Will this really hold – can lashing hooks hooked into one another be used safely?
We have tested the safety of makeshift ‘hook-in-hook’ lashing hook connections in accordance with the relevant standard. These are the results:
Our findings on the testing of hook-to-hook connections
- Most improvised hook connections are not safe!
- Many connections fail even under the prescribed test loads.
- Only the symmetrical connection of identical hooks (Fig. 3) passed all the tests.
- For safe applications, only suitable connection solutions designed for this purpose should be used.
Table of contents.
Lashing hook connections: Our tests at the Dolezych testing laboratory
The following were tested profile hooks (also known as j-hooks), such as those typically used to connect lashing straps to lashing points or external frame perforated profiles. Characteristics of the tested Dolezych quality hooks to ensure comparable results and rule out additional influencing factors: new and unused, welded, identical hook types.
The following connection methods between the profile hooks were tested (Figs. 1–4).
The test set-ups were carried out on certified testing machines of accuracy class 1.
The result: most hook-to-hook connections are not secure
The test results were clear:
- Even the load test prescribed in DIN EN 12195-2 failed to pass the load test. This test requires a lashing hook to withstand a load of more than 25 per cent of its LC (Lashing Capacity) without deformation or malfunction.
- Almost all hook connections also failed the subsequent standardised tensile test. In this test, the hooks must be able to withstand a load of twice their LC without breaking.
The investigations clearly show: Improvised hook connections can fail in practical use and must therefore never be used! Most of the lashing hook connection methods examined are not safe.
The only exception: Only the variant in which the hooks are interlocked symmetrically within the hook head (Fig. 3) achieved the required strength in our tests. Provided the lashing hooks are of identical types and meet all standard requirements, this connection is entirely feasible in practical use.
How to avoid risky improvisations with hook connections
The safest solution is to select lashing equipment appropriate to the task.
This includes, for example:
- Strapping lashing straps of sufficient length
- two-part systems with lashing hooks specifically designed for this purpose
- Connection solutions designed specifically for this application
- Patented Dolezych DoConnect hook for securely connecting or extending lashing straps
- A flexible alternative: the adjustable textile chain DoNova® PowerLash thanks to its versatile applications
Customised lashing straps with DoConnect hooks.
To customise your lashing straps with our DoConnect hooks, you can use our lashing strap configurator.
We’ll answer your questions!
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