The largest anchors ever - Vryhof

1 Anchounter 42 April2007A MEETINGGROUND FORANCHORAND MOORINGNEWSPUBLISHEDBY VRYHOFANCHORSTHIS ISSUE SUBSEA TENSIONING DRAG EMBEDDED PLATE anchors INTERMOOR FOURCHON FACILITY API RECOMMENDATIONThe 75 tons anchors are the biggestin Vryhof history and believed thebiggest in the offshore did produce a 65 ton StevprisMk3 in the 1980s and later even a 60ton Stevshark was built, however thecurrent ones include 15 tons ofballast and are thus actually 75 tons. With records like this, normally oneuses superlatives, compare it to thesize or weight of the Eiffel like that. Well, to speak inaviator terms, the anchors wing spanis 12 meters (that s one heck of astretched limo) or their weight equals35 American cars.

2 Vryhof anchors long standing clientRasmussen Equipment Co. located inSeattle Washington (USA), was todeliver the anchors to MansonConstruction Company Inc. a US-based international contractor activein offshore, dredging, bridge buildingetc. Manson s client was the BoeingCompany of America, which needs nointroduction, whose client was MDAto moor their new SBX. Transport of the anchors was to govia the Panama Canal, then right upto Seattle not exactly your averageoffshore destination. From there theywere to load out for the second legof their travels to on next pageTThhee llaarrggeesstt aanncchhoorrss eevveerr !! In january 2007 Vryhof loaded out 8 huge 75 ton Stevshark anchors from themanufacturing plant in Rotterdam, readying them for a very, very long haulthrough the Panama Canal to their final destination in Alaska.

3 Eh .. Alaska?Are offshore developments speeding up such that they need anchors ? No, notto worry you are not missing a boat; this simply concerns a secret mission. Booth 23315007 Anchounter #42 25-04-2007 12:15 Pagina 2 MDA, SBX, VA STK 75 T. Thisstarts to sound like a JamesBond Movie. Well, partlythat fits. The anchors are to become part of theInternational Missile DefenseSystems, or more precise tomoor a Sea-Based does make an interestingcombination, where themost hyper-tech industrychooses the most traditionalhigh-tech way of mooringsystem around. anchors . Transporting SBX anchors If you have transportedanchors as often as we have, you might call it aroutine operation.

4 , says BGTT ransport Director HansVerrijp when he criticallyfollows the load out of theSBX anchors in and BGT Transport goback a long way and havetransported anchors overroad, rail, through mountainspasses (more than just once!)by airplane,helicopter andyes also overwater. Someanchors aremore difficultthan not so much becauseof s not forgetthat transportation efficiencyis nowadays one of the designcriteria. We learned of the record sizeanchors last October and weregiven a time window of early2007 delivery , says Hans andwe can normally live with a timewindow like that. Generally westart setting off the possible wayof transport against the cost, arather important driver.

5 In thiscase the dimensions more thanthe weight were criteria thatlimit the choices, so that wecould not transport over roadand then the destination,Seattle, doesn t leave very manyvariations either. It s one straightline to Panama, followed by astraight line up North. I mean,no real use into looking atcrossing Canada is there? As it turned out there was onlyone liner available for that routeso we did secure a quote in timeto assure the client we wouldget his anchors to Seattle. Whenwe later specified the loads; 8flukes of 40,8 tons and 8 shanksof tons and they looked atthe dimensions, sure enoughthey suddenly discovered theycould not take it on the shipthey had offered.

6 Capacityproblems do not leave muchspace for negotiating .. grinsHans so that we had to becreative and after a while settledfor two different calls of thevessel to Vlissingen (Flushing)harbour in the South West ofHolland. On January 15, just before theload out was to commence, twoanchors were assembled on thequay side for the shooting ofsome commemorative photoswith the client reps present andthe fabrication plant staff on thephoto too! The second load left29th of January and all weretransferred to the ocean liner onFebruary 7 with ETA in Seattleon March trip is via Mazanillo,Panama Canal, Topolobambo,Los Angeles, Oakland, SanFrancisco, Vancouver and then afree out delivery in delay occurred during thefirst leg but all is set for a 22 March the secrecy Hans?

7 Vryhofdid explain about that and we stuck to it. And now wereceive reports on the vessel swhereabouts on a daily basis. RotterdamPanamaLos AngelosSeattle5007 Anchounter #42 25-04-2007 12:15 Pagina 3 ANCHOUNTER 42 Photo: anchor manufacturingplant crew, Vryhof staff and client representatives at a shortcommemorative photo shoot. 5007 Anchounter #42 25-04-2007 12:15 Pagina 4 The proof testing ofinstalled anchor points for permanently mooredfacilities such as CALM buoys and FPSOs is a criticalaspect of the overallcertification and approvalprocess for these drag embedment anchorsolutions, the proof testincludes setting the anchorsinto the seabed andensuring they do not dragbeyond allowable vertically installedanchor points are involved,such as driven piles orsuction anchors , the prooftest performs the dual roleof not only verifying theanchor point capability butof also embedding themooring line at the pile intothe seabed in a characteristicinverse catenary curve.

8 Theloads required are oftenhigh, typically being 80% ofthe maximum intact designload, and the hold period forthe proof test is dictated byclass society rules, rangingfrom 15-30 StevtensionerApplying these (substantiallyhorizontal) proof loads inthe field requires highbollard pull vessels, or bymeans of cross-tensioning ondeck using a crane, fixedwinch or chain jack , subsea tensioningcan offer significant timeand cost benefits andreduced risk over otherconventional mooring systemproof testing methods, usinga device like the VryhofStevtensioner. This is basicallya chain shortening clutch,which passes chain throughit in the slack condition butlocks onto the chain underload.

9 An anchor line isattached to one side of theStevtensioner, an opposedanchor line is passedthrough it and up to thesurface. A vertical pull onthis riser induces more thandouble that pull in thehorizontal legs, just like abowstring. The BenefitsThe potential benefits of subsea tensioning are numerous, particularlysaving time and moneyduring installation. It can be applied to all types of mooring systems andanchors provided a workingchain section is included, inshallow or deep waters. Insymmetrical systems anchorscan be cross-tensioned as opposed pairs, halving the number of tensioningoperations required, orindividual anchors can betensioned using a temporaryreaction anchor .

10 The loadsseen at the installation vesselare reduced, reducing thesize of equipment requiredand more importantlylowering risk to equipmentand personnel. The reducedrequired vertical pull enablesa wider range of vessels tobe considered for tensioningoperations, and obviates theneed for bollard pull orcrane capacity in excess ofrequired installation tensioning can beperformed from anchorhandling vessels or modestcrane barges, helping toSubsea Tensioning for Cost-Effective Installation5007 Anchounter #42 25-04-2007 12:15 Pagina 5 ANCHOUNTER 42reduce overall installationcost. The load in thehorizontal anchor leg canbe measured at theStevtensioner by means ofan integral load cell andthe data recorded in realtime on deck via anumbilical cable or acousticmodem in deeper waterdepths.