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Container Ship Stuck In The Suez Canal OT

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  • Originally posted by darryl View Post
    ......

    Looking at it another way, perhaps the ships are the wrong shape- they should be round. No bow to dig in, no stern to catch. Make a convoy out of them- make them two miles long, doesn't matter. You can still go around corners, and if one titanics and sinks you can just let it go- you don't have to lose the whole convoy.

    Whoo hoo- my mind is razor sharp today
    Round ships have been made..... by the russians. The navy versions were not so great, but the yacht version was stable and well liked.

    You can look them up on the internet.
    2730

    Keep eye on ball.
    Hashim Khan


    It's just a box of rain, I don't know who put it there.

    Comment


    • IMO the notion some of you have that the stern would swing when the bow dug in is wrong. Have any of you actually hit something dead on in a boat? I have, lots of times! In everything from kayaks to a 30' sloop. If the bow hit, the momentum of the boat was in line with the keel, there would be no swinging action. In fact, if it's at an angle, what usually happens is the bow slides to teh side, and the stern comes in to that same shore brought by the momentum that was heading that way.
      Last edited by gellfex; 03-30-2021, 06:28 PM.
      Location: Jersey City NJ USA

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      • That assumes it's not yawing when it goes aground. And with strong prevailing winds, along with the maneuvers employed to maintain steerage, AND intermittent gusts pushing that "effective sail" broadside, that may not be a good assumption.

        It would seem that much would depend on the profile and structure of the canal bottom near the sides. I can picture the bottom of the bow area (stem) starting to drag as it first lightly encounters a sandy canal bottom, and starting to slew or yaw around, with the main momentum still carrying the ship forward.

        Think of a car hitting a guard rail at a shallow angle, with a front corner (fender or bumper.) The car will certainly turn to a more perpendicular relation to the guard rail.
        Lynn (Huntsville, AL)

        Comment


        • As far as naming the ships Ever------- there are sure some names you wouldn't use now, like 'Afloat', or 'Moving', and there might be some that would be pertinent, like 'Clear', or 'Crash' Sorry.
          I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

          Comment


          • Originally posted by gellfex View Post
            IMO the notion some of you have that the stern would swing when the bow dug in is wrong. Have any of you actually hit something dead on in a boat? I have, lots of times! In everything from kayaks to a 30' sloop. If the bow hit, the momentum of the boat was in line with the keel, there would be no swinging action. In fact, if it's at an angle, what usually happens is the bow slides to teh side, and the stern comes in to that same shore brought by the momentum that was heading that way.
            That is probably not the situation in the canal. You are describing what happens when the vessel is on a stable path.

            Here, we had a very large and heavy vessel that was proceeding at 12 to 15 knots along a fairly narrow canal. The wind definitely hit it, there is the graph of wind speed at the time of the accident to prove it.

            There was simply no space for the vessel to come to stability on a path into the bank, and even a moderately alert master would notice the new course in the time needed to come to stability on a new path. I would imagine it takes several minutes for that size of vessel to come around significantly, let alone stop slewing and come to a new stable path. (And several more to undo what was done).

            The likely precipitating issue was wind, likely combined with human factors. The wind would get the vessel at an angle, but it would be still slewing, not on a course in-line with the keel. The center of mass would be to port of the location of the bow, relative to the course at the instant of grounding (I believe it grounded the bow on the east bank of the canal). That is sufficient to swing the stern around, as apparently did in fact happen. The action is to grind the bow further into the bank, in fact.

            You can look at aerial pics of large vessels turning. They do not go around on rails, there is, as you know, a disturbed water area toward the inside of the turn, due to the hull actually sliding sideways, prior to coming to stability on the new course. Probably less so on many sailboats, due to the keel, but that ship looks more like a large canoe as to the hull form below waterline.
            Last edited by J Tiers; 03-30-2021, 08:02 PM.
            2730

            Keep eye on ball.
            Hashim Khan


            It's just a box of rain, I don't know who put it there.

            Comment


            • Originally posted by J Tiers View Post

              That is probably not the situation in the canal. You are describing what happens when the vessel is on a stable path.

              Here, we had a very large and heavy vessel that was proceeding at 12 to 15 knots along a fairly narrow canal. The wind definitely hit it, there is the graph of wind speed at the time of the accident to prove it.

              There was simply no space for the vessel to come to stability on a path into the bank, and even a moderately alert master would notice the new course in the time needed to come to stability on a new path. I would imagine it takes several minutes for that size of vessel to come around significantly, let alone stop slewing and come to a new stable path. (And several more to undo what was done).

              The likely precipitating issue was wind, likely combined with human factors. The wind would get the vessel at an angle, but it would be still slewing, not on a course in-line with the keel. The center of mass would be to port of the location of the bow, relative to the course at the instant of grounding (I believe it grounded the bow on the east bank of the canal). That is sufficient to swing the stern around, as apparently did in fact happen. The action is to grind the bow further into the bank, in fact.

              You can look at aerial pics of large vessels turning. They do not go around on rails, there is, as you know, a disturbed water area toward the inside of the turn, due to the hull actually sliding sideways, prior to coming to stability on the new course. Probably less so on many sailboats, due to the keel, but that ship looks more like a large canoe as to the hull form below waterline.
              After all my years of boating my gut says no. Leeway, the effect of the wind on a hull, is a function of both your underwater and above water profile areas. A rowboat with no appreciable hull depth skitters across the water in a wind. But a deep hulled ship does not, even if it is twice as tall as it is deep, since water is so very much denser than air and resists the force. It takes way, way more force to push a deep ship sideways than it does to push it forward in the way it was designed.

              Even if there was a gust that hit the bow and not the stern, since hitting both would cause it to slide parallel to the bank not into it, given the speed they were going at best it would alter the course, not slew the ship the way a rudder can. A rudder changes the hydrodynamics of the hull and pushes the stern in the direction opposite the turn, that's the slewing you see in a rudder turn. Its the difference between turning a car and drifting one. This would be more like giving a moving car's nose a steady nudge on a gravel track. The momentum of the car would deviate, not stay in the same direction, the car wouldn't just slide sideways the way it would on ice.
              Location: Jersey City NJ USA

              Comment


              • Im more on the lines of what JT stated --- due to the wind the boat was in a crab of sorts,,, all it would take is just a small angle and then that would get compounded with all the weight in the back of the vessel... Im sure they will have some kinda graph we can all view pretty soon like the One Mike E. posted --- maybe it will shed some light on all the speculation...

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                • I saw a video that showed the path of the ship according to the gps readout. It showed the ship veering to the right, after a drift to the left. Easily could be over correcting for movement due to wind.

                  Neither of us KNOWS what happened, my point is that there is a perfectly good scenario for the ship being steered in such a way that it was "crabbing". Whether that was due to wind, over-correction on account of wind, or what, we none of us know.
                  2730

                  Keep eye on ball.
                  Hashim Khan


                  It's just a box of rain, I don't know who put it there.

                  Comment


                  • There's so many factors to consider - that canal probably flows like a river inward from both ends at high tide and meets in the middle, if the flow rate was large enough and going with the ship the rudder would not work well and also the ship could stick it's nose at an angle and then the tail could be pushed into the other side by the flow rate along with other forces,,, ships are just as prone to "water speed" as aircraft are to airspeed or they "flounder" only difference is they don't fall out of the sky because of it...

                    Comment


                    • Time to end the speculation.... start at 7:00


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                      • AWESOME Mike, very good breakdown by an expert,

                        thing is - is that it looked like it was actually back under control - was in the middle and then a "insta twich" almost as if someone steered it directly in the wrong direction...

                        that last twitch does not make much sense as it looked "stable" but then again the previous wind graph does bring up the epic gust at last moments so maybe that's it --- ?

                        Comment


                        • After watching the video it looks to me like a hysteresis loop caused by wind and bank effect/squat.

                          Comment


                          • Originally posted by A.K. Boomer View Post
                            AWESOME Mike, very good breakdown by an expert,

                            thing is - is that it looked like it was actually back under control - was in the middle and then a "insta twich" almost as if someone steered it directly in the wrong direction...

                            that last twitch does not make much sense as it looked "stable" but then again the previous wind graph does bring up the epic gust at last moments so maybe that's it --- ?
                            The video gives that also.... (A very good and entirely sensible explanation, by the way)... once the vessel is across to any degree, between the bank suction and the wind, it would get crosswise with almost no way to escape.

                            It's interesting, very much the same thing you would expect with a current through the canal, only there isn't one, apparently. And as soon as you get the bow stuck into the bank, the current (in this case the wind) brings the stern around, helped by the sideways crabbing due to the bank effect mentioned in the video.

                            Quite sensible and as far as I can see, technically correct, stated by someone who clearly understands the subject. Thanks for posting it!


                            2730

                            Keep eye on ball.
                            Hashim Khan


                            It's just a box of rain, I don't know who put it there.

                            Comment


                            • Originally posted by J Tiers View Post

                              The video gives that also.... (A very good and entirely sensible explanation, by the way)... once the vessel is across to any degree, between the bank suction and the wind, it would get crosswise with almost no way to escape.



                              Yeah but watching the vid it seems like it was settled out in the middle of the canal -- then all the sudden went full bore into the bank... it's just kinda strange looking like orders were given to the stern man but he was standing backwards at the time and got them mixed up lol

                              Comment


                              • Great video Mike, it also shows why the stern hit the west bank, it was the wind from the south! In all the reports of wind I assumed they were from the W, explaining why it hit the east bank. But once it hit the E bank and stopped, the S wind would push the stern to the W bank, rather than the ship's momentum.
                                Location: Jersey City NJ USA

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