Cargo securing for maritime transport


The need for common guidelines for safety at sea had already been recognized at the time the UN was founded. The IMO convention was adopted in 1948 and entered into force in 1958. The IMO’s first task was to adopt a new version of the International Convention for the Safety of Life at Sea (SOLAS), which was achieved by 1960. The many accidents involving oil tankers raised awareness for the need for greater environmental safety. This resulted in the International Convention for the Prevention of Pollution from Ships (MARPOL) in 1973/78.

Over the years, further conventions and codes have been established covering a great variety of areas all focusing on safety and the environment. One example of these additional instruments is the International Maritime Dangerous Goods Code (IMDG Code). It became mandatory for all countries in 2012.

The International Maritime Organization – is the United Nations specialized agency with responsibility for the safety and security of shipping and the prevention of marine and atmospheric pollution by ships.

IMO's work supports the UN sustainable development goals.


The currently applicable version, the SOLAS 1974 International Maritime Treaty, comprises 14 chapters that each address various areas of safety at sea. The chapter we are concerned with here is Chapter VI, Carriage of Cargoes. (Dangerous goods are dealt with in Chapter VII.)

Chapter VI
Chapter VI is broken down into three parts: Part A, Part B, and Part C. The various parts cover a number of regulations, some of which concern the securing of cargoes.

Timber Deck Cargo Code (TDC Code)
Chapter VI Regulation 1.2 refers to the TDC Code, which in turn is regulated by Resolution A.1048(27). It includes requirements for lashing arrangements to be used to secure timber deck cargoes. Among others, the code specifies requirements for elongation, tension force, lowest breaking strength of lashing devices, and acceptable deformation. The current version as per this writing is dated from 2011 (2012 edition).

International Convention for the Safety of Life at Sea

The SOLAS Convention in its successive forms is generally regarded as the most important of all international treaties concerning the safety of merchant ships.

CSS Code

The CSS Code can be found in Chapter VI, Regulation 5. Among other things, it lists the calculation methods for lashings onboard ships (Annex 13). The same annex also contains a table that describes the relationship between Maximum Securing Load (MSL) and breaking strength of various lashing types (Annex 13, Chapter 4).

Chapter 4 contains a reference to IMO Resolution MSC 102/J/8, Guidelines for securing arrangements for the transport of road vehicles on ro-ro ships. It previously contained a requirement for a minimum breaking strength of 200 kN (MSL 100 kN) for the lashing of road vehicles with a GVM of more than 15 tons. This requirement has now been dropped (the document’s former name was Resolution A.581).

Code of Safe Practice for Cargo Stowage and Securing (CSS Code)

The accelerations acting on a ship in a seaway result from a combination of longitudinal, vertical and predominantly transverse motions.  The forces created by these accelerations give rise to the majority of securing problems.  The hazards arising from these forces should be dealt with by taking measures both to ensure proper stowage and securing of cargoes on board and to reduce the amplitude and frequency of ship motions.

CTU Code

MSC.1/Circ.1497 describes the Code of Practice for Packing of Cargo Transport Units (CTU Code). The circular MSC.1/Circ.1498 contains informative material related to the CTU Code.

The CTU Code was produced by the three UN agencies IMO, ILO, and UNECE, and it describes how cargo items can be secured in a cargo transport unit, i.e. inside a container, a trailer, or a flatrack. One of the code’s aims is to facilitate the work involved in securing cargo goods right from the start of the transport, e.g. at an industrial production facility. However, there may be some differences with national regulations for land transport, which can lead to uncertainties. The code includes a number of tables and quick reference guides as well as sound tips about how to safely carry out the securing of cargoes in the three different sea areas defined (A-C).

The code is connected to the SOLAS in that the CSS Code refers to the CTU Code for the securing of cargoes in cargo transport units. The code is also connected to SOLAS Chapter VII, since even the IMDG Code refers to the CTU Code. Some countries have included the code in their regulations, e.g. in Sweden where it can be found in the Swedish Transport Agency’s regulation TSFS 2010:174. Work on revising the currently applicable version has started and is expected to last until 2024.

Code of Practice for Packing of Cargo Transport Units (CTU Code)

The 2014 IMO/ILO/UNECE Code of Practice for Packing of Cargo Transport Units (CTU Code), jointly developed by the International Maritime Organization (IMO), the International Labour Organization (ILO) and the United Nations Economic Commission for Europe (UNECE), addresses these concerns through a non-mandatory global code of practice for the handling and packing of cargo transport units for transportation by sea and land.

Cargo Securing Manual

The Guideline for the preparation of the Cargo Securing Manual (MSC.1/Circ.1353/Rev.2) describes how cargo securing manuals intended for ships should be compiled. The document, which is referred to in the SOLAS, is a compilation of the tasks to be included in each ship’s particular cargo securing manual.

A specification concerning applicable documentation (certificates) for portable cargo securing devices can be found in section 2.2. Examples of the details included in certificates can be found further down on this page.

Cargo Securing Manual, MSC.1/Circ.1353/Rev.2

Section 2.2 specifies that a document (certificate) regarding portable cargo securing devices should include the following information:

  • Name of manufacturer
  • Type designation with a description of the actual item as well as a simple sketch for ease of identification
  • Specification of material(s), including minimum safe operational temperature
  • Identification marking
  • Strength test result or ultimate tensile strength test result
  • Result of non-destructive testing
  • Maximum Securing Load (MSL)

Excerpt from the TDC Code:

All lashings and components used for securing should:

  • Possess a breaking strength of not less than 133 kN
  • After initial stressing, show an elongation of not more than 5% at 80% of their breaking strength
  • Show no permanent deformation after having been subjected to a proof load of not less than 40% of their original breaking strength.
  • Should be provided with a tightening device or system so placed that it can safely and efficiently operate when required. The load to be produced by the tightening device or system should not be less than:
  • 27 kN in the horizontal part; and
  • 16 kN in the vertical part
  • Should be left with no less than half the tightening capacity available for future use
  • Should permit the length of the lashing to be adjusted

Further requirements can be found in the code.

Excerpt from the CSS Code:

  • Manufacturers of securing equipment should at least supply information on the nominal breaking strength of the equipment in kN
  • Maximum securing load (MSL) is a term used to define the load capacity for a device used to secure cargo to a ship. Safe working load (SWL) may be substituted for MSL for securing purposes, provided this is equal to or exceeds the strength defined by MSL.
  • MSL is the preferred term
  •  The MSLs for different securing devices are given in the table below:

The MSLs for different securing devices are given in the table below:

Material MSL
Shackles, rings, deck eyes, turnbuckles of mild steel 50% of breaking strength
Fiber rope 33% of breaking strength
Web lashing 50% of breaking strength
Wire rope (single use) 80% of breaking strength
Wire rope (re-usable) 30% of breaking strength
Steel band (single use) 70% of breaking strength
Chains 50% of breaking strength

When components of different types are connected in series, the lowest value should apply to the entire securing device.

There is no requirement regarding tension force or any definition thereof.

Point 4.3 in Annex 13 specifies that cargo securing devices marked with a permissible working load, as prescribed by another appropriate authority, can be used in accordance with the latter’s marking and may be considered as equivalent to the MSL. One example of this would be a cargo securing device consisting of bands for land transport in accordance with European standard EN 12195-2 marked with LC (Lashing Capacity). One advantage of these lashings is that a tension force (STF) is specified that can be used in connection with the quick reference guides in the CTU Code.

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