tag:theconversation.com,2011:/id/topics/marine-salvage-7167/articlesMarine salvage – The Conversation2021-03-26T19:22:22Ztag:theconversation.com,2011:article/1580062021-03-26T19:22:22Z2021-03-26T19:22:22ZSuez Canal blockage: what it takes to unwedge a megaship<figure><img src="https://images.theconversation.com/files/392020/original/file-20210326-21-1x8nisa.jpeg?ixlib=rb-1.1.0&rect=309%2C535%2C4387%2C2281&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.suezcanal.gov.eg/English/MediaCenter/News/Pages/Navigation_new25-03-2021.aspx">Suez Canal Authority</a></span></figcaption></figure><p>One of the world’s largest container ships, named Ever Given, has been wedged across the Suez Canal since it was blown off course by high winds in the early hours of March 23, blocking one of the <a href="https://theconversation.com/suez-canal-container-ship-accident-is-a-worst-case-scenario-for-global-trade-157802">busiest maritime trade corridors</a> in the world. </p>
<p>The incident has created a <a href="https://www.bbc.co.uk/news/world-middle-east-56538653">logjam</a> of hundreds of tankers, the operators of which are now weighing up whether to wait for the stranded container ship to be cleared, or whether <a href="https://www.businessinsider.com.au/suez-canal-some-consider-detour-round-africa-as-ship-blocks-way-2021-3">rerouting around the Cape of Good Hope</a>, at the southernmost point of Africa, will hasten their arrival at port.</p>
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<p>That decision hinges upon how long it’ll take to refloat the Ever Given, tugging it away from the banks of the canal and back into operation. Several maritime salvage firms, with experience rescuing stricken vessels, are already in attendance at the scene – but it’s unclear how much time they’ll need to dislodge the ship.</p>
<p>The methods they’ll use to do so, however, will be the roughly the same as past examples. A grounded ship of any size requires additional buoyancy to help salvage crews ease it from where it’s stuck. And, in the case of the Ever Given, horizontal force – applied by tug boats – will be required to heave the ship from both banks of the Suez Canal. </p>
<h2>How it happened</h2>
<p>The <a href="https://www.vesselfinder.com/vessels/EVER-GIVEN-IMO-9811000-MMSI-353136000">Ever Given</a> is 400 metres in length and has the capacity to carry over 20,000 20-foot containers. It was these containers, stacked high on the deck, that are suspected to have caught the gust of wind, like a sailboat’s sail, that ultimately blew the ship off course.</p>
<p>It appears that the Ever Given lost control while heading northbound along the Suez Canal, diverting its course in such a way that one end struck one of the canal’s banks. The momentum of the massive vessel will then have pulled it round until the other end struck the other bank – slowly, perhaps, but with a huge amount of force.</p>
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<figcaption><span class="caption">The wedged vessel has been compared to a ‘beached whale’.</span></figcaption>
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<p>The precise way in which the Ever Given struck ground will be important for salvage teams to understand because, when refloating a grounded ship, it’s usually easiest to extract it the way it went in – as with a splinter. </p>
<h2>Salvaging ships</h2>
<p>Salvaging has always been an important part of maritime operations, with specialist companies called in when large container ships or tankers run aground. The process of freeing grounded vessels is often referred to as <a href="https://www.scientific.net/AMR.837.792">refloating</a>.</p>
<p>In 2016, a ship of similar size to the Ever Given, called the <a href="https://www.offshore-energy.biz/rescue-teams-start-removing-oil-from-grounded-cscl-indian-ocean/">CSCL Indian Ocean</a>, took six days to refloat after grounding on the bank of the Elbe River in Germany. The same salvage techniques used then will be used this time around – albeit in the more restrictive environment of a narrow canal. </p>
<p>There are two basic approaches to extracting a grounded ship. First, salvage crews will work to increase the vessel’s vertical buoyancy force, which means the whole boat floats higher in the water. </p>
<p>Second, tug boats will apply sufficient horizontal force to overcome the <a href="https://core.ac.uk/download/pdf/13745437.pdf">static friction</a> generated by whatever material the boat is resting upon. The larger and heavier the vessel, the more force required by the tug boats to refloat the ship.</p>
<h2>Fleets of tugs</h2>
<p>Swiftest to mobilise are a fleet of tugs, eight of which are already in position at the site of the stranded ship. But reports from the scene suggest that tugs have already attempted an unsuccessful operation to unwedge the ship. </p>
<p>That means the first priority of salvage teams will instead be to <a href="https://www.bbc.co.uk/news/56523659">make the Ever Given float higher</a> in the water – by dredging near the sections of the bank upon which the ship is stranded, and by increasing the ship’s buoyancy. </p>
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<span class="caption">An early attempt to free the Ever Given.</span>
<span class="attribution"><a class="source" href="https://www.suezcanal.gov.eg/English/MediaCenter/News/Pages/Navigation_new25-03-2021.aspx">Suez Canal Authority</a></span>
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<p>In previous salvage operations, <a href="https://asmedigitalcollection.asme.org/OMAE/proceedings-abstract/OMAE2009/43444/571/336947">buoyancy air bags</a> have been attached to the underwater section of the hull to encourage it to float. But in the case of the Ever Given, this will need to happen alongside the unloading of the ship’s cargo, the removing of all on-board ballast water, and the draining of the ship’s fuel, all in an effort to make the vessel lighter and more buoyant before the tugs attempt another horizontal pull.</p>
<p>The removal of cargo will be particularly challenging in this case. Seeing as land access will be difficult due to the Suez Canal’s sandy surrounds, a floating crane may be required, which will take time to transport to the ship and which will only be able to remove one container at a time. </p>
<p>It might prove quicker to pump the fuel off the vessel instead of removing containers, which would require a small refuelling vessel to pull alongside to take on the fuel. Those overseeing the salvage will have access to <a href="https://en.cnki.com.cn/Article_en/CJFDTotal-WHZC201704041.htm">computer models</a> of the vessel to tell exactly which load-lightening strategy will be most effective.</p>
<h2>High tide</h2>
<p>Despite all these measures, increasing buoyancy during salvage usually relies on a rising tide, which provides an extra boost in sea level for the ship to potentially refloat upon. Unfortunately, the <a href="https://www.sciencedirect.com/science/article/pii/S0272771496901602">tidal range</a> within the Suez Canal is limited compared to coastal waters, which will hamper refloating attempts – though a promising “spring tide”, which is higher than the usual high tide, is due over the weekend.</p>
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<figcaption><span class="caption">SMIT Salvage, a Dutch maritime salvage firm, has experience ‘refloating’ large vessels that have run aground.</span></figcaption>
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<p>It’s difficult to predict the rapidity with which the various components of the salvage puzzle can be brought to bear in the Suez Canal. This is not a standard salvage operation: the time pressure, with ships queuing at either end of the strait, will be weighing on everyone’s minds.</p>
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Read more:
<a href="https://theconversation.com/suez-canal-container-ship-accident-is-a-worst-case-scenario-for-global-trade-157802">Suez Canal container ship accident is a worst-case scenario for global trade</a>
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<p>But with expert salvage crews now on hand, and tried-and-tested refloating methods being put in place around the Ever Given, it’s likely to be only a matter of days – rather than weeks – before the ship is unwedged from the Suez Canal.</p><img src="https://counter.theconversation.com/content/158006/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Stephen Turnock does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Maritime salvage experts will use a variety of techniques to free the Ever Given from the Suez Canal.Stephen Turnock, Professor of Maritime Fluid Dynamics, University of SouthamptonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/954922018-04-26T10:04:12Z2018-04-26T10:04:12ZSunken Nazi U-boat discovered: why archaeologists like me should leave it on the seabed<figure><img src="https://images.theconversation.com/files/216275/original/file-20180425-175054-1jvt9dj.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C960%2C617&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Sea War Museum</span></span></figcaption></figure><p>The collapsing Nazi government ordered all U-boats in German ports to make their way to their bases in Norway on May 2, 1945. Two days later, the recently commissioned U-3523 joined the mission as one of the most advanced boats in the fleet. But to reach their destination, the submarines had to pass through the bottleneck of the Skagerrak – the strait between Norway and Denmark – and the UK’s Royal Air Force was waiting for them. <a href="https://books.google.co.uk/books?id=zrJGDwAAQBAJ&pg=PA158&lpg=PA158&dq=raf+u-boats+Skagerrak+may+1945&source=bl&ots=-_A8eDDtEV&sig=voOvDOs_VpY2-q_bk7R27Ptw39Y&hl=en&sa=X&ved=2ahUKEwjpraDx_NTaAhXKC8AKHb1iCcw4ChDoATABegQIABAy#v=onepage&q=raf%20u-boats%20Skagerrak%20may%201945&f=false">Several U-boats were sunk</a> and U-3523 was destroyed in an air attack by a Liberator bomber.</p>
<p>U-3523 lay undiscovered on the seabed for over 70 years until it was <a href="https://www.seawarmuseum.dk/en">recently located</a> by surveyors from the Sea War Museum in Denmark. Studying the vessel will be of immense interest to professional and amateur historians alike, not least as a way of finally putting to rest the conspiracy theory that the boat was <a href="https://www.independent.co.uk/news/world/europe/hitler-nazis-u-boat-escape-argentina-u3523-found-wreck-denmark-south-america-mengele-eichmann-a8312581.html">ferrying prominent Nazis to Argentina</a>. But sadly, recovering U-3523 is not a realistic proposition. The main challenges with such wrecks lie in accurately identifying them, assessing their status as naval graves and protecting them for the future.</p>
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<p>U-boat wrecks like these from the end of World War II are the hardest to match to historical records. The otherwise meticulous record keeping of the Kriegsmarine (Nazi navy) became progressively sparser, breaking down completely in the last few weeks of the war. But Allied records have helped determine that this newly discovered wreck is indeed U-3523. The sea where this U-boat was located was heavily targeted by the RAF because it knew newly-built boats would flee to Norway this way.</p>
<h2>Identification</h2>
<p>The detailed sonar scans of the wreck site show that it is without doubt a Type XXI U-boat, of which U-3523 was the only one lost in the Skagerrak and unaccounted for. These were new types of submarines that contained a <a href="https://www.militaryfactory.com/ships/detail.asp?ship_id=Type-XXI-Uboat">number of innovations</a> which had the potential to make them dangerous opponents. This was primarily due to enlarged batteries, coupled to a snorkel, which meant they could stay permanently underwater. Part of the RAF’s mission was to prevent any of these new vessels getting to sea to sink Allied ships, and it successfully prevented any Type XXI U-boats from doing so.</p>
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<span class="caption">The Type XXI U-3008.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Type_XXI_submarine#/media/File:U3008.jpg">Wikipedia</a></span>
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<p>With the U-boat’s identity correctly established, we now know that it is the grave site of its crew of 58 German servicemen. As such, the wreck should either be left in peace or, more implausibly, recovered and the men buried on land. Germany lost <a href="https://www.routledge.com/The-Maritime-Archaeology-of-a-Modern-Conflict-Comparing-the-Archaeology/McCartney/p/book/9781138814356">over 800 submarines</a> at sea during the two world wars and many have been found in recent years. It is hopelessly impractical to recover them all, so leaving them where they are is the only real option.</p>
<p>Under international law all naval wrecks are termed “<a href="https://repository.law.miami.edu/cgi/viewcontent.cgi?article=1224&context=umialr">sovereign immune</a>”, which means they will always be the property of the German state despite lying in Danish waters. But Denmark has a duty to protect the wreck, especially if Germany asks it to do so.</p>
<h2>Protection</h2>
<p>Hundreds of wartime wreck sites such as U-3523 are under threat around the world from metal thieves and grave robbers. The British cruiser HMS Exeter, which was sunk in the Java Sea on May 1, 1942, has been <a href="https://www.theguardian.com/world/2016/nov/16/british-second-world-war-ships-illegal-scavenging-java-sea">entirely removed</a> from the seabed for scrap. And wrecks from the 1916 Battle of Jutland that also lie partly in Danish waters have seen <a href="https://www.theguardian.com/world/2016/sep/18/battle-jutland-war-graves-hms-warrior-metal-scavengers-royal-navy">industrial levels of metal theft</a>. These examples serve as a warning that organised criminals will target shipwrecks of any age for the metals they contain.</p>
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<span class="caption">Detailed sonar scans have been taken.</span>
<span class="attribution"><span class="source">Sea War Museum</span></span>
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<p>Germany and <a href="https://www.royalnavy.mod.uk/news-and-latest-activity/news/2017/december/21/171221-hi-tech-spy-tech-harnessed-to-protect-shipwrecks">the UK</a> are among a number of countries currently pioneering the use of satellite monitoring to detect suspicious activity on shipwrecks thought to be under threat. This kind of monitoring could be a cost-effective way to save underwater cultural heritage from criminal activity and its use is likely to become widespread in the next few years.</p>
<h2>Recovery</h2>
<p>The recovery cost is only a small fraction of the funds needed to preserve and display an iron object that has been immersed in the sea for many years. So bringing a wreck back to the surface should not be undertaken lightly. In nearly all cases of salvaged U-boats, the results have been financially ruinous. Lifting barges that can raise shipwrecks using large cranes cost tens of thousands of pounds a day to charter. Once recovered, the costs of conservation and presentation mount astronomically as the boat will rapidly start to rust.</p>
<p>The U-boat U-534 was also sunk by the RAF in 1945, close to where U-3523 now lies. Its crew all evacuated that boat, meaning that she was not a grave when recovered from the sea in 1993 by Danish businessman Karsten Ree, allegedly in the somewhat incredible belief that it carried Nazi treasure. At a <a href="https://www.independent.co.uk/news/world/europe/u-boat-holds-on-to-secrets-as-opening-is-delayed-discovery-of-vintage-wine-on-wartime-german-1463295.html">reported cost of £3m</a>, the operation is thought to have been unprofitable. The boat contained nothing special, just the usual mundane objects carried on a U-boat at war.</p>
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<span class="caption">U-534 after the rescue.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/127799425@N07/22986280556">Les Pickstock/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<p>Similar problems were experienced by the Royal Navy Submarine Museum in the UK when it raised the Holland 1 submarine in 1982. In that case, the costs of <a href="https://www.researchgate.net/publication/303674154_ELECTROCHEMICAL_AND_PHYSICAL_TECHNIQUES_IN_SUPPORT_OF_THE_CONSERVATION_OF_HISTORIC_VESSELS_IN_THE_SOLENT">long-term preservation</a> proved much greater than anticipated after the initial rust-prevention treatment failed to stop the boat corroding. It had to be placed in a sealed tank full of alkali sodium carbonate solution for four years until the corrosive chloride ions had been removed, and was then transferred to a purpose-built exhibition building to protect it further.</p>
<p>The expensive process of raising more sunken submarines will add little to our knowledge of life at sea during World War II. But each time a U-boat is found, it places one more jigsaw piece in its correct place, giving us a clearer picture of the history of the U-boat wars. This is the true purpose of archaeology.</p><img src="https://counter.theconversation.com/content/95492/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span><a href="mailto:imccartney@bournemouth.ac.uk">imccartney@bournemouth.ac.uk</a> receives funding from The Leverhulme Trust
</span></em></p>Raising U-3523 wouldn’t be worth the incredible cost.Innes McCartney, Leverhulme Early Career Fellow, Department of Archaeology, Anthropology and Forensic Science, Bournemouth UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/799242017-06-25T20:05:25Z2017-06-25T20:05:25ZSludge, snags, and surreal animals: life aboard a voyage to study the abyss<figure><img src="https://images.theconversation.com/files/175349/original/file-20170623-29738-17uu1u7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The famous "faceless fish", which garnered worldwide headlines when it was collected by the expedition.</span> <span class="attribution"><span class="source">Rob Zugaro</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Over the past five weeks I led a “<a href="https://www.nespmarine.edu.au/abyss-landing-%20page">voyage of discovery</a>”. That sounds rather pretentious in the 21st century, but it’s still true. My team, aboard the CSIRO managed research vessel, the <a href="http://www.csiro.au/RV-Investigator-virtual-tour/rv_investigator.html">Investigator</a>, has mapped and sampled an area of the planet that has never been surveyed before. </p>
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<a href="https://images.theconversation.com/files/175343/original/file-20170623-27912-14vsgz7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/175343/original/file-20170623-27912-14vsgz7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/175343/original/file-20170623-27912-14vsgz7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/175343/original/file-20170623-27912-14vsgz7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/175343/original/file-20170623-27912-14vsgz7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/175343/original/file-20170623-27912-14vsgz7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/175343/original/file-20170623-27912-14vsgz7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/175343/original/file-20170623-27912-14vsgz7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The RV Investigator in port.</span>
<span class="attribution"><span class="source">Jerome Mallefet/FNRS</span></span>
</figcaption>
</figure>
<p>Bizarrely, our ship was only 100km off Australia’s east coast, in the middle of a busy shipping lane. But our focus was not on the sea surface, or on the migrating whales or skimming albatross. We were surveying The Abyss – the very bottom of the ocean some 4,000m below the waves.</p>
<p>To put that into perspective, the <a href="http://www.gnb.nsw.gov.au/place_naming/placename_search/extract?id=KWwGjzsETR">tallest mountain</a> on the Australian mainland is only 2,228m. Scuba divers are lucky to reach depths of 40m, while nuclear submarines dive to about 500m. We were aiming to put our cameras and sleds much, much deeper. Only since 2014, when the RV Investigator was commissioned, has Australia had the capacity to survey the deepest depths.</p>
<p>The months before the trip were frantic, with so much to organise: permits, freight, equipment, flights, medicals, legal agreements, safety procedures, visas, finance approvals, communication ideas, sampling strategies – all the tendrils of modern life (the thought “why am I doing this?” surfaced more than once). But remarkably, on May 15, we had 27 scientists from 14 institutions and seven countries, 11 technical specialists, and 22 crew converging on Launceston, and we were off.</p>
<h2>Rough seas</h2>
<p>Life at sea takes some adjustment. You work 12-hour shifts every day, from 2 o’clock to 2 o’clock, so it’s like suffering from jetlag. The ship was very stable, but even so the motion causes seasickness for the first few days. You sway down corridors, you have one-handed showers, and you feel as though you will be tipped out of bed. Many people go off coffee. The ship is “dry”, so there’s no well-earned beer at the end of a hard day. You wait days for bad weather to clear and then suddenly you are shovelling tonnes of mud through sieves in the middle of the night as you process samples dredged from the deep.</p>
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<figcaption>
<span class="caption">Shifting through the mud of the abyss on the back deck.</span>
<span class="attribution"><span class="source">Jerome Mallefet/FNRS</span></span>
</figcaption>
</figure>
<p>Surveying the abyss turns out to be far from easy. On our very first deployment off the eastern Tasmanian coast, our net was shredded on a rock at 2,500m, the positional beacon was lost, tens of thousands of dollars’ worth of gear gone. It was no one’s fault; the offending rock was too small to pick up on our <a href="http://mnf.csiro.au/Vessel/Investigator-2014/Equipment/Marine-acoustics-seafloor-mapping-and-fisheries-acoustics.aspx">multibeam sonar</a>. Only day 1 and a new plan was required. Talented people fixed what they could, and we moved on.</p>
<p>I was truly surprised by the ruggedness of the seafloor. From the existing maps, I was expecting a gentle slope and muddy abyssal plain. Instead, our sonar revealed canyons, ridges, cliffs and massive rock slides – amazing, but a bit of a hindrance to my naive sampling plan.</p>
<p>But soon the marine animals began to emerge from our videos and samples, which made it all worthwhile. Life started to buzz on the ship. </p>
<h2>Secrets of the deep</h2>
<p>Like many people, scientists spend most of their working lives in front of a computer screen. It is really great to get out and actually experience the real thing, to see animals we have only read about in old books. The tripod fish, the <a href="https://www.nespmarine.edu.au/faceless-fish-looks-happier-and-heartier-it-did-1887">faceless fish</a>, the shortarse feeler fish (yes, really), red spiny crabs, worms and sea stars of all shapes and sizes, as well as animals that <a href="https://www.nespmarine.edu.au/beam-us-j%C3%A9r%C3%B4me">emit light</a> to ward off predators.</p>
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<figcaption>
<span class="caption">A spiny red lithodid crab.</span>
<span class="attribution"><span class="source">Rob Zugaro/Museums Victoria</span></span>
</figcaption>
</figure>
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<figcaption>
<span class="caption">The tripod fish uses its long spines to sit on the seafloor waiting for the next meal.</span>
<span class="attribution"><span class="source">Rob Zugaro/Museums Victoria</span></span>
</figcaption>
</figure>
<p>The level of public interest has been phenomenal. You may already have seen <a href="http://www.abc.net.au/news/2017-05-30/researchers-drag-faceless-fish-up-from-the-abyss/8572634">some of the coverage</a>, which ranged from the <a href="http://www.npr.org/2017/06/15/533063615/explorers-probing-%20deep-sea-%20abyss-off-australias-coast-find-living-wonders">fascinated</a> to the amused – for some reason our discovery of <a href="http://mashable.com/2017/06/18/peanut-worm-looks-phallic/#GAkg8P.vh8qC">priapulid worms</a> was a big hit on <a href="https://www.youtube.com/watch?v=VPgVtWDljcU">US late-night television</a>. In many ways all the publicity mirrored our first reactions to animals on the ship. “What is this thing?” “How amazing!”</p>
<p>The important scientific insights will come later. It will take a year or so to process all the data and accurately identify the samples. Describing all the new species will take even longer. All of the material has been carefully preserved and will be stored in museums and CSIRO collections around Australia for centuries. </p>
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<figcaption>
<span class="caption">Scientists identifying microscopic animals onboard.</span>
<span class="attribution"><span class="source">Asher Flatt</span></span>
</figcaption>
</figure>
<p>On a voyage of discovery, video footage is not sufficient, because we don’t know the animals. The modern biologist uses high-resolution microscopes and DNA evidence to describe the new species and understand their place in the ecosystem, and that requires actual samples.</p>
<p>So why bother studying the deep sea? First, it is important to understand that humanity is already having an impact down there. The oceans are changing. There wasn’t a day at sea when we didn’t bring up some rubbish from the seafloor – cans, bottles, plastic, rope, fishing line. There is also old debris from steamships, such as unburned coal and bits of <a href="http://www.ehow.com/info_12152358_causes-clinkers-coal-fired-boilers.html">clinker</a>, which looks like melted rock, formed in the boilers. Elsewhere in the oceans there are plans to mine precious metals from the deep sea.</p>
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<figcaption>
<span class="caption">Rubbish found on the seafloor.</span>
<span class="attribution"><span class="source">Rob Zugaro/Museums Victoria</span></span>
</figcaption>
</figure>
<p>Second, Australia is the custodian of a vast amount of abyss. Our marine <a href="http://www.ga.gov.au/scientific-topics/national-location-information/dimensions/oceans-and-seas#heading-1">exclusive economic zone (EEZ)</a> is larger than the Australian landmass. The Commonwealth recently established a <a href="http://www.environment.gov.au/topics/marine/marine-reserves">network of marine reserves</a> around Australia. Just like National Parks on land, these have been established to protect biodiversity in the long term. Australia’s <a href="https://www.nespmarine.edu.au/">Marine Biodiversity Hub</a>, which provided funds for this voyage, as been established by the Commonwealth Government to conduct research in the EEZ. </p>
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<figcaption>
<span class="caption">The newly mapped East Gippsland Commonwealth Marine Reserve, showing the rugged end of the Australian continental margin as it dips to the abyssal plain. The scale shows the depth in metres.</span>
<span class="attribution"><span class="source">Amy Nau/CSIRO</span></span>
</figcaption>
</figure>
<p>Our voyage mapped some of the marine reserves for the first time. Unlike parks on land, the reserves are not easy to visit. It was our aim to bring the animals of the Australian Abyss into public view.</p>
<p>We discovered that life in the deep sea is diverse and fascinating. Would I do it again? Sure I would. After a beer.</p><img src="https://counter.theconversation.com/content/79924/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tim O'Hara receives research funding from the National Environmental Science Programme's Marine Biodiversity Hub. </span></em></p>Surveying the bottom of the ocean turns out to be far from easy. But there was something wonderful about seeing animals we have only read about in old books.Tim O'Hara, Senior Curator of Marine Invertebrates, Museums Victoria Research InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/247582014-03-25T09:50:57Z2014-03-25T09:50:57ZRecovering MH370 will be difficult in a complex, unforgiving ocean<p>It has been confirmed that the Malaysia Airlines plane that disappeared on March 8 crashed into the southern Indian Ocean. It would be hard to choose a more complicated region of the ocean to be searching for scattered aircraft debris.</p>
<p>The area of the southern Indian Ocean to which the missing Malaysia Airlines flight MH370 <a href="http://www.bbc.co.uk/news/world-asia-26716572">has been traced</a>, 1,500 miles west of Australia’s southwestern coast, lies just on the northern flank of the <a href="http://www.princeton.edu/%7Eachaney/tmve/wiki100k/docs/Antarctic_Circumpolar_Current.html">Antarctic Circumpolar Current</a>, a huge ocean current encircling Antarctica. In many ways it is similar to the <a href="http://www.metoffice.gov.uk/learning/wind/what-is-the-jet-stream">atmospheric jet stream</a>, or a series of jet streams.</p>
<h2>Rivers and currents</h2>
<p>Just as in the jet stream, the strange effect of the earth’s rotation leads to the eastward-flowing currents focusing into narrow bands, like rivers flowing within the ocean. The currents loop into closed eddies that break away from their current and spin off, like high and low pressure systems moving through the atmosphere.</p>
<p>Unlike the atmosphere, these highs and lows are on a much smaller scale, perhaps 100-500km across. Typical flow speeds are around 20cm per second – about ten miles per day – but faster speeds of up to 100cm per second are possible, and the direction of flow at any one time is very unpredictable.</p>
<p>The search area spans both the northernmost “river” of the Circumpolar Current, and a much calmer area to the north where currents are much slower. This means debris could have been scattered and pulled in different directions, at different speeds.</p>
<h2>Ill winds</h2>
<p>Further complicating things is the effect of the wind. Any floating debris will be directly pushed by the wind, but will also be surrounded by water in the <a href="http://www.britannica.com/EBchecked/topic/181652/Ekman-layer">Ekman layer</a>, which is the top 50 metres or so of the ocean in which the effect of the wind is immediately felt. </p>
<p>Here again, the rotation of the earth has an effect which results in water moving (in the southern hemisphere) to the left of the direction of the wind, to a degree which depends on depth. So the wind can cause debris to drift across the deeper ocean currents, generally to the north in this region of prevailing westerlies, but how much of an effect the wind has will depend on how deeply the debris is floating.</p>
<h2>Deep waters</h2>
<p>It is now <a href="http://www.bbc.co.uk/news/world-asia-26503141">more than two weeks</a> since flight MH370 was lost. In that time, debris could have drifted by several hundred miles from where it is presumed the plane hit the water, and the patch of debris could have spread by a substantial fraction of that distance. Even if the debris spotted is confirmed to be from the plane, finding any sunken remains will still be a big challenge.</p>
<p>The ocean in that region is about 3,500-4,000 metres deep, and finding sunken wreckage will involve combing a vast area with advanced sonar imaging technology. Then there is the challenge of reaching it: only specialised equipment can operate at the pressures of more than 350 atmospheres present at such depths, although from that point of view it could have been worse – large areas of the seafloor lie more than 5,000 metres below the surface, with a few narrow trenches beyond 10,000 metres deep.</p>
<p>If the debris is confirmed to be from the Malaysia Airlines plane, a lot of work will remain to be done. It will still be a long time before we are in a position to determine what happened to flight MH370.</p><img src="https://counter.theconversation.com/content/24758/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Chris Hughes receives NERC funding for work at the National Oceanography Centre and from the National Centre for Earth Observation for research into Southern Ocean dynamics.</span></em></p>It has been confirmed that the Malaysia Airlines plane that disappeared on March 8 crashed into the southern Indian Ocean. It would be hard to choose a more complicated region of the ocean to be searching…Chris Hughes, Professor of Sea Level Science, University of LiverpoolLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/182142013-09-16T05:37:35Z2013-09-16T05:37:35ZRighting the Costa Concordia: how to flip a half-sunk ship<figure><img src="https://images.theconversation.com/files/31330/original/br2gmv42-1379090402.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">'You take the front, I'll take the back.'</span> <span class="attribution"><span class="source">EPA/Massimo Percossi</span></span></figcaption></figure><p>The huge Costa Concordia cruiseship is due <a href="http://www.theparbucklingproject.com/">to be righted</a> in preparation for finally being towed away from the Italian island of Giglio. But why has lifting and removing the wreck taken so long, given that the accident occurred back <a href="http://www.telegraph.co.uk/news/worldnews/europe/italy/9014706/Six-dead-and-thousands-evacuated-as-cruise-ship-runs-aground-off-coast-of-Italy.html">in January 2012</a>?</p>
<p>The first thing to remember is that structurally intact floating ships are designed to move with relative ease. But they are very heavy and large. Concordia is nearly 300m long and weighs in at over 114,000 tonnes - and that’s without taking into account the fact she’s full of sea water. To put it into perspective, the ship is as long as the Eiffel Tower is high, but more than ten times heavier.</p>
<p>Working with such a massive structure as this on flat, stable ground would be difficult. On an uneven seabed in 20m of water with waves and currents it becomes almost unachievable. Adding to the complications is the huge gash on one side of the vessel, making it impossible to float Concordia again on its own, but also weakening the whole structure.</p>
<p>Consider the reasons behind the major operations that have taken place around this vessel for nearly two years. The initial priority was to save lives. The next was to protect the environment - booms were deployed around the ship to prevent oil escaping, and the fuel on board was pumped out in the first few weeks.</p>
<p>Then there is the issue of gathering evidence for legal proceedings, though in this case recovering the ship is unlikely to reveal any new evidence of any use now that <a href="http://www.bbc.co.uk/news/world-europe-23388680">five crew have been convicted</a> (though the captain has yet to come to trial). For a ship with light damage the final priority is to recover and repair the asset, and the sooner this is done the less expensive the repair. But Concordia is beyond repair, both physically and emotionally - few would want to sail on a cruise liner rebuilt marked by such tragic circumstances.</p>
<p>The focus now is to remove what is an eyesore and environmental threat for the <a href="http://www.giglioinfo.com/">island of Giglio</a> as well as a constant reminder for those who lost loved ones in this disaster. It is important but only if it can be done safely. A rushed attempt to recover the vessel is at best likely to break up the ship, making the final recovery process slower and more dangerous. At worst it could lead to further loss of life; imagine ten Eiffel Towers crashing down around you.</p>
<p>The first priority has been to stabilise the ship and support it so that it doesn’t slide into deeper water. Water depth has a major impact on the engineering around the ship, and even an additional 10m could have made the current plans unfeasible.</p>
<p>The <a href="http://www.smit.com/">salvage team</a> has had to weld huge steel sponsons - like supersized inflatable swimming armbands - onto the ship’s hull to add buoyancy. The sponsons on the raised side of the ship will first be flooded with seawater to help drag the ship from the angle at which it is lying back onto its keel, using gravity to help a system of cables pull the Concordia upright. Where the bow has been weakened by the hole in the hull, bracing has been added to prevent it shearing off - like a neck brace on a patient. Lastly, as pulling the ship upright to rest on rocky and sloping seabed would be very unstable, a level “mattress” of concrete and steel has been built underneath to provide a level surface on to which to roll the ship.</p>
<p>More than 30,000 tonnes of material (a quarter of the ship’s weight) has been used in the salvage operation, and the cost so far has been £500 million - more than Concordia cost to build. An operation of this scale takes significant time and we might equally comment on how it has been managed so quickly and efficiently, rather than how long it has taken. In the next few days, at the first sign of good weather and calm seas, the operation to right Costa will begin and take about 12 hours. Once it starts to roll a point of no return comes and the engineers will have to rely on the accuracy of their calculations.</p>
<p>As the vessel begins to right herself, material from inside the ship will spill into the sea and localised debris and pollution is likely. This will be minimised by floating booms around the vessel, but some environmental impact is inevitable. Less, of course, than leaving Concordia where she is. The first task once the vessel is upright and safely secured will be to try to locate the last two missing bodies from the wreck. This will be followed by several months of shoring up and making safe over the winter.</p>
<p>If all goes well Concordia will be towed away with the aid of the now air-filled sponsons in Spring 2014 as the weather improves. Her final fate - far less glamorous than the cruise packages she once offered - is to be broken up for scrap.</p><img src="https://counter.theconversation.com/content/18214/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Simon Boxall does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The huge Costa Concordia cruiseship is due to be righted in preparation for finally being towed away from the Italian island of Giglio. But why has lifting and removing the wreck taken so long, given that…Simon Boxall, Lecturer in Ocean and Earth Science, University of SouthamptonLicensed as Creative Commons – attribution, no derivatives.