The observer divides the sky, calculates by observation how many eighths of the sky are covered by clouds, and reports that fraction. Likewise, a person must be a careful observer to note the kind of clouds they are seeing and where they mostly appear in the sky. There is a cloud chart available that shows pictures of cloud types and tells the altitudes at which they are commonly formed. This is a great help. (The cloud chart is shown at the right.) When there are low clouds, and there is land nearby, the observer can check the elevation of a point of land and judge the elevation of the lowest clouds as they appear against that point. Another measurement that may sometimes have to be an experienced estimate is visibility. Again, if land is visible, the observer tells how far away she/he can clearly see according to landmarks and the distances on charts or the ship’s radar screens. It is a lot harder to make this judgment when the ship is at sea, with no landmarks to help. That is when experience is especially important. One aid in this case is that the known distance to the horizon, due to the curvature of the earth, is eight nautical miles. That means that if the observer can see clear to the horizon, visibility is at least 8nm.

This day I watched Able Bodied Seaman (AB) Jodi Edmond take weather readings and report “Big Weather” to the National Weather Service using the internet.

A cloud chart on the NOAA’s National Weather Service Web site.

Personal Log

I am running about a day behind writing and submitting my logs. There is so much to do and see that I forget to spend enough time writing. I am using the personal journals that my students gave me at the end of the school year to record my impressions and thoughts every evening. Those act as memory-joggers when I sit down at the computer to do my formal writing.

Everyone aboard the RAINIER is very friendly and helpful. I am still making a few wrongs turns or selecting the wrong stairs to get to where I need to go. The officers and crew are great about pointing me in the right direction and giving me clues to help me remember how to find where I need to be when.

Every afternoon the orders for the next day are posted in several spots throughout the ship. These list the survey boats that will be going out, and their crews and assignments. The list also tells about responsibilities on board ship…both for the officers and the crew. These are called the Plan of the Day (POD) and are important for everyone to read when they are posted.

Question of the Day

How is wind direction normally reported: do we tell the direction from which the wind comes, or the direction toward which it is blowing?

August 16, 2006March 26, 2021

Barney Peterson, August 16, 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 16, 2006

Weather Data from Bridge
Visibility: 12 nautical miles (nm)
Wind direction: 234˚
Wind speed: 0 – 3 knots
Sea wave height: 1’
Seawater temperature: 11.7˚C
Sea level pressure: 1011.8 mb
Cloud cover: 8/8 Height: 2000 -3000’ Type: Stratus

My first view of the NOAA ship RAINIER at the dock in Seward, AK.

Science and Technology Log

Yesterday I spent time in the Plot Room learning about the technology used to survey the surface of the earth underneath the ocean (bathymetry). For each survey the computers must have accurate, real-time information about the behavior of the ship on the sea surface (pitch, roll, speed) because all of this can affect the accuracy of sonar readings. The sonar (sound waves) is beamed from the bottom of the survey vessel and spreads out in a cone shape to the undersea surface. Bottom features that stick up closer to the sea surface reflect sonar waves and return echoes sooner so they show up as more shallow spots. Echoes from deeper places take longer to return, showing that the bottom is farther away at those places.

The data from each day’s survey is downloaded into computers in the Plot Room. Survey technicians review the data line by line to be sure it all fits together and to “clean up” any information that is questionable. They use information about the temperature and conductivity of the water where the survey was taken to understand how fast the sonar waves should be expected to travel. (This information is critical for accuracy and is collected every 4 to 6 hours by a device called the CTD. The CTD is lowered from the ship and takes readings at specified depths on its way down through the water.)

Ensign Megan McGovern and crew partner in full firefighting bunker gear for our first Fire/Emergency Drill.

When survey work is in deep water, it is done from the ship using equipment that can cover a wider area in less detail. The launches are used for shallow water work where it is more important to navigation to have finer detail information on water depths and underwater features of the earth surface. Bonnie Johnston, a survey technician, spent about an hour explaining how the system works and showing me how they clean up data before it is sent off for the next stage of review, on its way to becoming part of a navigational chart. Computers used have two screens so survey technicians can see a whole survey line of data and look closely at information on tiny spots at the same time without losing their place on the big screen. This helps to judge whether changes of depth are accurate according to trends on the sea bottom, or spikes that show an error in the echoes received by the sonar. The software also allows them to see data as 2-D, 3-D, color models, and to layer information to give more complete pictures.

Tomorrow we are scheduled to begin our actual survey work in the Shumagin Islands. In between making new surveys the technicians are kept very busy working with the data they have on hand. There are many steps to go through to insure accuracy before data is ready to use for charts.

This is the 4.5 foot dogfish shark caught by a crewmember. This shark has no teeth even though it looked ferocious. released it after taking pictures.

Personal Log

My first two days aboard the RAINIER have been a swirl of new faces and places. The only name I knew for sure before I arrived was Lt. Ben Evans who had exchanged email with me about the gear I would need. I was met at the Seward RR station by and welcomed onto the ship by Ensign Megan McGovern. She gave me a quick tour of the ship, including where to put my gear. I felt like a mouse in a maze: up and down steps, around blind corners, and through doorways. It has been much easier so far to find my way than I thought it would be. Reading books that use nautical terms has helped give me a background to understand port, starboard, fore, aft, head, galley, bridge, fantail, and flying bridge. Now I just need to remember where they all are.

Monday was taken up with a safety briefing, checking out equipment such as my flotation coat, personal flotation device (life jacket) for use in survey boats, hard hat, and immersion suit. I spent several hours reading Standing Orders that all persons aboard must read before being allowed to stay. I talked with the medical officer, and discovered where to eat and the times meals are served. Tuesday we had a Fire/Emergency Drill at about 1030 (10:30 am) for which I reported as fast as I could to my assigned station on the fantail. We were checked off on a list and some crew members practiced with fire fighting equipment.

Just as we finished that drill, the Executive Officer called an Abandon Ship Drill. Everyone rushed to quarters to get immersion suits, hats and any assigned emergency gear before reporting to muster stations. Again we were checked off and all accounted for before anyone could return to what they were doing before. These drills are an important part of shipboard life. They are required once a week and always within 24 hours of the ship sailing from port.

I am sleeping and eating well. The food is like camp and so are the bunk beds. So far I have seen lots of salmon: the stream in Seward was full of migrating Coho (silvers); the sea at Twin Bays was alive with jumping Pinks. Monday night one crew member, fishing from the fantail while we were anchored, caught and released a 4.5’ dogfish (shark). The next day someone caught an 8 lb. silver. There are sea lions, otters, gulls, eagles, puffins and dolphins to watch. I hate to close my eyes to sleep because I know I will miss seeing something wonderful.

Question of the Day

What is the speed of sound through air? Does sound travel faster or slower through water?