4.3
Transverse loading and overlapping effects
In many of these cases, experts were repeatedly able to detect unhooked automatic twist locks of various systems during the subsequent investigations of the cases. These systems are not fundamentally called into question here. Nevertheless, it is striking that it is evidently not possible for such systems which are responsible for the securing of container layers above the lashing bars to offer absolutely reliable protection against unintentional unlocking. Looking at such systems impartially, one can see that when a container is set down or removed, a certain rotation of the container around the vertical axis is necessary.
Of course, this is not to say that specific rotational movements impact only a single container. However, when a ship is rolling in the swell, other forces are also acting which place the connection between the containers under stress.
stack. The transversal acceleration forces are also obviously acting. At the same time, however, vertical forces may also be impacting. If we consider these forces in combination on only one end of a container, the releasing of the twist locks is not only conceivable in practice, but also measurable.
Proof for this is provided by the practical cases.
4.4
Additional vertical loads in combination with
transverse accelerations
In many publications, vertical accelerations are not considered simultaneously with rolling movements. Historically, this is understandable, as the vessels had a small width and thus a vertical heave effect on the maximum width was negligible compared to the rolling movements.
However, the assumption that a container must be twisted slightly in order to unlock it completely is too complex. The problem for the vessel’s command does not begin when the containers are completely unlocked but rather it starts when only one side, i.e., the front or the rear of the container unlocks, and such cases can occur much more easily, namely when transverse and vertical forces act simultaneously.
For example, quite simply, static downhill forces act transversely on the inclined side of a tilted container
In many publications, vertical accelerations are not considered simultaneously with rolling movements. Historically, this is understandable, as the vessels had a small width and thus a vertical heave effect on the maximum width was negligible compared to the rolling movements.
In many publications, vertical accelerations are not considered simultaneously with rolling movements. Historically, this is understandable, as the vessels had a small width and thus a vertical heave effect on the maximum width was negligible compared to the rolling movements.
However, with vessels becoming increasingly bigger, one could argue that this approach is outdated. As can be seen from diagram A, the difference in height is not particularly large for a narrow vessel. With a wider vessel, however, there is sometimes a considerable difference in height.
The difference in height illustrated in Diagram A below is now so great that it may no longer be considered insignificant or be ignored.
Actually, these circumstances are not surprising because today’s large container vessels have a width that already exceeds the length of many small vessels.
As can be seen from the diagram on the left, the difference in height is not particularly large for a narrow vessel.
Diagram A
However, with vessels becoming increasingly bigger, one could argue that this approach is outdated.
Diagram B
However, with vessels becoming increasingly bigger, one could argue that this approach is outdated.
5
Are the high towers on deck which are basically standard still generally stable at all?
Overall, the development of containers stowed on deck is to be considered. Whereas in 2000 there were often only about 6 layers on deck, today there are stacks consisting of 11 container layers. In the case of the ONE Aquila, there were photographs in the press which showed that 7 layers were stowed above the lashing rods alone.
5. Are the high towers on deck which ar all?
Considering a container stack (with 7 layers) independently of the situation on deck, one easily notices two things.
The stack on diagram B below consists of 7 layers:
4.4.4.4. Additional vertical loads in combination with transverse accelerations Additional vertical loads in combination with transverse accelerations
Overall, the development of containers in 2000 there were often only about consisting of 11 container layers. In photographs in the press which showed rods alone.
The stack shown here consists of 7 layers:
The individual containers are standard containers, i.e. no high cubes.
The centre of gravity within each container is assumed to be only 25% within each container.
Considering a container stack (with 7 la one easily notices two things.
This “stack” of a given height would tip over at a certain angle of inclination. In this case, that is only 7.8°.
The only securing counteracting this is the securing of the base of the stack.
The stack
The indiv no high c
As can be seen from the diagram on the left, the difference in height is not particularly large for a narrow vessel.
With a wider vessel, how- ever, there is sometimes a considerable difference in height.
As can be seen from the diagram on the left, the difference in height is not particularly large for a narrow vessel.
With a wider vessel, however, there is sometimes a considerable difference in height
With a wider vessel, however, there is sometimes a considerable difference in height
The Report • June 2021 • Issue 96 | 57 The difference in height illustrated above is now so great that it may no longer The difference in height illustrated above is now so great that it may no longer
The cent assumed
This "sta certain a 7.8°.
The only the base
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