Saturday 14 April 2012

Day 18 Fog and a hair dryer

The ship heads into thick fog
Winch during gravity corer recovery
Hair dryer on winch cable
The winch cable is blow dried to remove salt water
Current Position: 53° 35' S, 39° 04' W, about 60 nautical miles from South Georgia. Since leaving the Falkland Islands 19 days ago we have travelled over 2500 miles. Unfortunately the ship is surrounded by thick fog once again. In this visibility the chances of spotting wildlife are very slim. On a clear day, the ship is always swarmed by sea birds - pertrels, albatrosses - but in the fog there's only a few solitary birds trailing the stern today. It's not only that I stand little chance of spotting wildlife as it's hidden by the fog banks - it's that the birds simply aren't around the ship as they would be on a clear day (a ship makes an interesting object to any animal in the vast ocean). The birds simply cannot see the ship or each other and won't congregate around it.

On the plus side, the sea is relatively calm - winds are down to 15 knots or so, and the churned up seas have slackened to a regular deep oceanic swell. Over the last few days the coring team has proceed with their science program. The aim is to find suitable coring suites on the northern slope of the North Scotia Ridge. During last night's survey work the sea floor was found to consist mainly of rock or hard sediments, so the search goes on for more suitable sites.

While the physical oceanography team is only doing the occasional CTD I had some time to snoop around the ship a little more. Whilst the gravity corer was hauled up from 2500m depth I discovered an ingenious little gizmo attached to the winch cable. It's known as the 'hair dryer' - a small box fitted around the cable and it's connected to a steady supply of pressurised air. It is turned on whenever the wet cable is hauled up from the sea where it naturally gets drenched in salty sea water. Anyone who's been near the sea knows that metal and sea water don't go well together. The salty water is incredibly corrosive, and spooling up a wet steel cable onto the cable storage drum would not be a good idea - the cable would simply rust and break very quickly.

This is where the hair dryer comes in - it blow dries the cable before the it is taken up by the storage drum (see photos above). As a result, the dry cable is much less likely to rust. Having seen the cable drying gizmo in action, I am sure this is pretty common practice with any winch system. I just thought it was a pretty nifty and simple solution to the ever-present rust problem at sea.

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