NOAA Teacher at Sea
Aboard NOAA Ship Rainier
May 6-16, 2013
Mission: Hydrographic surveys between Ketchikan and Petersburg, Alaska
Date: May 10, 2013
Weather on board. Taken at 1600 (4:00 in the afternoon)
Latitude: 55° 47.29’ N; Longitude 130° 58.27’ W
Broken skies with a visibility of 10+ nautical miles
Wind from the west at 15 knots
Air temperature 12.6° C
Sea temperature 8.9° C
Science and Technology Log: The Small Boats
Yesterday the ship captured most of the ocean basin using its multibeam sonar equipment located on the bottom of the ship. Today we set out in smaller launches that could take us to the sections of the ocean the big ship couldn’t. Three teams were deployed, each containing a coxswain (person who has the skills to handle the boat), senior hydrology technician (in charge of the survey work to be done), and several others to help – one boat of which was gracious enough to take along a rookie “Teacher of the Sea” to experience first hand the work involved.
We all met on the fantail (rear deck) of the ship at 6:30 AM to go over the work that lays ahead. From there the launches were lowered off the ship, we entered, were released, and off we went. While still in the early morning low tide we examined the shoreline to verify the existence or non-existence of rocks in question from the last survey. We conducted our surveys throughout the rest of the day in areas not able to be accessed by the larger ship. Each launch is also equipped with multibeam sonar units on the bottom of the boat (image) and a plotting computer on board. As with the ship, the computer measures and controls for location (GPS); heave, pitch, and roll; and the temperature and salinity of the water column below our boat.
The work is similar, yet has a different feel. Unlike the automated features on the ship, a control panel allows the surveyor to hand tune variables that will help assure the best measurements. We can control the strength of the sound waves leaving the boat, the frequency of pings, wave length, and the degree of sweep that will be collected. Doing so allows us to maintain sufficient strength to capture tbe bottom, but not so overpowering that we lose the finer details such as the makeup of the bottom. Each boat sets a path back and forth at a speed of 7-10 knots in the sections assigned by the FOO (Field Operations Officer). This is repeated until each section is covered. This takes a concerted and collaborative effort between the coxswain and technicians. When surveying from the ship, the Moving Vessel Profiler’s fish can be cast by the push of a button at the computer in the Plotting lab. Not so on the launch. After bringing the boat to a stop, we lift over the CTD (conductivity, temperature, depth) instrument. We allow it to drop to the bottom before we turn on the winch to reel it back in. It is lifted out and attached to a cable connected to the computer where the data is downloaded.
Before we get back to the ship, we download the day’s data to an external hard drive and hand it off to another crew that begins the job of cleaning the data to be pieced together with all the other sections of data. We end with one complete picture of the project area.
Life at sea
There are 46 people living and working on board the ship. The launches go out with a smaller group of 4. Spending all day on a small boat with three other people necessitates attention to clear communication channels. The waves continually keep the boat in motion providing a challenge to manipulate the mouse and detail on the computer screen. In between there are many moments of quiet allowing for conversation and banter. It is in those moments you get to know one another better and forge strong relationships. This close community is evident among the crew on board. Such is the allure of sea life.
In anticipation of a trip to SE Alaska, I did a bit of research on what kind of weather to expect. Ketchikan is in a rain forest and noted for being the rainiest city in the United States with an average rainfall of 160 inches a year. Since my arrival, I have enjoyed sunshine and calm seas. People have assured me how unusual this is and to expect a change. The forecast for tomorrow suggest the change will arrive. Seems to experience life at sea without a bout of inclement weather would not allow full appreciation of the grandeur we have had. I will take them both expecting there will be equal beauty in the rain and clouds.