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June 24 - Another week in the North Sea

Date: Sunday 24th June 2007

Position @ 1200 Local (GMT): 59°16.7 North, 001°30.8 East. Alongside Harding Platform.
Next destination: Aberdeen, Scotland UK.
ETA: Wednesday 04th July 2007.
Distance to go: 95.5 nmiles.
Distance This North Sea Season. : 1498.5 nmiles since Immingham..

Position Click to Enlarge.

Up to date position information is available courtesy of ‘sailwx/info’ taken from our Metrological Observations..


From the chart pictured above, you will see that we have moved from last week's position on the Western Side of the Shetland Islands to the East and are now alongside the Harding Platform in the Northern North Sea. It was nice to say 'Goodbye' to the North Atlantic as the waves were higher and the weather more inclement than we are having in this location. It is also nice to be able to 'tick' another box on the job list and move onto the next task. You will therefore understand that the Shackleton has been continuing with our program of ROV work alongside Offshore Rigs and Platforms and we have managed to work every day since the last report.

That does not say that 'the course of true ROV'ing runs smooth' because we have had our fair share of technical difficulties, but all difficulties are overcome as they arise and nothing yet has stopped us working around the clock, 24 hours, 7 days a week.

Everybody on the vessel has now settled into well-oiled shift rotas and developed routines to help the days simply fly by. Even I have managed to get back into the swing of the 'fitness' regime and am visiting the gymnasium or 'trimnasium' most evenings !


Having finished our program of work on the Clair Platform, and with a forthcoming Crew Change due for the Charterers onboard, it was deemed that we could call in at Lerwick, in the Shetlands, to save on the necessity for a helicopter - or helicopters. It's cheaper. It's less organization. It's a chance to also obtain some fresh provisions and spares. Since Lerwick was almost on a straight line from the Clair Field to our next location on the Harding Field, we were not going out-of-our-way to make an unscheduled port call.

But we didn't entirely avoid helicopters this week.

To begin with, as we were on passage towards Lerwick on a cloudy Wednesday morning (20th June), there was a call on our VHF Channel 16 Marine Radio from an S61 Coast Guard helicopter G-BDOC. 'Had we any objections to the Aircraft practicing approaches to our decks ?' which of course we did not. On this occasion, HM Coastguard were only practicing approaches and did not need to practice lowering any personnel down to our decks on a winch, as they have done in the past. Here are a couple of photos taken of the operation prior to entering Lerwick's Bressay Sound.

Click to Enlarge the S61 Helicopter Click to Enlarge the S61 Helicopter


Enlarge G-BDOC departing to continue with Coast Guard duties.

We arrived alongside in Lerwick in time for lunch and to be met by the oncoming crew who had flown to the Shetlands that morning. The similarity between arriving at Lerwick in the Shetlands and arriving at Stanley in the Falklands is remarkable. They are both barren-looking expanses of rock in the middle of a grey sea and trees are never very much in evidence in both places. Both ports are well-hidden natural harbours and allow some marvellous views as we navigate through the narrows to reach the quayside. The difference here is that we use a Pilot to navigate the ship to the Quayside in Lerwick whereas we are able to navigate ourselves through the narrows down South.

 Lerwick Arrival Click to enlarge the distant image of the Shetlands,.. or is that the Falklands ?

 On departure, the Shackleton must navigate through narrow channels.

But our visit in the Shetlands was a very swift visit indeed and by 1600 hours, we had 'let go' lines forward and aft and with a Pilot onboard, we departed Lerwick once more for the Oil Fields of the North Sea.

We arrived on the Harding Field by midnight that evening.


Once on location, we went through out Pre-DP Arrival checks and went directly back to work. This time we were not right up alongside a platform but using the ROV's to inspect sub-sea installations 140metres below the surface. The Weather remained grey, but nevertheless fine and clear. And the morning brought the manditory Fire and Boat musters.

With every change of personnel on the ship, Micky Quinn the Purser gives an induction to the new-joiners and as soon as possible thereafter the whole ship has an emergency muster drill. This is to ensure that everybody knows where they should be and what they should do in the event of Alarm Bells ringing onboard. The drill went with usual smoothness and all the lifejackets and emergency equipment were returned to their stowage ready for the next eventuality.

But the RRS Ernest Shackleton was not the only crew doing Emergency Drills on that Thursday morning.

The nearby Harding Platform was involved in a full-blown exercise involving it's Standby Vessel, a Fast Rescue Craft and a Helicopter too.

 CG Puma Click to Enlarge a Helicopter trying to land on a Fast Rescue Craft ?

In this instance we were lucky enough to see the Puma helicopter attempting to land a crew member onto the aft deck of the launch. Maintaining speed and direction, the Helicopter dogged the Launch matching speed and course until the winchman ( resembling an 'extreme sports waterskier' ) could creep up slowly on the Launch and board her.

 Puma 4 Click to see the Helicopter Crewman deposited safely on board the Launch.

The pictures do not do the action justice and it really was a remarkable effort of the Pilot(s), Winchman and Launchman to complete the exercise successfully.

All in a day's work for the Coast Guard no doubt.

This weekend is still grey, but it has brought some really balmy weather here, halfway between Scotland and Norway, in the North Sea.

Perfect weather for one of the operations we have on our worklist.

On Friday, we launched our own Fast Rescue Craft to do an 'under platform' inspection of the legs and hull of the Harding Platform.

These Rigs and Platforms undergo periodical inspections for condition and security and this time the Shackleton's FRC was instrumental in taking a video/camera inspection team under and around the legs of the Harding Jack-up Platform. Luckily, I found a cameraman to take the ship's web camera with them to boldly go where no Shackleton web-camera has gone before.

Perfect conditions Perfect conditions for the ensuing Operation.

Mike Golding  Oil Rig

2nd Officer Mike Golding at the Helm, drives the FRC to the Harding for a leg inspection.

Underside of the Harding Click on Images to Enlarge. Underside 2

Looking upwards at the Installation. She may not look pretty, but who can get to the underside with a paintbrush ?

...and finally we revisit an article published in one of our first webpages but just as pertinent today...

By an Ex-Oil Rig Worker.

Before having set foot on an oil rig or platform of any description, it was amazing to think that I knew nothing about them whatsoever. Subsequently, I discovered friends and family ashore equally had no idea of the variety of installations there are working offshore. Basically they fall into 4 categories, or 5 if you count the ones that the Texans build on the land and have 'nodding donkeys' pulling the oil out of the ground. (you've all seen Dallas !).

The Platform is the final stage in offshore gas and oil production. Once the surveys have been carried out and the drilling rigs have been in to estimate the potential of a field, then the Platform is built in order to facilitate the removal of the 'product' from beneath the sea bed. The Platform is a structure which is fixed in location and looks like a monstrous lollipop with most of the weight situated high above the waterline on stilts or a tower, or 'jacket'. see picture. They always look 'top-heavy' and leave you wondering 'why don't they topple over' ? They really are a fantastic piece of design and engineering. Once the jacket is sunk into place - either metal or concrete in construction - then the 'plant' and accommodation is placed on top and there it stays for the length of it's working life. There are Platforms in the North Sea that date back to the early 1970's, so they are not necessarily 'short term' structures.

Platform (S) Click on image to enlarge Plan Section (s)

A platform and a plan section of a platform

The Rig is the penultimate stage in Oil and Gas extraction. Once seismic surveys have established the probability of product under the sea bed, it is the job of the drilling rig to explore the possibility of exploiting the find. Unlike the Platform this is not a fixed structure, but mobile, allowing the rig to be used throughout the oil and gas fields and indeed, worldwide. I have worked on rigs that have spent a long and productive life in the North Sea only to be towed off to a future life in the South China Seas and the Far East. They really are that mobile. These 'floating rigs' fall loosely into two varieties. The Semi-submersible, and the Jack-up type rigs.

The Jack-up Rig is exactly that. A structure with 3 or 4 long legs which can be lowered and once firmly established on the sea bed, further 'jacking' can lift the drilling/accommodation structure high above the water level and away from the forces of the sea. When you see the apparent flimsiness of the legs - some tubular structures and other solid metal - it leaves you wondering how they can bear the weight ? Once jacked up in position, these rigs are very stable platforms from which to drill deep into the earth's crust. So stable infact, that I have seen pool tables installed on these type of rigs.

The main limitation of the Jack-up is that is it restricted to the shallow waters where the length of leg can reach the bottom.

 Jack (S) Click on image to enlarge Jack Plan (s)
A jack-up rig and a plan section of a jack-up rig

The Semi-submersible Rig alternatively is an ingenious vessel which is more akin to a ship than an oilrig. The usual arrangement is for a low profile drilling platform and accommodation to be mounted upon two or more 'torpedoes' which form the hull of the vessel. Just like some strange catamaran. When in transit, the torpedoes are 'pumped out' which allows them to float on the surface and the rig can be towed into position. Some semi-subs even have their own propulsion systems and can make headway on their own ! But once on location, the torpedoes are flooded and the additional weight makes the rig 'sink' way down like an iceberg with the majority of the structure below the waterline. This gives stability against tides and weather, but unlike the jack-up it has no 'fixed' connection to the seabed to keep it in position. So this is effected by an array of anchors on chains that emanate from the rig in all directions. As can be seen, this leaves an arrangement similar to that of a grotesque water-spider just below the surface. The anchor chains are kept on tension and this effectively keeps the rig stationary despite the best efforts of wind and weather. There have been occasions when anchor chains have parted but with 8 or more chains taking the strain, there is plenty of allowance for the odd loss.

The main advantage of the Semi-sub is that it can work in deeper waters and only the length of anchor chain limits the depth of water in which it can operate.

 Semi-submersible rig (s) Click on image to enlarge Semisub - plan
A semi-submersible rig and a plan section of a semi-submersible rig

The other type of rig is actually a Drilling Ship . The Drill ship is a purpose built (or converted) seagoing vessel which has been adapted particularly for drilling operations. This uses thrusters and propulsion units in order to maintain position over the drilling site and therefore is not restricted to depth of seabed limitations. It is also very transportable and has arenas of operation throughout the world. This is what the Ernest Shackleton - Drill ship might look like !!!

 Ex-North Sea Rig Pig Click on image to enlarge photograph.

Author - Ex-North Sea Rig Pig

Forthcoming Events: Complete our Workscope on the Harding and move off to our next work site.

Contributions This Week : Thanks to HM Coastguard for some great helicopter photo opportunities. Also thank you to those members of the public who have reported back to BAS to say how well-appreciated the web pages are every week. It makes the job so much more pleasurable to hear that there are people out there who are actually READING this stuff. I certainly don't !!!

North Sea Diary No.4 will be produced on Sunday 1st July for publication on Monday 02nd - operations permitting.

Stevie B

Radio Officer.