[BITList] Fwd: Centaur identified with video footage

[John Feltham]

Just in from a friend who served with BP Tankers and later laying a pipeline across the Straits of Gibralter. I thought that some of you might be interested.



Hi John,
 
I had experience of some of this undersea technology while working with the offshore sector,  as our ships were built forsurvey, diving and subsea exploration work and then for general supply when not otherwise engaged.
 
I was involved in laying a duel pipeline across the Straits of Gib one summer and one of our ships carried out the pre-lay subsea survey to make sure there were no obstructions.
 
The seabed from Morocco to just east of Cadiz was smooth rock,  with currents at the upper layer flowing into the Med and at the lower layer flowing out.  The latest current atlas was pre-war (WW1) and so it was going to be a tough one and there was a big conference in Amsterdam before it started for all the Masters to discuss all aspects of the operation.
 
Our pipelayer was the 'Castoro Sei'  (worth googling) which pulls itself across the ocean using a set of 12 anchors which are shifted by very large anchor handlers.  A fascinanating and technically complicated operation.  The pipeline is concrete coated to make it sink and to protect it on the sea bed.  Sections of 3 x  40 foot lengths are welded on to the ship end of the pipe and then the C6 pulls itself forward (backwards actually - she's Italian) 120 feet,  then stops while the next set are welded on...  about 6-8 minutes per section.
 
As one of  the pipe supply vessels we had to navigate in between the 6 anchor wires on one side then hold exact position 6 feet off and parallel to the barge,  with anchor wires passing over either the bow or the stern.  As she starts laying we then have to keep up with her,  and stop when she does so that we don't race into their anchor wires.  Mind-concentrating stuff. 
 
The pipes are lifed by a crane on rails lowering a 37 ft beam with slings at each end.  For each pipe the loop of one sling is slipped over one pipe end projecting out of the concrete (bare pipe ends to permit welding the joints together and then covered with hot bituman),  and the other sling over the other end of the joint. 
 
Depending on the weight of the pipes,  there may be up to 4 in one lift,  meaning 4 slings to be slung each end.  One seaman at each end.
Great,  in calm seas.  Once we and the barge start rolling,  life gets 'interesting' for the two seamen on deck.  Explains why they wear rigger boots as their feet can slip out if caught.
The larger pipes, weighing up to 20 tons each,  are slung singly.
We carry 4 stacks of pipes,  with layers reaching above the side crashbarriers.
Of course,  once we get to the bottom layer,  there are only a few wooden chocks to stop the jonts rolling across the deck.
The crane drivers are the highest paid anywhere,  and are V. good,  which is just as well.  3 mistakes and they are sacked.
 
For this particular pipelay,  and because of the smoothness of the sea bed.  the C6 normal 12 x  8 tonne anchors (3 at each corner)  were swopped for 40 tonne highgrip specials.  Unfortunately only one of the anchor handlers could lift these so had to do all the work - the other two just standing as guard ships  backing up the Moroccon gun boat trying to keep passing traffic outside our moving 5 mile exclusion zone.  Modern navigators seem to have inked courses on their charts and don't seem to appreciate that they can deviate when they encounter a 10 ship operation such as ours.
That aspect was quite hair-raising.
 
Anyway,  the point of the storey is that,  even with these highgrip anchors,  the pipelay snaked around quite a lot, mostly missing it's planned route,  and when our ship did the post lay survey they found the two pipelines wondering all over the seabed,  and at one place where they came close together they saw on the monitors that the pipes had landed either side of an  old moored mine!
 
Did I telll you of the phosphor bombs distrurbed by a pipelay we did across the Irish Sea?
Now that one is Really intersting,
swing that lamp!
 
Just received the attached from one of my Chief Engineers who is now a newship build super.  The exploration drillrig is being fitted over her moonpool.
Note the vertical yellow stabilisors - these keep the rig vertical while the ship rocks and rolls around it,  otherwise the drill pipe would snap....which is not good
 
Offshore ops are certainly not in the most pleasant parts of the seas and I quickly learnt to be seasick after 20 years on tankers,  but it was never boring.  The ships are just great big toys, always at the leading edge of technology (ours were Rolls Royce designed)  and  remarkably adaptable for all sorts of jobs,  and I was additionally lucky in that as the deep sea tanker fleet shrank from 90 ships to 35,  many of the senior staff moved into offshore ops,  and  I was continually meeting them again either in the shore offices or on the platforms, rigs, helicopters etc.,  which certainly made life much easier and interesting.  I was able to take early retirement just as the beaurocracy began to make like unendurable.



ooroo

Bad typists of the word, untie.




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