Joan Raybourn, August 24, 2005

NOAA Teacher at Sea
Joan Raybourn
Onboard NOAA Ship Albatross IV
August 14 – 25, 2005

Mission: Ecosystem Productivity Survey
Geographical Area: Northeast U.S.
Date: August 24, 2005

Weather Data from the Bridge

Latitude: 43°32’ N
Longitude: 69°55 W
Visibility: 8 miles
Air Temperature: 17° C
Wind direction: E (99 degrees)
Wind speed: 5 knots
Sea wave height: 1’
Sea swell height: <1’
Sea water temperature: 18.8°C
Sea level pressure: 1018.0 millibars
Cloud cover: 7/8 Cumulus

Question of the Day: At what degrees on the compass would you find the intermediate directions? (Use information below to help you and look for the answer at the end of today’s log.

Yesterday’s Answer: GMT stands for “Greenwich Mean Time”. GMT is the time at the Prime Meridian, which passes through Greenwich, England. People around the world can use this time as an international reference point for local time. We are on Eastern Daylight Time (EDT), which is four hours behind GMT. At 1:33 a.m. GMT, it was already August 24 in Greenwich, but our local time was 9:33 p.m. EDT, still August 23, so that is the date I used in the log.


Science and Technology Log

Over the last eleven days, the ALBATROSS IV has zigzagged back and forth across southern New England waters, Georges Bank, and the Gulf of Maine. The collection stations were chosen in advance of the trip and plotted on an electronic chart. So how does the crew drive the boat to the next station?

Ship navigation is a combination of automated and manual tasks. Based on the ship’s current position and the latitude and longitude of the next station, the navigator determines what heading to take. That is, he decides in exactly which direction to go using a compass. The ship has an electronic gyroscope as well as a manual compass similar to the ones you may have seen, only larger. It has a magnetic needle that points north, and is divided into 360 degrees. The cardinal directions are these: 0° is north, 90° is east, 180° is south, and 270° is west. The navigator enters the heading into the ship’s navigation computer, and if conditions are normal, he can set the ship on Autopilot. Then the computer will automatically adjust the ship’s direction to keep it on course.

The fact that the ship is running on Autopilot does not mean that the crew can take a break. The crew sets the ship’s speed depending on weather and sea conditions, and on how much other ship traffic there is in the area. In open water, the ALBATROSS IV cruises at about ten to twelve knots, which means we cover about 10 to 12 nautical miles per hour. The crew must constantly monitor to make sure the ship is operating safely and efficiently. They plot the ship’s course on paper, monitor weather conditions, watch for other ships and communicate with them, and adjust the ship’s course and speed. At the collection stations, they are able to put the ship at the exact latitude and longitude called for, and keep it there during water casts and sediment grabs, or moving at just the right speed for plankton tows.

Navigators keep a constant watch out for other ships, using a combination of visual and radar data. They use radar to pinpoint the ships’ locations, and often can be seen scanning the sea with binoculars. Signal lights on ships help with navigation, too. Ships have a red light on the port (left) side and a green light on the starboard (right) side. This helps navigators know which side of a ship is facing them and in which direction it is headed. Of course, radio communication makes it possible for ships’ crews to talk to each other and make sure they are passing safely.

Personal Log

Tonight will be the last night of the cruise. We expect to be back in Woods Hole by midday tomorrow, two days earlier than planned. We’ve been blessed with excellent weather, and have made good time cruising between stations. I was very excited last night to see fireworks in the toilet! Toilets on the ship are flushed with sea water, which often contains some bioluminescent phytoplankton. Sometimes the swirling action of the water will excite them, and we’ll see blue-green sparkles and flashes as the water washes down. (Sewage and waste water are biologically treated on board so that they are safe to release into the ocean.)

I want to thank the crew of the ship, especially the NOAA Corps officers who have welcomed me on the bridge and answered many questions about ship operations. I am particularly grateful to Capt. Jim Illg, who reviewed all of my logs, and Ensign Patrick Murphy, who answered many questions about weather and navigation.

Finally, I want to thank the scientists who willingly shared their knowledge and patiently taught me protocols for their work. Jerry Prezioso, a NOAA oceanographer, served as chief scientist on this cruise. He helped me prepare ahead of time via telephone and email, and has been endlessly helpful to this novice seafarer. His enthusiasm is infectious, and he has a knack for turning any event into a positive experience. Jackie Anderson, a NOAA marine taxonomist, taught me to operate the CTD unit and helped me identify the kinds of zooplankton we captured in the bongo nets. Don Cobb, an EPA marine environmental scientist, helped me understand the kinds of research the EPA is doing to monitor the health of our oceans and estuaries. Thanks to all of them for their  work in keeping Planet Earth healthy, and for making this an experience I can take back to my classroom and use to help make science real for my students.

Today’s Answer: The intermediate directions are those that fall between the cardinal directions, so to find their degree equivalents, find the halfway point between the numbers for each cardinal direction. Northeast would be at 45°, southeast would be at 135°, southwest would be at 225°, and northwest would be at 315°.