NOAA Teacher at Sea Donna Knutson
NOAA Ship Oscar Elton Sette
September 1 – September 29, 2010
Mission: Hawaiian Islands Cetacean and Ecosystem Assessment Survey
Geograpical Area: Hawaii
Date: September 24, 2010
I Hear Them!
Mission and Geographical Area:
The Oscar Elton Sette is on a mission called HICEAS, which stands for Hawaiian Islands Cetacean and Ecosystem Assessment Survey. This cruise will try to locate all marine mammals in the Exclusive Economic Zone called the “EEZ” of Hawaiian waters. The expedition will cover the waters out to 200 nautical miles of the Hawaiian Islands.
At the beginning of the cruise the acousticians were gifted with a brand new array! An array is a long clear soft plastic tube containing all the electronic equipment needed to absorb and transmit sound to the sound equipment back in the ships lab. The array had (notice I said had – past tense) hydrophones and transmitting boards throughout its 50 foot length. In order for the sound to travel through the water and be received by the array, the entire electronic circuitry inside the array needed to be immersed in a liquid similar to salt water’s density. If the electronics were exposed to sea water there would be too much corrosion for the system to work properly. So, they chose a colorless oil to fill the array. The array is laid out on the fantail (back deck) bridge and is connected to a spool of power and relay cords (ok, you realize by now I know virtually nothing about electronics) and then the cords are slipped into the lab and connected to the sound equipment. I know that last part for certain, because I helped Nicky wire tie them together at the beginning of the cruise.
When the array was (yes, still past tense) lowered into the water behind the ship, it was 300 m back and 6 m deep. It needed to get a long way past the boat, so the boatnoise wasn’t the only thing heard. Unfortunately the acousticians could not pick up the normal ocean sounds and animal clicks that they have become accostumed to on past cruises.They looked at the inside equipment, took out boards, tested solders, and electrical power strips. They checked out the transmitters, connections and screws. (They reminded me of the Grinch not overlooking one last detail!) Still the blasted thing did not work. I hate to admit that I shyed away from them for a time, because all the help I could provide would be in giving inspirational clichés, and I know they had enough of those already. Eventually, enough was enough and even though, and yes remarkably so, they were in good spirits, time had come to take the array apart. Erin was there to assist, and Kim the Sette’s electronic technician was working side by side with Sussanah, Nicky and Yvonne. They gutted the whole thing, oil and all. Then they checked the mini-microphones and relay boards. I was very impressed!
All was done that could be so it was decided to put it back together, and try it again. It worked! I wasn’t surprised but rather amazed! Unfortunately two of the four hydrophones stopped working. Each hydrophone picks up different frequencies so if they don’t all work. The array doesn’t work. Drat! Not to be overcome with minor setbacks. (Minor to them, I’m thinking definitely Major if I had to work on it!) The acousticians set to work making an entirely new array! One day I decided to stop down in the lab to check things out and see what new adventures they were presented with. As Sussanah sat and stripped wires, I asked Yvonne and Sussanah how much electronic background they had to have for this job because I was clearly impressed. Neither of them has had any classes, only the experience of working on similar equipment in the past.
None of them had an electronic background, but they decided to make a new array themselves with the left-over parts. They were determined to become an active part of the survey team! And they did it! They built their own array! It was (yes drat, past tense again!) working great until one day it was getting progressively worse. When the girls pulled it in, they noticed it had been bitten! Some fish came up behind it and bit the newly fabricated array! What kind of luck was that! Salt water was leaking in. “How can you fix that?” I asked Sussanah at dinner. She said, with her British accent, (which is so much fun to listen to, and one of the reasons I like to ask her questions) the kevalar material inside the device, which is giving the new array strength and structure, is acting like a wick and soaking up the salt water. So they split the kevalar and it is being held together with a metal s-connector to try and stop the wicking.
It will hold for the next six days until we can get back to port. Wow, for all the adventures/troubles they are picking up some good information! The array will receive the sounds from the “toothed whales” but to pick-up the lower frequencies from the baleen whales, the acousticians send out a sonobuoy. A sonobuoy is an independent device that is dropped over board, and floats on the surface while sending the signals back to the ship. As I am writing this I am told the acousticians are hearing pilot whales! They can not only hear them, but can also tell where the whales are at! I need to go check it out! They are truly an amazing group of young women. Even though I have known them for only for a short time, I am truly proud. Their hard work has definitely paid off. Their determination is to be admired