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Towage and Marine Operations

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  • ombugge
    replied
    Re: Towage and Marine Operations

    AHTS Capricorn (ex Schelde, ex King Supplier, ex Arvid Viking, ex Northern Comrade) hooking up towline to a casualty in less than ideal weather.

    Preparing the tow wire:


    Anchor and chain from the casualty pulled on deck. Making connection:


    Salvage crew returning from the casualty after the job on their side is done:

    Not for the fainthearted to do a basket transfer in these conditions.

    Tow progressing towards safe heaven:




    PS> Capricon was one of the last UT 704 Mk. III to be built. Launched as Balder Schelde in 1985 by J. Patje, Holland.

    PPS> Photos curtsy of the Master, AHTS Capricorn.
    Last edited by ombugge; July 31st, 2013, 11:24. Reason: Add PS

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  • ombugge
    replied
    Re: Towage and Marine Operations

    This thread has been neglected, by me and everybody else.
    I take this opportunity to bring it back to life by showing a large barge with a jacket on deck leaving from Lumut, West Malaysia last week.

    A familiar looking vessel coming into view behind the threes:


    Aha, it is the POSH Persistence:


    But she is moving slowly. What is she towing??
    A semi-submersible cum launch barge. The POSH Mogami:


    With a Steel Jacket on the launch beams:


    The local tug Gerak Tegas is escorting at the stern:


    I had nothing to do with this operation and don't know where they are heading.

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  • janihudi
    replied
    Re: Towage and Marine Operations

    that is indeed a ''bible'' ,a lot of types of anchors and also how it al works.
    never thought of ,that that little place was a world leader of that kind of anchors,but then again,i only know vrijhof Rotterdam.

    Leave a comment:


  • ombugge
    replied
    Re: Towage and Marine Operations

    Originally posted by janihudi View Post
    you 're talking here about vrijhof anchors.
    thus that mean that vrijhof is a brand/devolopper factory of anchers?
    and not a supplier of anchors.
    Vryhof is both developer, manufacturer and supplier of anchors, incl. special purpose anchors for the offshore oil and gas industry.
    They also develop and manufacture anchor handling equipment. They are world leader in their field.

    Here is a link to their web site and the "bible" of anchors, anchor handling and technology: http://www.vryhof.com/anchor_manual.pdf

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  • janihudi
    replied
    Re: Towage and Marine Operations

    you 're talking here about vrijhof anchors.
    thus that mean that vrijhof is a brand/devolopper factory of anchers?
    and not a supplier of anchors.

    Leave a comment:


  • ombugge
    replied
    Re: Towage and Marine Operations

    Originally posted by janihudi View Post
    so i reken that the price of a new anchor is so much higher, than the costs for try to pick up a lost one from the seabed?
    Yes Thijs, a 7.5 t. Stevpris is worth a lot more that it's scrap value.

    An anchor may not sound like a "high-tech" item, but a lot of experience and research has gone into the design of the Vryhof anchors.

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  • janihudi
    replied
    so i reken that the price of a new anchor is so much higher, than the costs for try to pick up a lost one from the seabed?

    Leave a comment:


  • ombugge
    replied
    Putting it to good use:




    Piggy backing:






    The Bridge during anchor handling:


    Not very practical lay-out of the Control Panels. The Ch. Engineer operating the winch is blocking the view for the Captain handling the boat. That is what you get when somebody with no practical experience gets to design the bridge.

    To make it worse they hired the smallest Indonesian Captain and the biggest Pinoy Chief they could find.
    Last edited by ombugge; October 25th, 2010, 12:10.

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  • ombugge
    replied
    In another thread there was a discussion about Grapplers and what they are for.
    Here is one being used to find and recover an anchor that had been missing on the seabed without anybody having recorded the exact position. All I knew was what the anchor had been used for.

    Using a Grappler tailing behind a boat and running lines diagonally across where logic told me the broken wire and chain was likely to be, we managed to get a grip on the chain and bring it on deck:


    The 7.5 m.t. Stevpris Anchor is on deck:


    Good as new after two years lost on the bottom:




    Two more missing anchors escaped "capture" and is still there, somewhere off Kelantan, Malaysia.
    Last edited by ombugge; October 25th, 2010, 12:12. Reason: replacing pics

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  • pilotdane
    replied
    Very interesting to watch the operation. Even though I've see photos of all sorts of mega operations I am still amazed when I see the people standing next to the lifting hook and piles. They look big but then when you see people next to them they become huge.

    Hearing you tell of weather windows. Missed that window, get back to a stable position and wait for another window. Is another side of the story that is not often said. I am accustomed to see such operations condensed to a one hour long TV show. It's interesting to hear more of the troubles and long delays waiting for the weather, though I'm sure you would call it something other than interesting when the jacket was dancing around trying to take the crane to the bottom.

    Leave a comment:


  • Seagull
    replied
    Just a quick post to say yes, it is of considerable interest –a riveting and satisfyingly detailed words and pictures account of the technical acomplishment and challenges involved in such an operation, and, it seems, intertwined with a very personal story. Greatly appreciated that you shared this.

    Leave a comment:


  • ombugge
    replied
    A great relief for everybody, but it was still left to secure the jacket with piles.
    The Barge HD 2007 alongside with the piles:


    First pile positioned for upending:


    Upending in progress:






    I only got to see the first pile set, as I was relieved at 1510 hrs. 30. March and left the HD 2500. That same day at 2210 hrs. I was admitted to hospital in Hong Kong.

    I long post, but I hope it is of interest to some here on CVF.

    Leave a comment:


  • ombugge
    replied
    The jacket was towed in circles around HD 2500 by the two Britoil tugs until 27. March.
    11 days with many of the rupture discs on the jacket blown and only the air valves holding the water to flood the legs. Not a very good situation to be in.
    It looked like another weather window, long enough to unend and set the jacket was in the offering, finally.

    On the 28. March at first daylight the jacket approached the stern. Waiting on confirmation that predicted lull was sufficient to accomplic the operation, incl. setting at leat two piles, before the weather deteriorated again. (We were now coming close to the end of the NE Monsoon season):


    The weather forecast for the next 48 hrs and outlook to 72 hrs. was within the criteria of 1.5 m. seas and it was approved to commence the upending operation.
    The jacket was brought into position again, upended:

    And set down on the prepared template. According to my log; 1220 hrs. Jacket on bottom. Slacked off on slings:


    And there it was, standing proudly by itself, the HZ -19 Jacket:

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  • ombugge
    replied
    The next day, as the weather had deteriorated further and the forcast was not good, it was decided to add more mooring lines and to de-ballast the legs.
    To do this meant sending people back on the jacket:

    Finally, with the jacket floating with one face in the surface, we could slack off on the hook to avoid any risk of shock loads:


    The situation remained the same until 16. march, when there was a short weather window. Not long enought to upend and set the jacket, but sufficient to get the jacket away from the HD 2500, before the weather deteriorated further.

    That ment disconnecting the slings and hoses, re-instate the bridle and let go the mooring lines:




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  • ombugge
    replied
    That is when the problems started. This jacket was not self- upending, (like shown in the links above) The next step was to blow the "rupture discs", which had been placed to avoid the legs of the jacket filling prematurely. This failed since the compressor to be used had been damaged in transport.

    After some inovative thinking we managed to blow 7 of the discs, but not the last 4.
    Meanwhile the weather deteriorated. It was necessary to get the jacket upended quickly by filling water "from the top" with hoses, which worked.

    By 0900 hrs. Saturday, 13 March the weather had deteriorated to where we could not be positioned over the Template on the bottom due to heave.
    The jacket was now upright and stable as long as it was kept at a certian depth. We secured the jacket to the stern of HD 2500 at a hook load of only 600 - 650 m.t or so to wait for another lull, which was expected within 18-24 hrs.

    But at 1225 hrs. the Crane operator descided to lower the jacket to get his people off, without telling anybody, which resulted in the jacket becoming unstable.
    I don't know if this comes out visible, but here is a short video of a 5000 m.t. jacket doing a bit of a dance at the stern of HD 2500:


    When the Crane Operator noticed tension increase to over 1,200 m.t. he left the crane and refused to go back up. Another Crane Operator evetually manage to lower the jacket to a stable position at around 650 m.t hook load.

    It was decides to lower the jacket back to afloat position, maintaining the slings attached, with t2 tugs holding the jacket in position, away from the HD 2500.:

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