Throughout this expedition, the Oden has encountered ice that she needed to break through, and watching this process has been fascinating. The Oden is unique among icebreakers because she does not "break through" the ice with a reinforced pointed hull. Instead, she rides UP on the ice with her flat, rounded bow and crushes the ice underneath. She has a special "flushing" system which sprays water, warmed by the engines, in front of the bow, lubricating the ice for easier movement over it. She also has a "heeling" system, which is comprised of two large tanks in the bow, connected by a huge pipe and pumps which quickly transfer water from the port (left) tank to the starboard (right) tank. This allows the Oden to intentionally "rock" from side to side to better crush the ice. In fact, she can almost "climb" up on the ice using this system!
In areas where the smaller ice floes were widely spread out, the Oden just pushed ahead, the floes moving to either side as the ship passed by. As the ice floes increased in size, the ship would hit the ice and we would watch as a cracks opened up in the ice, first narrow, then widening and widening until the floes broke into smaller pieces and passed by.
The Oden approaches a large ice floe.
The floe cracks as the Oden moves into it.
Some ice chunks would be pushed under the Oden, only to emerge on the side of the ship, popping up like a cork. When the ice pieces turned over, we could see the brownish colored algae that was growing underneath.
As the ice blocks overturn, you can see algae growing on the underside of the meter thick pieces.
Occasionally, the Oden would encounter thicker ice, difficult to break through, and the officer on the bridge would have to decide whether to try to push forward or back up and try another route. During this time, the Oden was running on 3 of her 4 engines, as planned for this portion of the cruise.This was planned for maximum fuel efficiency - using the 4th engine would allow the ship to break through the ice, but would use more fuel. So the officer would often back up the Oden and find an easier way through the ice. The officer would look for "leads", cracks or openings in the ice to follow, then maneuver the ship along the leads.
The crack in the ice floe widens as the Oden moves by.
The larger ice floes are broken into smaller ones.
Today, the Oden started the major "icebreaking" part of our expedition - clearing a channel from the open water 20 miles across frozen McMurdo Sound into McMurdo Station, our final destination. This was a much different operation than I imagined it would be. I assumed the ship would just break through the ice like we had done in the heavy pack ice earlier in the cruise and heavy in a straight line to the land. The land is actually Ross Island, but it is hard to imagine it as an island because it is always connected to the continent by thick ice and snow. Ross Island is where many early Antarctic explorers began their treks inland.
The Oden was contracted to icebreak a channel into McMurdo Station so that other ships could get into the US science station. The Nathanial B. Palmer was a few days behind us, also on their way into McMurdo. Then supply ships will also be coming into the station, as well as other science ships and sometimes even a tourist cruise ship or two. Supply ships are essential for bringing fuel, vehicles, building supplies and larger science items, as well as for taking away all the garbage and waste generated by over 1000 people who live and work at McMurdo. Airplanes can land at McMurdo from late September to early March (depending on weather,) but ships can only get through from January to early March, and only if an icebreaker clears the channel, so Oden had a very important job to do. But the ice in McMurdo Sound is "fast" ice -solid, unbroken ice attached to the continent, and would require a different type of ice breaking than we had experienced earlier on this expedition.
The bow of the Oden pushes up, over , and through the thick, fast ice of McMurdo Sound.
The Oden breaks a ship-wide channel into the ice, then backs up and repeats on each side to widen the channel.
Captain Mattias Peterson explained that they would break a wide (about 3-4 ship's widths) channel, with the channel mouth, or opening, extra wide to allow the broken ice pieces and small floes to blow out or drift out to sea, instead of clogging up the channel. As the Oden breaks through the ice, she leaves a trail of broken ice, from slush up to pieces meters in diameter. A wind blowing off shore would help the clearing process, while an onshore wind would definitely hinder the channel clearing by blowing the ice debris back into the channel.
The Oden leaves a trail of broken ice in her wake as she breaks the shipping channel into McMurdo Station..
The ice in McMurdo Sound is turning out to be thicker and stronger than anticipated. The Oden pushes ahead about 1-2 ship lengths over and through the thick ice before she comes to a stop. Then she is put into reverse and backs up along the path she just broke. The officer at the helm then sets a new course next to the broken ice, overlapping it a little. The Oden pushes forward again, widening her original path. When she rides up on the unbroken ice, the ships rocks and rolls jerkily from side to side, with loud crunching and grinding sounds. Then we have a few seconds of silence, before she reverses into the ice "debris, " now shaking and rattling like shaking a tin can full of rocks. Then, another few seconds of silence as she stops, then moves forward again, loudly breaking a new path. And this continues day and night! I sleep with ear plugs to dull the noise, which seems to help a little, but we aren't getting a lot of quality sleep right now! The ship is averaging about 1 nautical mile of forward progress every 4 hours, and we have about 20 miles of ice to break to get to McMurdo Station.
The "best case" scenario of 3-days icebreaking and arriving into McMurdo Station on January 13 and the science team flying out to New Zealand on January 14 is not going to happen. Now we have an anticipated arrival into the station late on the 14th and tentative plans to fly out on January 15. I understand why everyone emphasizes "FLEXIBILITY" and "RESHEDULED" when discussing travel plans in Antarctica! But even with these delays, i will agree with the Oden's claim that she is "probably the best icebreaker in the world."
Click here to see some of the ice breaking process
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