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    I wonder what could cause her to capsize. Sudden maneuver, shifting cargo?

    I can only hope that the two missing crew are found at a pub nearby getting warm and having a stiff drink to calm their nerves.

    Comment


      The ships name is "Waldhof". She is loaded with sulfuric acid, which will be, if the sip leaks, very fast thinned with the Rhine water. Since this is the fluid which is also in car batteries, there seems to be no great danger. The crew members however, seem to be either inside the ship (and under water) or swalled away in the river. There is nearly no hope for them. Today they try to scan the ship with sonar sensors. It was the steerman and one of the captains.

      Nobody can imagine, how this could happen. Other captains told, this would be possible if you have stones or gravel as cargo, but not with fluid. It was night, nobody saw anything, but suddenly she dissapeared from the radar in Oberwesel. I showed you exactly this passage in my Rhine Valley thread:

      http://www.captainsvoyage-forum.com/...ey-and-Loreley
      Lofoten '07 ...... Nordnorge '11

      Comment


        Originally posted by Ralf__ View Post
        Nobody can imagine, how this could happen. Other captains told, this would be possible if you have stones or gravel as cargo, but not with fluid. It was night, nobody saw anything, but suddenly she dissapeared from the radar in Oberwesel.
        Here is the MSDS for Sulphuric Acid:
        Physical data
        Appearance: Colourless oily liquid
        Melting point: -2 C
        Boiling point: 327 C
        Specific gravity: 1.84
        Vapour pressure: <0.3 mm Hg at 20 C (vapour density 3.4)
        Flash point:
        Explosion limits:
        Autoignition temperature:
        Water solubility: miscible in all proportions
        As can be seen it is quite heavy. It is therefore likely that she was loaded to the maximum in weight, but not in volume, which means that not all tanks would have been full.

        If too many tanks were slack this could cause instability, and eventually capsizing, especially in vessels with low freeboard, like an inland tanker.
        I obviously don't know the tank arrangement, nor how the cargo was carried in this case, so this is general information only.

        Comment


          This might be an explanation.

          Here is the technical data:

          EU Nr. 04607590
          Length 110,00 m.
          Wide 10,50 m.
          Tonnage 2426 t.

          Build 1993 at Damen Shipsyard, Hardinxveld, NL for Euromar BV Zwijndrecht.
          Lenghened and modernised 2004, new Owner Lehnkering Rheinfracht GmbH, Mannheim.

          Was coming from BASF Ludwigshafen and heading for Antwerp.

          Specialists said some minutes ago, that i might be possible to turn her back again.
          But they are also waiting for more water during the next hours due to the heavy rain of the last weeks and the melting snow.
          Lofoten '07 ...... Nordnorge '11

          Comment


            Would tanks on such a boat have baffles to prevent sloshing or is each tank small enough that it is always full or empty, never half full?

            Comment


              Originally posted by pilotdane View Post
              Would tanks on such a boat have baffles to prevent sloshing or is each tank small enough that it is always full or empty, never half full?
              Sloshing is not a problem on inland vessels as they don't roll much. Baffles doesn't do anything to reduce free surface effect. If the vessel lists for a period of time the surface of the liquid will fairly quickly equalize, causing the COG to move towards the low side.

              As I said in my earlier post;
              If too many tanks were slack this could cause instability, and eventually capsizing, especially in vessels with low freeboard, like an inland tanker.
              I obviously don't know the tank arrangement, nor how the cargo was carried in this case, so this is general information only.
              I notice that this particular tanker has been lengthen and has a very high Length/Width ratio. (Loa 110 m. Width 10.5 m.) which is inherent in this type of vessels. Combined with low freeboard it is one of the reasons why the are not suited for open waters.

              How to solve the problem of loading heavy cargo in a long vessel, without exceeding the allowed bending moment??

              The nearest for comparison that comes to mind is large Bulk Carriers loading Iron Ore.
              A Capesize vessel (Say 150,000 DWT) with 9 Holds would normally be strengthen to load cargo in alternate Holds, (I.e #1, 3, 5, 7 & 9) and leave the other Holds empty.

              Some inland tankers has a centre bulkhead dividing the tank section longitudinally.
              If so, the way to load heavy liquids (Sp.g. 1.84) would be to leave alternate wing tanks empty on either side and to have the other tanks 95% full. This would reduce both bending moment and free surface effect.

              Please note that I have no knowledge of the tank arrangement on this particular vessel, if she had a longitudinal bulkhead, or how she was loaded. This is general observations only.

              Comment


                Ombugge, what is the "bending moment". When the vessel begins to list?
                Ivy

                "To thine own self be true.......
                Thou canst not then be false to any man."

                Comment


                  Originally posted by wherrygirl View Post
                  Ombugge, what is the "bending moment". When the vessel begins to list?
                  No Bending Moment is the bending of the entire ship longitudinally, know as "Hog" and "Sag", depending on whether the bow and stern is high or low relative to the middle. Some tankers used to deliberately "hog" the ship to keep the loadline mark above water line in the "good old days".

                  It is possible to break a ship by wrong distribution of the cargo. It has even happened in port, while loading or discharging.
                  For long vessels, like inland barges, it is one of the aspects to watch when deciding on how to distribute heavy cargo.

                  Comment


                    Four cranes from Duisburg and Rotterdam are ready to head for the accident. They have to wait for the flood getting lower to pass a certain bridge.
                    Lofoten '07 ...... Nordnorge '11

                    Comment


                      Uhm-mm, so it really means bending. Thamnks, Ombugge.
                      Ivy

                      "To thine own self be true.......
                      Thou canst not then be false to any man."

                      Comment


                        Hog and sag and wrong way to discharge a VLCC.

                        The following link shows what happens when a VLCC (Very Large Crude Carrier) is
                        discharged in a wrong way.

                        btw: I have done two 6 month periods as 2nd mate on this one.
                        Then named the "Golar Betty", before being sold to Hong Kong.

                        http://www.aukevisser.nl/supertankers/part-1/id417.htm

                        Comment


                          Thank you Ombugge for the education.

                          Comment


                            Originally posted by Nichu View Post
                            The following link shows what happens when a VLCC (Very Large Crude Carrier) is
                            discharged in a wrong way.

                            btw: I have done two 6 month periods as 2nd mate on this one.
                            Then named the "Golar Betty", before being sold to Hong Kong.
                            That is a very good illustration of "Hogging". This was one incident I was alluding to in post #204. (There have been others)
                            Even in the picture with the title; "in better time", she appears to be badly hogged.

                            PS> Hog/Sag has nothing to do with the capsize inland barge, unless they decided to mitigate excessive Bending Moment by part-loading all/too many tanks, thus creating excessive Free Surface Effect.

                            Comment


                              Ignoramus back again.
                              Thank you very much, Nichu, for the URL, the photos were illuminating and incredible, and Ombugge for your careful explanation.
                              If anyone has the patience to explain further, I don't understand why a ship bends instead of just sinking. Is it a simple matter of the air spaces in the parts of the ship not storing cargo that result in buoyancy of those parts against the weight of the cargo areas? I just find it incredible that considering the massive structure of ships of this size they could be - relatively speaking - so frail.
                              If I sail a long rubber (bendable!) boat in my bath and overload it with marbles in the middle, wouldn't it just sink? Ditto overloaded at both ends. Mind you, I've never tried it. . Perhaps it would bend - anyone got a spare rubber boat?
                              Ivy

                              "To thine own self be true.......
                              Thou canst not then be false to any man."

                              Comment


                                Whether an object will float or sink is defined by old Archimedes' principle.

                                It is not possible to sink a tanker like this by loading normal crude oil.
                                The tanks will overflow before the critical weight is reached.

                                On this class of tankers, the cargo area is divided into 18 tanks.
                                Three sideways, and 6 lengthwise, but of slightly different capacity.

                                The loading is accurately planned to minimize the stress on the hull.
                                Normally just 2 -3 tanks are being filled/discharged simultaneously to have control of trim and list.
                                Sometimes complicated by having more than one type of oil - not to be mixed.
                                Nearing the end of the discharge, ballast water is filled into some of the empty tanks.

                                In the Europort incident, the middle group of tanks must have been discharged
                                - out of the normal sequence.

                                When normally operated, a ship like this is solid, but also quite flexible.
                                In rough seas and fully loaded one can see the ship hog and sag with the bare eye.

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