This is an article written for a marine magazine many years ago, featuring the Venture I,  an old Pentagone which was drilling piles at Northwest Hutton for the later development drilling operations. This is so long ago that the platform has been installed and dismantled in the interim. The vessels involved in this operation were the OIL anchor-handler Oil Driller and the Smit-Lloyd 108

The sister ship pf the Oil Driller - Oil Mariner.

Shifting an oil rig is still one of the most demanding and interesting tasks available to the mariner. It requires seamanship, judgement and shiphandling ability on the part of the master, and knowledge and teamwork on the part of the crew, together with a healthy awareness of the potential dangers. This is an account of one of the most intensive anchor handling operations ever undertaken in the North Sea. I do not claim that it was the most difficult, but what was expected of two old ships and twenty men years ago would tax even the most modern craft available today.

In July 1979 I was master of the Ocean Inchcape anchor- handler the Oil Driller. This was a vessel of some 7000 bhp, powered by twin English Electric V-12 engines, and by today’s standards a low power and spartan craft.

During the second week of the month we lay at anchor outside Aberdeen, purely to save port dues since the ship was on the spot market. To those unfamiliar with the manner in which supply vessels operate in the North Sea and elsewhere, the way in which vessels are hired is infinitely variable, but is based on a day rate, the charterer usually paying for the fuel and lubricating oil used in addition to a sum for each 24 hours of hire. Beyond this the hire period may be for 12 months, six months, one week or one day, or even one well, with options to extend any of these periods, at which time the day rate may be renegotiated. The rate depends on the number of ships available at the time, and the fewer ships there are available the longer the period of hire is likely to be.

One of the advantages of hiring ships for long periods is the familiarity gained by the charterers with the vessels, giving them an awareness of the capability of the craft and their limitations if any.

However, when particularly complex or difficult rig shifts are likely to take place, the oil companies often have to hire in extra craft to assist with these tasks, which results in them taking on vessels with which they are unfamiliar. They must therefore rely on the expertise of the ship’s crew and the specification of the ship, without really having the detailed knowledge which one would think necessary for what is probably the most difficult offshore activity.

In this situation Amoco went into the spot market and hired the Oil Driller to assist one of their long term vessels, the Smit-Lloyd 108 in the shifting of the Venture 1 on the location of the North West Hutton platform.

HARBOUR MEETING 

Consequently on 13th July I took my ship alongside the Amoco berth in Aberdeen and was subsequently summoned to a meeting in the offices of that company where the details of the operation were explained. This in itself was an unusual step, the usual technique being to dispatch the ship to the location where it will subsequently be acquainted with the task to be carried out.

This shift was not simple since the Venture I was due to drill the wells for the North West Hutton through a template, during the period of the platform construction. It was therefore going to be on location for about two years. To add to the complications, the seabed in the area was littered with well-heads, and one of the anchor positions was on the other side of the Brent to Cormorant pipeline which passed the location to the North.

As a consequence the oil company had decided that the rig should be permanently moored in position utilising piles concreted into the seabed. The rig was to set these piles itself, and since it had ten anchors, ten piles were required, necessitating a minimum of ten shifts. It was not a job for the faint hearted.

The Venture I was a Pentagon rig, with five legs having two anchors on each leg, the anchors weighed 30 000 lb and each was attached by means of nearly a mile of 72mm wire. The five legs were lettered A to E, A being the port aft leg and E the starboard aft leg, so that the nominal bow of the rig was the C leg. This leg had atop of it a tiny pilot house, and this always faced north west, the direction of the prevailing wind.

ON LOCATION

We arrived on the location in the evening of the 14th July to find the rig already in position to set the first pile, this was obviously Al. Our partner in the operation the Smit Lloyd 108 was closed up with the rig engaged in some activity which was not at the time clear to us. We went to anchor and awaited instructions. In those days the rig personnel were given to issuing information more on a need to know basis than anything else, and as a consequence ships not actually engaged in specific activities might not be aware of what was taking place.
The notes from the Oil Driller’s log indicate that we entered the fray for the first time at 1110 on 16th July. It is a significant moment for from that time on the events followed each other with bewildering rapidity, and it was not until 1st August that we were even to draw breath.


The shift started off in a predictable manner. Each supply vessel was instructed to make its way to an anchor buoy and pick up the anchor. We backed up to our buoy, the crew lassoed it and we pulled it on to the deck. After the usual foray with wrenches, hammers, chisels and pelican hooks the anchor pennant wire was connected to our work winch and we ponderously lifted the anchor to the surface at the stem of our vessel. The rig heaved its anchor wire and us towards it. Once close enough we returned the pennant to the crane and sallied forth, carrying out the same task with the second anchor.

For the purposes of this operation the rig was only using six of its ten anchors so the lifting of the next two anchors would result in it being free of the seabed. Since the distance between the pile positions was short, no more than l000m, neither ship was rigged for towing, the operation being carried out instead by leaving the last anchor some distance from the stern and towing on that, the rig’s anchor wire therefore becoming the tow wire.

While this technique saved time it meant that on both vessels the movement of the tow wire was restricted to the width of the stern, making turning extremely difficult. This was to prove to be an ongoing problem since in almost every case the rig was required to move away from one pile position and describe a complete circle to make an approach to the next.
For every shift the 108 took up position as the lead tug and the Driller as the stern tug. The master of the 108, unable to make rapid changes of direction was forced to use an alternative technique of moving the whole ship, and the anchor wire, sideways, describing an arc on the perimeter of a circle until the new heading was reached.

On the Oil Driller, being dragged along backwards even this method was denied to me so that when instructed to take up a different heading I was forced to resort to dashing astern faster than the speed of the tow, to slacken down the wire, and then to moving quickly in the direction of the new heading, but at ninety degrees to the direction of travel, hoping to get to the required position before the anchor wire tightened up.

Once on the second location we re-ran the anchors, buoyed them off and by 1730 had completed the operation. It had been a good start. We were briefly able to relax.

BRIEF SUMMER NIGHT

At 2am the next day, I found myself back at work in the brief summer night to the North of the Shetlands. We now knew what the 108 had been doing when we arrived. We took on to the deck from the rig crane a 50m pennant and a 550ft pennant, and these were reeled in turn on to the ship’s work drum, we also received a buoy marked with the pile number.

An hour’s work with messengers and tugger wires placed us in a position between the A and B legs of the rig, with the pennant wire disappearing over the stern, to be finally attached to the top of the pile, which though invisible to us was hanging below the drillfloor. By extending the pennant the ship was able to move a reasonable distance away from the structure, but nevertheless I was forced to maintain concentration for what turned out to be 21 hours, while the hole was drilled, the pile lowered into it and then cemented into position. On completion we were able to lower the pennant and launch the buoy, thankfully released like a dog being let off a lead.

On completion we tied up to the rig and replenished its water supply, and then at 0100 were able to retire for a brief rest period before shifting the rig once more from the A2 to B 1 pile positions.

By 21st July, day six of the operation, we completed yet another pile buoying operation and shifted the rig from the B2 to Cl pile positions. The Oil Driller had carried out most of the buoying job so that between shifts the 108 had been able to anchor and gain some much needed rest. I, on the other hand was beginning to suffer from severe fatigue, our rest periods being limited to a couple of hours at a time between the various phases of the operation. It was therefore a relief when the rig realised this disparity in activity and called in the 108 to take its turn on the end of the buoy pennant.

The shifts continued, the ships now taking it in turns to work with the rig for the periods in between, and so giving a work sequence of a rig shift, a piling operation, a rig shift and then a rest period. Survival was just about possible.

By 27th July, day 12, the rig was finally shifted to the E2 position, the last mooring. We were exhausted but the team on the rig were ecstatic. Things were going really well. In some ways the master of the 108 was worse off than I since his owners had not seen fit to equip his vessel with a seat from which to handle the ship. He was complaining of leg trouble.

PROBLEMS

We had other problems. Since we had no real idea of the length of the job we were beginning to run out of various supplies, starting with washing powder. The ship’s washing machine had been working overtime to keep up with the continuous use of boiler-suits, and our stocks of some basics, such as potatoes were beginning to run low. Such minor difficulties assume much greater proportions when fatigue shortens tempers and everyone’s time-clocks have been severely disrupted.

On day 13 we began a secondary series of shifts. The company had decided to equip the platform with a supply vessel mooring to North and South and it was to the first of these moorings that we shifted the rig, then, while the 108 carried out pennant duties we tied up and pumped cement to the installation to replenish what had been used to date.

Modern supply vessels can pump cement at between 80 and 100 tonnes per hours. The Oil Driller could manage 20 tonnes at best. We started pumping at eight in the morning, and after the usual delays we were still at it in the increasing gloom which passed for night. The weather worsened and on the 108 visible on our port quarter the deck was beginning to be lashed with spray, the crew shadows in the glare of the vessel’s deck lights.

At 0140 on 29th July, day 14, the cement transfer was completed. The weather had eased and the 108 had been able to complete its part of the piling operation. Our provision shortage had also been remedied. During the previous day we had sighted a passing company vessel and had been able to negotiate the transfer of essential supplies.

We spent the major part of the day moving the rig to the second mooring position and completed our pile location at half past midnight on day 15. We were then able to retire to anchor for some much needed rest while the rig prepared for the next phase which was to be the testing of the moorings.

There were now ten buoys in position at a radius of about a mile from the template position, and two mooring buoys close to the centre. By this time one of the buoys had been sunk by a passing supply vessel, but it had been recovered and replaced by the 108 using a grapnel to hook the pennant.

At 0100 on 31st July, day 16, we moved the rig from the second mooring position and started to connect it to the piles. The anchors had to be brought on to the deck and removed so that the end of the cable could be connected direct to the mooring. To do this we would run about 500 ft past the mooring buoy and then back up to it. In this way the rig wire would be slack, thereby minimising the problems of manoeuvering while still connected up.

The whole operation was completed in eight hours. By now we were a very finely tuned unit, constant practice making as close to perfect as it was possible to become. Not only that but the pace of the operation was slowing and we were gradually shrugging off the fatigue induced by the first two weeks of frenzied activity.

After nine hours the rig was ready to be moved once again, this time to a wellhead which was to be inspected and so we started disconnecting the moorings from the anchor cables, buoying them off, reconnecting the anchors to the anchor wires and returning them to the rig.

All went well until we pulled the connection to the Al anchor pile on to the deck. The pin in the spelter socket connecting the two had become slightly bent. During the tensioning up process it must have been twisted, the result, the rig apparently permanently connected to Al. We set to work with the largest sledge hammers on board, alternately battering the pin and then filing the end to remove the distortion resulting from the battering.

ESSENTIAL MAINTENANCE

After twelve hours and no success we obtained permission to get out the gas axe, cutting the pin in two, and proceeding thankfully to the next part of the job, leaving a damaged mooring on the seabed to be dealt with later.

The shift was completed in the evening of day 17, and while the rig personnel went to work on the well-head the two supply vessels did absolutely nothing other than catch up on essential maintenance, grateful for the rest, the summer weather and the fact that we were able to go to anchor.

On 5th August we mobilised and shifted the rig to a second wellhead, after which we were engaged in a number of peripheral tasks. We spent a couple of days attempting to locate other wellheads, firstly with the ship’s echo sounder, but to no avail, and secondly trying to release a wellhead marker using an electronic device manned by a surveyor on board the ship.

These electronic releases are devised so that they are held in contact with the object to be located until they receive a signal. They then bob to the surface to reveal the position. They have one failing. Sometimes they do not bob to the surface. This one did not. 

We also made a trip back to Aberdeen for rig supplies, water and fuel, being alongside in port from 1700 on 12th August until 0900 on 13th.

On 15th we commenced the first of three shifts, to the template location, to a wellhead and finally to the Al pile position so that the rig could renew the damaged spelter socket. These moves took until 20th after which both ships were engaged in recovering the ends of the mooring wires and making changes to the layout so as to avoid any further possibility of the Al incident.

On the afternoon of 20th we started to recover the rig anchors in preparation for the tow to Scapa Flow, where the Venture I was to be modified before commencing its two year drilling stint. At 2100 all the anchors had been recovered and the rig was sent on its way, being towed by the 108. We returned to the moorings to try to complete the modifications before leaving the location.

MOORING ABANDONED 

Within a couple of hours the weather was worsening and it became obvious that not only were we going to be unable to carry out much more work on the moorings, but if we did not abandon and catch up with the Venture I there would be little chance of us connecting our tow until the weather improved, possibly days away, with a consequent lengthening of passage time.

Accordingly we abandoned the moorings and set off for the rig, preparing to connect the tow as we went, finally making the connection at 0015 on 21st. The laconic log entry “Tow connected” conceals an eternity of tension.

Under the most favourable weather conditions to connect up to a rig which is already under way requires total precision and total concentration. The vessel already connected will bring the tow up into the wind and slow down so as to maintain steerage. The second vessel must then ease in ahead of the rig, and once within range of the deck crane, maintain position while the end of the towing bridle is passed down and the deck crew make the connection. The worst time for the master is when the bridle is connected to the deck, allowing little movement, so while he is in this unenviable position his attention is constantly being distracted by the activities on the deck. No matter how fast his crew is working their actions seems to take place in slow motion.

For the Oil Driller that moment was made worse by the fact that she was equipped with fixed-pitch propellers, clutches and gearboxes, rather than the more modern CP system. Since at no time could the eight seconds it would take to go from ahead to astern be afforded, it was necessary to approach with one engine going ahead and one astern, and to create a balance with the rudders and the bow thruster.

On the third approach, with black smoke belching from the funnels and the thruster engine revving furiously under the accommodation I got the stem of the ship under the crane, seemingly inches from the pontoons and held it while the towing bridle was passed down. The crew feeling the urgency and spurred on by the sound of the ship  straining to maintain position against the wind, leapt to their tasks and in what can only have been minutes connected the tow wire, knocked off the pelican hook and signaled to the chief that he could pay out. I thankfully moved away from the danger area and paid out enough tow wire to take up position close to the 108. We set course for Scapa Flow.

Effectively the job was done, we had carried out eighteen individual rig shifts, the first twelve over a period of sixteen days, an extraordinarily high level of activity for two relatively ageing vessels. We had spent six weeks almost continuously at sea, nothing for a deep sea ship, but unusual for supply vessels, and we were finally on our way home.

Our excitement was not quite over. The rig’s entry into Scapa Flow was delayed, resulting in our crew, and some of the crew of the 108 being basket transferred to the Venture I and sent off by helicopter, but the excitement of the basket is another story. The new crew towed the Venture I to Scapa, and the Oil Driller continued to work for Amoco, the 30 day spot finally lasting for six years. In that rather picturesque American phrase, it seems like “we done good”.

 
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