NOAA Teacher at Sea
Rita Salisbury
Aboard NOAA Ship Oscar Elton Sette
April 14–29, 2013
Mission: Hawaii Bottomfish Survey
Geographical Area of Cruise: Hawaiian Islands
Date: April 19 2013
Weather Data from the Bridge
Partly cloudy, winds ENE 10-15 knots, sunrise 603, sunset 1846
77 degrees F (25 degrees C)
Humidity 85%
Barometer 30.09” (1019.5 mb)
Dewpoint 72 degrees F (22 degrees C)
Heat Indes 78 degrees F (26 degrees C)
Visibility 10 miles
Science and Technology Log
We have been calibrating the acoustic equipment for a few days in order to be ready for our survey of bottomfish. It was a long process, but necessary. Four of us worked on moving a small titanium sphere under the boat by maneuvering it to different positions. A scientist working in the e-lab (electronics lab) used different frequencies from the transducers to locate the sphere and record the results. Graduate students and NOAA scientists worked until 1:00 in the morning to get the job done.
While we were working on the acoustics, other scientists were working on a test run of the ROV. The currents were very strong when they deployed the ROV but it performed well and was successfully retrieved. Operating it is a lot like the controls to a video game, only the stakes are much higher.
The AUV was deployed on Wednesday. The first step was to do a rehearsal of the procedures for deploying and retrieving the AUV. Everyone had a job to do and it was made clear who would be doing what and when. While it was obvious that certain people were in charge, they asked that if anyone thought they had a better idea of how to do something, or had a question, to speak up. At one point, the captain, CO Koes, asked everyone who was not actually part of the procedure to move to one of the side of the deck so she could see who was actually supposed to be working.
After the walk-through rehearsal, the AUV was lifted off the deck by a large crane and placed into the water off the fantail of the ship. At first it was tethered to the ship, but after awhile it was released and became independent of the ship. The scientists want to be as sure as they can be that the AUV will operate properly before letting it go so they run through a checklist. If everything is working correctly, they release the AUV.
The AUV is pre-programmed for the mission so it is important to know about the underwater geography of an area. The AUV needs to be within 30 to 35 meters of the ocean floor in order to know where it is. Other than that, it follows the pattern that the scientists created. If the AUV doesn’t return to the ship, it’s a big deal. It’s very expensive and difficult to replace. The scientists designed it with that thought in mind.
In addition to the high-tech solutions programmed into the AUV, the scientists also included low-tech ideas into the equipment to retrieve the AUV in case something goes wrong and the AUV is submerged and unretrievable. There is a “drop weight” attached to a strand of zinc. Zinc corrodes quickly in salt water. Through testing the scientists have already determined how thick the zinc strand should be in order to corrode through in a given amount of time at a particular water temperature. The strand that they are using on this cruise is constructed to corrode through in 5 1/2 hours. Once it corrodes, the weight drops off and the AUV rises to the top of the water where it can be seen and picked up. The zinc strand is replaced and another weight is attached. All the weights are the same size and weight so they are interchangeable. Otherwise, the scientists would have to recalibrate the AUV every time they changed weights. I was really impressed to see that the scientists use a combination of high and low tech to make their AUV successful.
The scientists on the Oscar Elton Sette use some smaller boats to assist with their research. One thing that I do to help out is make bait for the small boats to use to attract fish. We take frozen squid and sardines out of the freezer a few hours before we need them and put them on a protected place on the deck. After they thaw, we put them in a commercial quality food processor and grind them up into marble-sized chunk. Then we put the chunky bait into plastic bags, seal them, and put them back in the freezer until they can be delivered to the boats that need them.
Personal Log
This ship is amazing! It’s big and packed with the scientific equipment. The “wet lab” has become the acoustics lab for this trip and the e-lab is above that. The mess is open 24 hours for snacks, (as long as you clean up after yourself), and serves three meals a day. The cooks are really talented and are always providing fresh new ways of serving something. Fortunately, there’s a gym a couple of decks beneath mine!
There’s a movie room, a laundry, a tv room with books and computers, and a ship’s store. There’s even a full-time medical officer on board. My stateroom is set up well. There are 6 spacious bunks, drawers under the bottom ones and lockers for everyone, built-in desks with ethernet access, and a large bathroom. Since everyone is on a slightly different schedule we do our best to be quiet and to keep the lights low.
On Tuesday, we had emergency drills. Everyone has a specific place that have to go to when the alarms sound. If it’s a fire alarm or a man-overboard drill, I have to go to the Texas Deck. If it’s an abandon ship drill, I go to the boat deck and put on my orange gumby suit. That was a little tricky and very hot, but I’m glad they let us practice it.
One thing I’ve noticed on the ship is how everyone has a job to do, but they are always ready to pitch in and help someone else. Meals are really interesting. The mess is small and has several tables set up with 4 chairs at each table. People sit with different people all the time. It doesn’t seem to matter who is an officer, a crew member, or a scientist. Everyone sits with everyone else.
The captain gave me a tour of the bridge on Tuesday. It was late and we ran out of time, so she has invited me to come back up and finish the tour
soon. I was impressed by the number of back-up plans in place. There didn’t seem to be one piece of equipment that didn’t have another piece doing the same job in a slightly different way. This allows the ship to continue working properly on the chance that something stops working. The bridge is the control center of the ship and has alarms and notifications for anything that might crop up–low fresh water levels, smoke, fire, and anything else you can think of.
Did You Know?
Sound is vibration transmitted through a solid, liquid, or gas. The speed of the vibrations, or how quickly they cycle, determines the frequency. Frequency is measured in cycles per second, or hertz (Hz). Humans can hear certain frequencies, while bats and dogs can hear others. Whales and dolphins hear even more frequencies.
The sound waves we are using on the Oscar Elton Sette will bounce off the fish and reflect back to the ship, allowing the scientists to locate the fish and determine their shape, size, and movement.
Animals I Have Seen
Seen off the coasts of Maui, Molokai, and Lanai:
Needlefish
I thought they were barracuda at first, but someone explained the difference to me
Humpback Whales
Dolphins–too far away to identify the species