DK201770664A1 - A stiffness tuned container lashing rod, a container lashing system and a method of lashing containers - Google Patents

Abstract

A stiffness tuned container lashing rod configured for lashing at least one container to a container ship is disclosed. The stiffness tuned container lashing rod comprises one or more expansion sections disposed in-between a first end section and a second end section of the stiffness tuned container lashing rod. The one or more expansion sections is/are configured to be resiliently expandable, following application of tensile force to the stiffness tuned container lashing rod, by a distance which is greater than any expansion of the first end section and/or the second end section.

Description

A stiffness tuned container lashing rod, a container lashing system and a method of lashing containers

When containers are loaded on board a ship, at container positions on deck or on top of hatch covers, the containers must be secured to the ship’s structure and/or the underlying containers in order to prevent the containers from moving from their positions and, ultimately, fall off from their positions and into the sea during rough weather or heavy winds. The structure to which the containers are secured typically constitutes a lashing bridge or fixation points on ship’s primary structure provided in-between the container bays of a container ship.

A lashing bridge is a strong steel structure installed between container hatches, or cargo holds, of a container ship. Lashing bridges are installed to permit access and lashing of additional tiers or layers of containers stowed on deck, on top of hatch covers or above containers stowed in cell guides in open top cargo holds.

Securing of the containers takes place by means of lashing rods, turnbuckles and twist-locks.

A lashing rod is a loose securing device which, in conjunction with a turnbuckle, ties a corner of a container to a lashing eye provided on ship’s structure and/or the underlying containers.

A twist lock is a locking device for securing containers to each other or to means for transportation.

Within the context of this specification, the term “rod” denotes an element that supports tension and, to some extent, also compression and axial torsion. In some embodiments the rod is an essentially straight element along a longitudinal axis.

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The inventor has discovered that the upper of two lashing rods in external double lashing configurations carries significantly more load than the lower one, sometimes in the order of 80% 120%, while at the same time it is known that the lower comers, or the lower corner castings, of containers can carry or convey less horizontal pull-out loads than the upper comers. This means that the lower comers of the containers are more sensitive than the upper comers to pulling sideways in the horizontal direction, where it may tom loose from the container box. In conclusion, in the current external double lashing arrangements, the containers are susceptible to damage.

Thus todays external lashing systems are not only unbalanced, they are also completely opposite in terms of load distribution with regard to the containers capability to accept forces imposed from lashing, as it would be optimal to take up more load in the top comers of the underlying containers.

Recent insight by the inventor into the behaviour of containers lashed by means of external double lashings have shown that due to the slip inherent in the corner-to-comer connections, often facilitated by twist locks, of container stacks, the upper of the two lashing rods takes a significant part of the overall load while the strength of the lower of the two lashing rods is not fully utilized.

Moreover, topological studies of the container stack and lashing system show that the reason that the upper lashing takes much more load is that the mobility of the upper container is much higher than the mobility of the lower container due to the gaps and tolerances present in the container stack. Essentially the lock, or the twist lock, between the two containers is not stiff enough in relationship to the lashing system to allow force to propagate down to the lower container and through the lower of the two lashing rods and to the container ship.

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There are some systems in the market that targets load equalization between lashings for upper and lower containers in external double lashing configurations. In these known systems, both lashings, i.e. the upper and lower lashings, are connected to a mechanical load equalization device, or yoke. One drawback of this system is that it inherently introduces a common point of failure for both lashings. Other drawbacks of this system are that its installation requires substantial modification to already operable lashing systems and that the system, once installed, requires regular maintenance of its moving parts.

Furthermore, there are prior proposals available where balancing the loads on/from the lashings take place in the turnbuckles by means of built in springs or equivalent. These proposals do not appear to have been used nor intended for use in external double lashing of stacked containers. Instead they were marketed for use in single configurations of wind lashings.

US 2006/088394 A1 discloses a self-adjusting fastening device for securing a container to a ship. The fastening device includes shock absorbing spring means configured for absorbing shock loads imposed on the lashing gear following movement of the container.

WO 92/05049 A1 discloses a lashing device configured for lashing two containers placed on top of each other. The lashing devise comprising a yoke pivoted in a deck fastener and has two arms with one respective connection point on each arm for two mutually interacting rods. The yoke distributes the load equally onto the two interacting lashing rods.

US 2015/0360599 A1 discloses a securing assembly adapted to secure objects to a structure. The assembly includes attachment means, adapted to attach the assembly to an object in use, and an elongate rod. The first end of the rod is connectable to the attachment means and the second end of the rod connectable to adjustment means. A base is adapted to connect the

DK 2017 70664 A1 adjustment means to the structure in use and the adjustment means is operable to adjust a tension between the object and the structure to secure the object to the structure.

US 2008/213060 A1 discloses a lashing device including a stretching device to be fastened between two fixing points that are to be secured to one another; typically two containers. The stretching device includes stretching device parts which are each connectible to one of the fixing points. At least a first stretching device part has a stretching rod extending in the longitudinal direction of the stretching device and has a threaded portion. A second stretching device part supports a nut part which is to be screwed onto the thread of the first stretching device part. Between the first and the second stretching device part, a coupling part is arranged which, by snap action, allows mutual rotation of the two stretching device parts in at least a direction of rotation which corresponds to tightening of the stretching device and counteracts rotation in the opposite direction.

US 1,974,686 A discloses a lashing chain for tying containers to freight cars where the lashing includes a spring section.

JP 2006 142881 A2 discloses a container lashing including an adjusting rope configured as a loop and made from high-strength fibres.

EP 1 122 163 A1 discloses a hook fitting configured for holding a lashing rod in the corner fitting of a container.

WO 2017/042426 A1 discloses a mechanism for locking a turnbuckle.

The problem identified is that there, in external double lashing configurations, is an unbalanced force distribution between a pair of adjacent container lashing rods which secure or lash a lower corner of an upper container and

DK 2017 70664 A1 an upper corner of a lower container. Typically the upper lashing rod may experience up to 80% of the load between the pair of lashing rods.

The unbalanced force distribution arises because, as indicated above, that there often is a small amount of play in or around the twist locks. Typically the play, or the resulting gap, is in the range of up to 12 mm. This means that the upper container may be attempting to pivot or move slightly about, or with respect to, the lower container resulting in that the pair of lashing rods does not take up equal force.

In conclusion, the disproportionate load distribution between upper and lower lashings in external double lashing configurations causes additional stress and damage to the containers and it is an object of the present invention to solve this problem.

It is an object of the present invention to set forth a stiffness tuned container lashing rod, a lashing system, a method of lashing containers and a method of manufacturing a stiffness tuned lashing rod configured for lessening stress and thereby prevent damage to lower corners, or lower corner castings, of upper containers stowed on top of lower containers.

It is moreover an object of the present invention to at least partially balance the loads imposed on containers as well as lashing gear in external double lashing configurations.

It is finally an object of the present invention to set forth a resilient one-piece lashing rod allowing for easy handling.

Today, ship operators are often applying so-called external double lashing to secure the uppermost tiers of containers stowed on-board container ships.

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External double lashing is a method of lashing containers wherein twin lashing rods and turnbuckles are run nearly parallel from two essentially vertically adjacent container comers; one lower corner of an upper container and the upper corner just below of a lower and underlying container. The lashings are run diagonally down and outwards/transverse to respective lashing or attachment points on the ship or on the lashing bridge.

The appended figure 6 illustrates schematically the principle of external double lashing of containers on board a container ship.

External double lashing is applied to obtain a stable container stack while also to allow for high and heavy stacking. One problem is, however, that the lower corner of the upper of two stacked containers may be damaged as a consequence of uneven load distribution between the lashings of the upper and lower containers.

The present invention relates, according to a first aspect, to a stiffness tuned container lashing rod configured for lashing a container to a container ship or to a lashing bridge arranged on a container ship.

According to a second aspect, the present invention relates to a container lashing system.

According to a third aspect, the present invention relates to a method of lashing containers.

According to a fourth aspect, the present invention relates to a method of manufacturing a stiffness tuned container lashing rod.

According to the present invention, the above objects are met by the provision of a stiffness tuned container lashing rod according to the introductory part of this specification wherein the stiffness tuned container

DK 2017 70664 A1 lashing rod comprises one or more expansion sections disposed in-between a first end section and a second end section of the stiffness tuned container lashing rod. The one or more expansion sections is/are configured to be resiliently expandable, following application of tensile force to the stiffness tuned container lashing rod, by a distance which is greater than any expansion of the first end section and/or the second end section of the stiffness tuned container lashing rod.

A stiffness tuned container lashing rod is, within the context of this specification, an elongate lashing rod having designed or customized elongation characteristics allowing for controlled or engineered elongation following application of certain longitudinal loads, or tension, to the stiffness tuned container lashing rod.

The stiffness tuned lashing rod is configured to be resiliently expandable such that the expansion length under a unit load can be tuned to a selected value larger than the expansion of a standard non-tuned lashing rod with the same or corresponding strength and length; i.e. a similar lashing rod without an expansion section.

When coupled with a turnbuckle between a container and a fixed attachment point, the stiffness tuned lashing rod forms a complete lashing with bespoke elongation characteristics under axial load.

The above objects are further met by the provision of a stiffness tuned container lashing rod, a container lashing system and a method of lashing containers according to the appended claims.

The invention allows for improved and simplified load balancing between parallel lashings as the invention will allow an upper container to move or shift slightly without applying excessive loads, or excessive dynamic loads, stemming from ship movement, weather or any play or gaps between the

DK 2017 70664 A1 lashed containers, to the stiffness tuned container lashing rod. This in effect eases loads imposed to the upper lashing rod and thereby also to the lower corner of the upper container, in external double lashing configurations.

Given that the upper and lower lashing rods may have the same load limit, the upper stiffness tuned lashing rod according to the present invention may be stretched longer before reaching its limit than the lower non-tuned lashing rod.

The present invention moreover will allow for higher container stack loads while preventing damage to the containers and/or the lashing gear.

According to the second aspect, the present invention provides a container lashing system including a pair of lashing rods that provides asymmetry in the amount that they allow upper and lower containers to move with respect to each other when the lashings are under load. The difference in allowed movement of the containers is due to variation in the stiffness of the lashing rods.

The difference in allowed movement of the containers will have the effect that load is transferred from the upper lashing to the lower lashing while giving the overall container stack a slightly larger deflection under load, or under dynamic loads stemming from ship movement etc.

Therefore, in external double lashing configurations with two essentially parallel lashings where the upper lashing has a suitably selected lower stiffness, according to the present invention, than the lower one, the following effects would occur:

- Compared to a system with uniform lashing stiffness the load in the upper lashing will be lower.

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- Compared to a system with uniform lashing stiffness the load in the lower lashing will be higher.

- Compared to a system with uniform lashing stiffness the load in twist locks between containers will increase.

- Compared to a system with uniform lashing stiffness the overall deflection under load of the stack above the lashing will increase.

Given that the limiting factor in many recent container damages is the load exerted from the upper lashing on the lower container corner, the present invention will allow for heavier container stacks and/or reduce the frequency of damage to the containers as well as the lashing gear.

According to one embodiment, the one or more expansion sections is/are resiliently expandable by a distance which, relative to the length of the sections, is greater than any expansion of the first end section and/or the second end section.

According to one embodiment, the predefined combined stiffness of the stiffness tuned lashing rod and standard turnbuckle may be engineered to be in the range of 40% to 100% of the similar standard and nun tuned lashing rod and turnbuckle, this being equivalent to allowing an elongation under axial load of 2.5 to 1 times the elongation of a non-tuned standard lashing rod and turnbuckle combination before the load limit is reached.

According to one embodiment, the one or more expansion sections may form integral parts of the stiffness tuned container lashing rod. By this, simplified manufacturing and handling is provided.

According to one embodiment, the one or more expansion sections may have geometrical cross sections which are different from the geometrical cross section of one or both of the first end section and/or the second end section of the stiffness tuned container lashing rod.

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According to one embodiment, the stiffness tuned container lashing rod may be provided with one or more expansion sections arranged along the length of the stiffness tuned container lashing rod. By this, flexibility in manufacture as well as properties is obtained.

According to one embodiment, the one or more expansion sections may define one or more openings or loops or rings and the one or more openings or loops or rings may change shape or dimension when the first load range is imposed on the stiffness tuned container lashing rod.

According to one embodiment, the one or more expansion sections may be embodied as one or more intermediate rods or equivalent interconnecting the first and the second end sections of the lashing rod via bending flanges or bridges. In this embodiment, elongation of the lashing rod may be provided by the intermediate rods and/or by the bending flanges or bridges which may be configured to bend when tension is applied to the lashing rod. The tuning in this embodiment may be achieved by selecting the properties such as the dimensions or the material of the bending flanges or bridges in accordance with the desired elongation characteristics of the stiffness tuned lashing rod.

According to one embodiment, the one or more expansion sections may be embodied as spring sections.

According to one embodiment, the lashing rod may at least partially be manufactured from spring metal or aluminium or a composite material with a different Young's modulus than steel.

According to one embodiment, the first end section of the lashing rod may be provided with engagement means such as ribs or threads configured for engaging with a turnbuckle. Furthermore, the second end section may be provided with engagement or hook means configured for engaging with a

DK 2017 70664 A1 container or a container casting of a container. By this, a stiffness tuned container lashing rod compatible and interchangeable with standardized lashing equipment is provided, thus facilitating simple and cheap retrofit.

According to the second aspect of the present invention, a container lashing system for lashing a lower container and an upper container is provided. The system includes a stiffness tuned upper container lashing rod and a nontuned lower container lashing rod. The stiffness tuned upper container lashing rod is a stiffness tuned container lashing rod according to the first aspect of the present invention and the lower lashing rod is a non-tuned container lashing rod. Moreover, the first end section of the stiffness tuned upper container lashing rod may be identical to a first end section of the nontuned container lashing rod such that one turnbuckle is compatible with the tuned upper container lashing rod as well as with the non-tuned lower container lashing rod.

According to the third aspect of the present invention, a method of lashing containers is provided. The method includes a step of, when lashing stacked upper containers, selecting or applying a stiffness tuned container lashing rod according to the first aspect of the present invention.

Figure 1 shows a prior art container lashing rod.

Figure 2 shows a stiffness tuned container lashing rod according to an aspect of the present invention.

Figure 3 shows the stiffness tuned container lashing rod of figure 2 in a view normal to the view of figure 2.

Figure 4 shows a stiffness tuned container lashing rod according to an aspect of the present invention.

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Figure 5 shows a stiffness tuned container lashing rod according to an aspect of the present invention.

Figure 6 shows schematically an end view of a stack of containers lashed by means external double lashings.

Figure 7 is a partial view of a part of a stiffness tuned container lashing rod under load.

Figure 8 is graph showing the effect of the stiffness tuned container lashing rod.

Figure 1 shows schematically a non-tuned prior art container lashing rod 100.

The prior art container lashing rod 100 may be embodied as a cylindrical rod having first and second end sections 101, 102 interconnected or unified via a central a rod section 103 having essentially constant cross section and without means configured to bend or deflect following application of longitudinal tension. Such prior art lashing rod 100 will be suitable as the lower and non-tuned lashing rod in the lashing system according to the second aspect of present invention.

Figures 2 and 3 show schematically, and in different views, one embodiment of a stiffness tuned container lashing rod 1 according to the present invention.

The tuned lashing rod 1 is in this embodiment provided with one expansion section 10 disposed in-between a first end section 5 and second a second end section 7 of the lashing rod 1. In some embodiments the tuned lashing rod 1, is suitable for securely fastening an intermodal shipping container to another body. For example the tuned lashing rod 1 fastens the container to a lashing bridge, deck or other structural feature of a ship or other mode of transport.

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The expansion section 10 provides reduced stiffness to the stiffness tuned container lashing rod 1. The stiffness tuned container lashing rod 1 may constitute an elongate lashing rod 1 having designed or customized elongation characteristics allowing for controlled or engineered elongation following application of certain longitudinal loads, or tension, to the stiffness tuned container lashing rod. In some embodiments the expansion section 10 of the tuned lashing rod 1, has been configured to extend a predetermined amount under a force when the lashing rod is mounted on a container ship.

The stiffness of a lashing rod is composed of the tensile stiffness of the material used to fabricate the lashing rod as well as of any devices provided inherent to change shape following application of tensile force.

The tensile stiffness is a material constant for steel and for various local bending deflections in the not shown turnbuckle and attaching devices.

Typically the overall stiffness, or the non-tuned system stiffness, of a standard turnbuckle and lashing rod lashing system is some 65% of the stiffness of a homogenous steel rod.

Tuned stiffness of the container lashing rod can, in accordance with the present invention, be achieved by embodying the expansion section 10 in a number of ways including, but not limited to:

- different materials such as steel, titanium, aluminium, or other metals or alloys, carbon fibre, or other composite materials suitable for expanding under load;

- a different shape or topology for example the shape of expansion section can be a loop, a partial loop, a circular hoop, a serpentine shape, or any other suitable shape that promotes additional flexibility in the lashing rod;

- a different cross section such as circular, square, oval or any other suitable cross sectional shape;

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- multiple components configured to bend or deflect or elongate

- combinations of one or more of the above features.

In figures 2 and 3, the expansion section 10 is embodied as two essentially parallel rods 12, or intermediate rods 12, interconnecting the first and the second end sections 5, 7 of the tuned container lashing rod 1 via bending flanges or bridges 13. Following application of tension, the bending flanges or bridges 13 will bend slightly thereby allowing the stiffness tuned lashing rod 1 to elongate slightly while still applying lashing force to the lashed container 50.

In figures 2 and 3 there are two parallel rods 12. In other embodiments there can be a plurality of parallel and/or non parallel rods 12. For example, there can be three, four, five rods 12. The number of parallel rods 12 can vary the amount of stiffness of the lashing road and the amount that the expansion section 10 is allowed to flex.

Figure 7 shows a part of a stiffness tuned lashing rod 1 under application of tension. As can be seen, the bending flange or bridge 13 bends slightly following application of tension. In some embodiments the size, shape and composition of the bridge 13 can be varied. By modifying the characteristics of the bridge 13, the stiffness of the expansion section 10 can be further modified.

By engineering the dimensions of one or more of the intermediate rods 12 and/or the bending flanges 13, a stiffness tuned lashing rod 1 with varying and bespoke stiffness can be designed and manufactured.

Typically the tuned lashing rod 1 is manufactured and cast from steel. In other embodiments, the tuned lashing rod 1 can be manufactured by other methods. For example if the tuned lashing rod 1 comprises composite materials, the different materials can be adhered or fastened together. Once

DK 2017 70664 A1 manufactured, the stiffness properties may be fixed and not open for operator’s adjustment.

A suitable balance between stiffness of the stiffness tuned container lashing rod 1 and a standard or non-tuned container lashing rod 100 may be selected at the design stage.

The bending flanges 13 or bridges as well as the intermediate rods 12 may, as an example, be made from metal such as spring steel which generally is a low-alloy, medium or high carbon steel.

In embodiments wherein the intermediate rods 12 are made from resilient material, the stiffness tuned lashing rod 1 according to the present invention expands by means of elongation of the intermediate rods 12.

Other metals, alloys or other materials that allows the expansion section 10 to return to its original shape or form following multiple expansions may equally be provided.

In other embodiments, the stiffness tuned container lashing rod 1 including the expansion section 10 may, as an example, be made from suitable metallic material either cast as one unit or manufactured by assembly of separate parts by, for example, welding. Moreover, other arrangements of the expansion section 10, such as circular or array arrangement of more than two expansion sections 10 may equally be applied.

In the embodiment according to figures 2 and 3, the intermediate rods 12 are made from a weldable metal and joined to the flanges or bridges 13 and the first and the second end sections 5, 7 of the stiffness tuned container lashing rod 1 by means of welding.

Other forms of interconnections, such as not shown threaded connections or clamps etc., may equally be applied.

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Other embodiments of the stiffness tuned container lashing rod 1 according to the present invention are shown in figures 4 and 5. As can be seen, the expansion sections 10 are embodied as one or more loops or rings 14 and the loops or rings 14 may be joined with the first and second end sections 5, 7 by means of welds etc.

As can be seen from figure 4, the loop 14 is circular. In other embodiments the shape can be other regular shapes such as oval, square, or triangular. In other embodiments the loop 14 is an irregularly shaped loop. In yet other embodiments the expansion section 10 can be a partial loop, a curve, a crescent shaped or have serpentine path. In some embodiments the expansion section 10 comprises a plurality of loops coupled longitudinally along the axis of the tuned lashing rod 1.

Figure 5 shows two identical loops 11,14 side by side. In some other embodiments the loops 11,14 can be different shapes and sizes.

In other embodiments, the stiffness tuned container lashing rod 1 may be cast or moulded as a single piece of cast steel without welding.

Figure 6 shows schematically a partial end view of a stack of containers 50, 51 lashed by means external double lashings 1, 100. The figure shows upper containers 50 and lower containers 51 resting behind a lashing bridge 20. The lashing bridge 20 is connected to the structure of a vessel such as a container ship.

The lashing bridge 20 accommodates upper anchor points 25 for lashing upper containers 50 and lower anchor points 26, arranged below the upper lashing points 25, for lashing lower containers 51.

The external double lashing is performed by means of non-tuned lashing rods 100 connecting the lower containers 51 with the lower anchor points 26

DK 2017 70664 A1 and with stiffness tuned lashing rods 1 according to the present invention connecting the upper containers 50 with the upper anchor points 25.

Figure 8 shows schematically the calculated effects of various tuned container lashing systems as shown in figure 6. The horizontal axis denotes the total stiffness of the stiffness tuned lashing rod combined with a standard turnbuckle as a fraction of the stiffness of the lower lashing composed of a standard lashing rod with a turnbuckle. 100% denotes that both lashings are equal (no tuning) and 50% would mean that the upper lashing will elongate twice as much for a given load than the lower.

The curve 71 shows the lashing force in the upper lashing with the tuned lashing rod.

The curve 72 shows the lashing force in the lower lashing with a standard lashing rod.

It should be noted, for the calculated example, that the forces balance in the upper and lower lashings when the tuned lashing has a stiffness of about 45% of the lower lashing and that significant reductions in load in the upper lashing is realised already at much more modest stiffness decreases.

The curve 74 shows the twist lock force between the upper and lower container.

A further embodiment is further provided which combines one or more features of from different the previously described embodiments.

This invention may be embodied in several forms without departing from the scope of essential characteristics thereof. The present embodiments are therefore illustrative and not restrictive since the scope of the invention is defined by the appended claims rather than by the description preceding them. All changes that fall within meters and bounds of the claims or

DK 2017 70664 A1 equivalence of such meters and bounds thereof are therefore intended to be embodied by the claims.

Claims (16)

1. Claims

   1. A stiffness tuned container lashing rod (1) configured for lashing at least one container (50), (51) to a container ship (20) characterized in that the stiffness tuned container lashing rod (1) comprises one or more expansion sections (10) disposed in-between a first end section (5) and a second end section (7) of the stiffness tuned container lashing rod (1) and wherein the one or more expansion sections (10) is/are configured to be resiliently expandable, following application of tensile force to the stiffness tuned container lashing rod (1), by a distance which is greater than any expansion of the first end section (5) and/or the second end section (7).
2. 2. A stiffness tuned container lashing rod according to claim 1, wherein the one or more expansion sections (10) is/are resiliently expandable by a distance which, relative to the length of the sections, is greater than any expansion of the first end section (5) and/or the second end section (7).
3. 3. A stiffness tuned container lashing rod according to claim 1 or 2, wherein the one or more expansion sections (10) is/are resiliently expandable by a predetermined distance, either independently or collectively, of approximately 1 - 4 times the expansion of the first end section (5) and/or the second end section (7) following application of tensile force to the stiffness tuned container lashing rod (1).
4. 4. A stiffness tuned container lashing rod according to any one or more of the foregoing claims, wherein the one or more expansion sections (10) form integral parts of the stiffness tuned container lashing rod (1).
5. 5. A stiffness tuned container lashing rod according to any one or more of the foregoing claims, wherein the one or more expansion sections (10) has a geometrical cross section which is different from the geometrical cross

   DK 2017 70664 A1 section of one or both of the first end section (5) and/or the second end section (7) of the stiffness tuned container lashing rod (1).
6. 6. A stiffness tuned container lashing rod according to any one or more of the foregoing claims, wherein the stiffness tuned container lashing rod (1) is provided with one or more expansion sections (10) arranged along the length of the stiffness tuned container lashing rod (1).
7. 7. A stiffness tuned container lashing rod according to any one or more of the foregoing claims, wherein the one or more expansion sections (10) define one or more openings (11) or loops or rings (14) and wherein the one or more openings (11) or loops or rings (14) change shape or dimension when the one or more expansion sections (10) expands.
8. 8. A stiffness tuned container lashing rod according to any one or more of the foregoing claims, wherein the one or more expansion sections (10) is/are embodied as one or two or more essentially parallel rods (12) interconnecting the first and the second end sections (5), (7) via bending flanges (13) or opposed bending flanges (13).
9. 9. A stiffness tuned container lashing rod according to any one or more of the foregoing claims, wherein the one or more expansion sections (10) is/are embodied as spring sections.
10. 10. A stiffness tuned container lashing rod according to any one or more of the foregoing claims, wherein the one or more expansion sections (10) is/are made from a material with different Young's modulus than steel, for example aluminium or a composite material.
11. 11. A stiffness tuned container lashing rod according to any one or more of the foregoing claims, wherein the first end section (5) is provided with engagement means such as ribs (4) or threads configured for engaging with

    DK 2017 70664 A1 a turnbuckle (40) and wherein the second end section (7) is provided with engagement or hook means (6) configured for engaging with a container (50), (51) or a container casting (55) of a container (50), (51).
12. 12. A container lashing system for lashing a lower container (51) and an upper container (50) where the lashing system includes an upper container lashing rod (1) and a lower container lashing rod (100) wherein the upper container lashing rod (1) is a stiffness tuned container lashing rod (1) according to any one or more of the foregoing claims and wherein the lower container lashing rod (100) is a non-tuned container lashing rod (100).
13. 13. A container lashing system according to claim 12, wherein the first end section (5) of the upper container lashing rod (1) is identical to a first end section (101) of the non-tuned container lashing rod (100) such that one turnbuckle is compatible with the stiffness tuned container lashing rod (1) as well as with the non-tuned container lashing rod (100).
14. 14. A method of lashing containers including a step of, when lashing stacked containers (50), (51), selecting a stiffness tuned container lashing rod (1) according to any one or more of the foregoing claims for lashing a container (50) stowed on top of an underlying container (51).
15. 15. A method of manufacturing a stiffness tuned container lashing rod wherein the method includes a step of casting a lashing rod including one or more expansion sections disposed in-between a first end section and a second end section as a one piece casting.
16. 16. A method of manufacturing stiffness tuned container lashing according to claim 15, wherein the stiffness tuned container lashing rod is a stiffness tuned container lashing rod according to any one or more of the claims 1-11.