25 August 2010 Seamount Sweep

Journal

Speed 6.7 knots (kts) Course 312° Location North Canada Basin, 81.9° N, 136.10° W Depth 3693 meters

SPECIAL FEATURE DISCUSSION:

(see previous journal for the questions.)

Even a 420-foot long icebreaker like the Healy can get stopped by the ice. The first thing to try is to back up and then use the open path ahead to gain speed for another try. This is called backing and ramming. Icebreakers have special rudders that are designed to withstand going back through ice. If backing and ramming doesn't work the icebreaker can try to back up far enough to find another path around the obstacle. Occasionally, though, an icebreaker may find itself stuck due to pressure squeezing ice in on it. In order to gain a little maneuvering room one trick is to have one propeller turn clockwise and the other clockwise. This can have a pivoting effect which can open up a little space for the ship to get going again. Icebreakers like the Healy can also pump water back and forth in ballast tanks on each side of the ship to rock it back and forth in hopes of loosening the icy grip. Still, to guard against the possibility of being stuck for a while the Healy carries enough provisions in its freezers and dry stores for us to last until next spring if needed. Here's hoping it isn't!

TODAY'S JOURNAL:

When we found out the Louis would need a day or two to fix their propeller shaft bearing we headed north on our own towards a seamount discovered last year as the Healy serendipitously cruised over it. Once they realized this was an uncharted feature the ship cruised back and forth enough to map the seamount with its multibeam sonar, proving it to be about 13 nautical miles long and a little more than 5 nautical miles across at its widest. It rises around 1000 meters from the surrounding abyssal plain and is aligned nearly north-south along its long axis. Still without an official name, we refer to it as the '09 Seamount.'

Unnamed Seamount found on 2009 Healy Cruise — The so-called '09 Seamount found by Healy on its Arctic cruise last year. The map is created by our multibeam sonar.

On the way towards the seamount the ice got thicker, with substantial amounts of multi-year ice finally making an appearance on this cruise. It was certainly a change of perspective to be all alone in the ice without the Louis either leading the way or following us. At times it was nearly pure white from horizon to horizon with the exception of the track of open water we were leaving astern. Even that turned white fairly quickly as broken chunks of ice filled it back in behind us. We would sometimes encounter pressure ridges that stopped the Healy in its tracks. By backing up in our track and pressing forward again we could gain enough speed to ram our way through and continue on our way. We were tantalized by several more sets of polar bear tracks but no actual sightings of the mighty ice bruins. I did see a distant ringed seal that was hauled out on the ice getting some sun. When the ship got within about 1/2 a mile the seal slipped into the sea through its hole in the ice. These seals are preyed upon by polar bears and never stray far from their escape routes.

Healy Stopped by Pressure Ridge — This pressure ridge stopped us in our tracks, but by backing and ramming we could proceed on our way. Note the impression left by Healy's bow on the unbroken ice. We saw our most extensive multi-year ice conditions yet on the transit to the '09 Seamount.

Finger Rafting in New Ice — We periodically went through areas of new ice yesterday where openings in the multi-year ice were already re-frozen a few inches thick. Much of this new ice featured finger rafting patterns, caused as pressure squeezes the rectangular 'fingers' into overlapping joints.

Yesterday also brought a great opportunity to visit a part of the ship I hadn't been to yet, the Aloft Con. In yesterday's journal take a peek at the first picture, a view of the Healy as seen from the Louis. Aloft Con is the black tower above the bridge. It is the equivalent of 8 decks above the main deck and nearly 100 feet above the sea. From there the view is pretty impressive, and when we are negotiating ice the ship is steered ('conned' in naval parlance) from this high lookout. To get there you climb three sets of ladders from the bridge. These are dead vertical ladders inside of a tower, not the steep metal stairs called ladders between normal decks. If you wanted to go any higher on the ship you'd have to get outside and climb the mast above Aloft Con.

Bill in Aloft Con — Bill nearly 100 feet above the ice in Healy's Aloft Con.

Ladder up to Aloft Con — One of three ladder sections in the tower ascending to Aloft Con.

Today we took a core sample from the '09 Seamount. More on that tomorrow! We also have news that the Louis is repaired and steaming to rendezvous with us around midnight tonight.

Low Sunlight on Ice — We haven't had a sunset for a while now (we're too far north for that now at this time of year), but the sun still dips low enough in the sky for some dramatic lighting on the ice.

SPECIAL FEATURE:

Since we are hundreds of miles from the nearest land, where could a Polar Bear up here get a drink of water if it was thirsty after eating a ringed seal?

If you have been tracking the Healy's position lately you've noticed how fast our longitude has been changing. Can you explain how our longitude changes so fast while our latitude doesn't?

That's all for now! Best- Bill

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