26 January, 1998
Hello Everyone! We still are in the Cape Adare area, gathering information about the last ice age by looking at the clues the ice sheet left behind on the sea floor. The Nathaniel B. Palmer is at: 70 degrees 56 minutes south latitude 169 degrees 53 minutes east longitude Yesterday I spent some time on the Bridge. This is the place on the ship where they steer the boat. It is up high and surrounded by windows. Why do you think that is? I spoke with Mr. Lee Crowe, Chief Officer of the Nathaniel B. Palmer. He has been working on the Palmer for 3 years. When he is not on the ship, Mr. Crowe is at home with his family in Mississippi. He has a daughter named Sarah who is 12 and a son named Josh who is 9. Mr. Crowe is here to steer the ship, assist the Captain and act as the Captain when needed, and oversee the ship operation and safety training of the crew. It is a job that takes many hours each day! Mr. Crowe told me about the ice breaking capabilities of the Research Vessel Nathaniel B. Palmer. She is an ice breaker with very powerful engines and a special hull (body). The hull is a double hull so that it is extra strong and can push through ice without being damaged. The engines are not as powerful as some of the ships designed especially to escort other ships through the ice or break the ice channel into McMurdo Station each spring. The Palmer's engines are designed to move through about three feet of ice. The Palmer is made to allow us to work safely in ice. We actually try to avoid thick ice because it is not as efficient to go through - the ship uses more fuel when the breaking ice. Before you can break through ice, you have to know something about it - you do not want the ship to get stuck! Some Antarctic explorers have gotten their ships stuck in the ice. My family named me for Ernest Shackleton. Mr. Shackleton went to Antarctica to find a place where he could lead an expedition across the continent from Weddell Sea to Ross Sea. His ship, Endurance, became trapped by sea ice in Weddell Sea for more than 11 months. The ship eventually was crushed, but the crew made it to safety after staying almost a year and a half in Antarctica. Knowing how ice forms and behaves is a good idea and will help us to avoid getting trapped or damaging the ship. We have an advantage over the early explorers, however - we get satellite weather reports and sea ice images so we can plan our path. Sea ice forms each year around Antarctica. It starts when the air temperatures fall and the surface ocean temperatures cool in the fall. Tiny ice crystals form; these are called frazzle ice. The ice crystals start joining together, and a thin film of ice forms on the water surface. The ice is called grease ice because the water looks like it has a layer of grease on it. Eventually the ice plates grow larger and larger, forming plates that look like lily pads. The plates have upturned edges because the plates bump into each other. This is called pancake ice. Pieces of pancake ice can get up to 20 feet across! Water freezing onto the bottom and snow falling onto the top help pancake ice to thicken. Pieces of pancake ice sometimes get pushed up onto each other (rafting), making the ice even thicker. Eventually the pancakes join and a thin sheet of ice forms around Antarctica. This blanket of ice doubles the size of Antarctica each year! With warmer temperatures the sea ice melts back each spring. Just think about all the animals in Antarctica. They get their food from the sea. What do you think the animals do as the ice changes size through the year? The pancake ice is also called pack ice. The ice pack can be very close together and difficult to get through, or it can be pieces with lots of water between. Sometimes the ice stays for more than a year - this is called multi-year ice. It is harder than sea ice because the ice has very little salt in it - the salt has slowly separated out from the ice (remember your experiment making sea ice a few weeks ago?). Ice that is attached to the coast line is called fast ice - it is "held fast." Fast ice often is older than a year and is very hard and thicker than the annual sea ice. The ship is designed to go through most annual sea ice in Antarctica - it is usually less than 3 feet thick. When it moves through pack ice with a lot of water between the pieces, it pushes them out of the way. When the ship gets to pack ice that does not have spaces between it or to thicker, harder fast ice, the ice has no where to go, except under the boat - it makes a lot of noise - like someone banging on water pipes with a hammer! To break through the ice the ship "runs forward" so that its nose is on the ice - the weight of the boat breaks the ice. Then the ship backs up and the powerful engines push it forward again, onto the next piece of ice. Progress is slow! Once when trying to deliver supplies to a Russian research station, Mr. Crowe spent 4 hours getting the ship a mile and a half closer to the station! Mr. Crowe says that he misses his family when he is away, but he enjoys working in Antarctica because driving a ship in Antarctica is challenging - the environment makes him use all his boat-handling skills. His favorite part of the job is working with the scientists collecting new information about how our Earth works. As he says "if you've got to work somewhere - Antarctica IS the place to be!" More soon from the ice - E. Shackleton Bear P.S. If you want to see some pictures from our cruise, look at Kim Giesting's journal at this same website - I have sent some there!Return to E. Shackleton Bear's Page
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