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April 26, 2007

Square lashing checklist


There is more to tying a safe, secure square lashing then just knowing the "clove hitch, wrap around three times, frap around three times, clove hitch" formula. These guidelines, based on scoring sheets for pioneering competitions, help ensure that lashings are tied 'correctly'. These guidelines make the lashing safer, they're not just for the sake of competition. Here is our square lashing checklist that is used by the Patrol Leader to check all lashings tied:

1. Starting in the right place ?
Having all lashings start in the same place means that it is easier to check lashings, and also easier to untie lashings at the end of the weekend. For a raft, it is typically towards the back of the raft. For a tower structure, the clove hitch normally starts on the vertical member, at the bottom so as to support the horizontal member


2. Clove hitch twisted into rope ?

The 'tail' of the starting clove hitch is twisted around the running end of the rope- this tucks the end of the rope away, which makes the lashing look tidier, but also makes the lashing safer because this hitch is locked more securely

3. Three turns around, all neat and no crossings ?
Three is a good number of turns around a lashing to ensure a solid joint. A specific number is chosen so that all lashing look the same size and can be easily checked. Neat lashings are also strong lashing: crossed turns result in parts of the ropes that are 'pinched' and can be damaged.

4. Three frapping turns, no crossings?
Again, 3 frapping turns is a good number for security.

5. Tight?
A general guideline for tightness of lashings is that one finger pushing on the frapping turns should be unable to move the rope. Again, this is a safety issue.

6. Clove hitch ending in the right place ?
All lashing end with their final clove hitches in the same place. The ending clove hitch should be on the other pole from the starting hitch. On a raft, this is done in terms of inside and outside of the structure, rather than left or right: on the outside poles of a raft, it is safer to have the hitch towards the inside where it will not catch and possibly untie

7. Half-hitches around pole to finish ?
Any excess length of rope follows on immediately after the final clove hitch with a series of half-hitches. Of course, ropes should be very close to the right length for a particular job, put it is better to use a slightly longer rope than a slightly shorter one :)

8. End neatly tucked away ?
This is a safety issue that is again disguised to look like a neatness issue. A free end sticking out of a lashing can potentially get caught and cause the lashing to come untied.

Now as for how this is actually checked: You can visually check whether any of the ends of the rope are sticking out. The rest of the check is done by hand- running your fingers along the lashing, underneath the pole and around the frapping turns. If the lashing is tied correctly, your hands should run smoothly without catching on anything. Each lashing takes a few seconds to check.
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