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Davis Part Two

Subj: Davis Part 2

Date: 11/5/009:36:32 AM Pacific Standard Time

From. [email protected] (Gordon Bain (on Aurora)

Hello all

You don't have to believe this but it is 4:55 am on Sunday. Gordon was restless last night and woke up about 3:30 and decided we should as well. So we've had a nice cup of tea, put the laundry on, tidied up some paperwork, re-read a couple of e-mails.

And so to now, where we thought it a good idea to give you Davis Part 2 (even though we are now in the middle of our Mawson operation). In my main report about Davis, I promised three further things -the fuel oil transfer, how we broke back out of the fast ice and also something about the cargo we are taking back to Australia.

Fuel Oil

The power at the stations comes from powerhouses which generate power by burning diesel oil. The diesel we use is a very light grade without the waxes found in normal diesel. This is on account of the very low temperatures in which we have to operate - at low temperatures the waxes can separate out and clog filters and so on,

The exercise is simply to transfer fuel from the bulk fuel storage facilities in Hobart to the bulk storage facility at Davis. You might remember me telling you that before we left Hobart the ship moved from Macquarie Wharf where we loaded cargo to Selfs Point for 'bunkering'. At Selfs Point, which is the bulk oil storage facility for Hobart, we loaded two types of fuel -'bunkers,' a Marine Gas Oil used on the ship for its engines and propulsion, and SAB (Special Antarctic Blend) that is used for powering the station power houses. We loaded 640,000 litres of SAB - you might remember telling you about what that figure means when I told you about the cargo we were carrying on this ship.

So, we set sail with the SAB in special storage tanks on board the ship. When we reached the anchorage point at Davis in the fast ice, our task was of course to transfer it to the bulk storage tanks on the Station. These are located at the top of a low ridge above the station -about two hundred metres from the shore, and we were parked about 3 kilometres off shore.

The system is basically fairly simple - a hose line from the ship running to the 'fuel farm' on the shore. We carried the hose line with us - it is called a 'lay-flat' because it is flat when empty. The hose is in 200 metre lengths, each length on a spool, 10 spools to a big reel. Each spool is just a bit bigger than the width of the hose and around 2 metres in diameter, the spools are side-by-side like a bunch of stacked coins but on their side. We had two reels, giving us a total of 4 kilometres of hose, but this special hose is only used to reach the shore line - there it is attached to a fixed system which runs up to the fuel farm.

The lengths of hose are joined together and because of the distance over which we pump, we install a booster pump part way along the line to give an extra push, particularly for the last uphill section. There is also a compressor on the line at the ship end, but I'll explain its purpose a bit later.

So the whole system comprises - the ship, its storage tanks, its pumps to draw the oil from storage and push it along the line, the compressor set up near the bow of the ship, the hose line running over the surface of the ice - all the way to the shore, a booster pump close to the shore end, a fixed pipe (called a Stand Pipe) on the shore to which the hose line is connected, the fixed hose running to the fuel farm storage tanks. There are of course various gauges and meters at different points in the system.

The hose reels were taken out of the ship and put on to the ice near the front of the ship.

 Stopped at 0545 for a shower and change, 0630 meeting with Chief Mate and Bosun, 0730 meeting with Chief Pilot and Captain and radio sked with Voyage Leader who is at Mawson, 0745 Breakfast, 0800 -started work with cargo etc. Resumed this e-mail 1838, first opportunity. All Mawson operations completed, vessel is   working its way back out of the ice heading north toward Heard Island and our next Operation -probably another six days. Will write about Mawson operation separately and later. But for now let's get back to Davis Part 2.

The lengths of hose are drawn off the hose reel and dragged across the ice behind a Quad (a 4 wheel bike). These are laid out in an approximate line, nose to tail, and then the work team comes along and joins them together. The connections are then tested by blowing compressed air along the line and every joint is thoroughly checked for signs of leakage. Joints are then tightened or parts replaced and the process done again, and again until all are happy that the line is intact. And only then, does pumping start. While the pumping is occurring there were people dedicated to monitoring and watching every stage of the process, including constant patrols by vehicle of every inch of the pipeline looking for any evidence of spill. Pumping rate is monitored regularly at both the ship and fuel farm ends, and tanks are 'dipped' regularly to measure the volume transferred.

And when pumping is finished, the next problem - what do you do with the oil that is sitting in 3.5 kilometres of hose line? If the line is 125mm in diameter- how much oil is that? Obviously you can't just let it run out - you might as well save what you can and it is not good to pollute the environment anyway. The answer is you 'pig' the line. Eh? Well, you send a pig down the line to push all the oil in front of it into special storage bins, which can then be taken to the fuel farms and added to the storage tanks. A pig? Not a real one surely? Actually it is a firm torpedo-shaped foam rubber gismo which just fits inside the line and is propelled along it by a blast of compressed air - this purges the line of excess oil. In the early days of this kind of technology in the oil industry the lines were a lot bigger and correspondingly the 'pig'; the early devices were also pink -hence 'pig' came the expression. As each length of line is disconnected it is fitted with caps and when rolling up the reel starts, the cap at the 'far end' is removed and as the hose is rolled on to the reel any oil still in the line is squeezed out into a special storage tank attached to the end of the hose.

So it is a very careful operation designed to minimize the risk to the environment and it is also a very efficient process - particularly going over the hard sea ice.

How long did it all take? And how much did we pump? Well, the team started laying out the hoses at 3:00 pm Thursday, connections made and checked pumping commenced 6:30 pm Thursday, pumping stopped at 3:45 pm Friday, the line was pigged and purged, checked and rolled up for stowage back on the ship at 9:30 pm Friday. A total of about 30 hours - and we pumped 630,000 litres of fuel. How long would it take to pump that amount into a car at a gas station (assuming there was enough fuel at the petrol station and you had a big enough car to take it?

So that's it about fuel pumping - as practiced at Davis. The same principles are applied at other stations but each has its own unique time and way of handling the exercise.

Getting out of Davis

We were at the bottom end of this 9 kilometre channel we had carved through the fast ice - only as wide as the ship and apart from a small area immediately behind the ship, the broken ice in the channel had frozen solid again. If you are driving on a very narrow road and want to turn around and go back the way you came in, how would you do it? The technique in driving is called a three point turn - check it out with someone who drives if you need to. Well, it is actually the same technique but it is a bit harder with a ship and such a narrow channel. Many years ago Gordon started using the term "60 point turn." It's not 60 but it sure is a lot of back and forth - the ship goes forward, makes a bit of a swing and cracks off ice at the top of the channel. Then it backs up and knocks a bit more off further down the channel. Then it goes forward making a slight change of direction and bites off another chunk, then back and forth turning a little more each time and gradually making the "hole" at the end bigger. Eventually the ship had made a big "bulb" at the top of the channel and the ship had got to being at right angles to the channel. Once we'd achieved that it was easy - the ship made another forward move and this time it had a circle in which it could keep turning until it was facing down the channel. And then it was only a case of steering down the channel. But even though the broken ice had frozen up solidly, the ship had no problem re-breaking it and we made it to open water off the edge of the fast ice.

It took us some 13 and a half hours to break through the fast ice to get to the anchorage point; it took us an hour and a quarter including the "60 point turn" to get back out!!!

It's just getting a bit near to the close off time for the next e-mail cross, so I'll stop now. I still need to tell you about the sort of cargo we picked up at Davis, and then something about our journey to Mawson. The Mawson operation will be in its own episode.

Bye bye for now

Berkley, OzGold, Dreena, Puff, Olly, Millie and Syd and not forgetting our host Gordon


 

 

 


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