Diagonal lashing is used to bind poles together that cross each other but do not touch when their ends are lashed in place in a structure.
The diagonal lashing gets its name from the fact that the wrapping turns cross the poles diagonally. The diagonal lashing can be used to bind poles that cross each other from 90° to 45°. If the angle between the poles is less than 45° a shear lashing should be used. The diagonal lashing makes use of the timber hitch to pull poles together that are not touching each other. The timber hitch allows the poles to be drawn together without changing the relative positions of the poles. [NOTE] If a square lashing were used to bind poles that do not touch, the beginning clove hitch would pull the cross pole toward the clove hitch causing unnecessary bowing of the cross pole and could also produce a force that would act along the length of the pole to which the clove hitch is tied. These additional forces, if strong enough, can place unnecessary strain on other lashing within the structure causing the structure to twist and fail.
If very smooth rope is used, the lashing can be made more secure by adding a third or fourth half hitch to the clove hitch.
A shear lashing around 3 poles.
To bind three poles together, for the construction of a tripod. To bind three poles together that contact at the same point in a structure.
The tripod lashing is a shear lashing that binds three poles together at the same point. The tripod lashing gets it name from the fact that its most common use is the construction of a tripod. The tripod lashing can be used just about anywhere in a structure that three poles cross each other at the same point and the same time in the sequence of construction. Tripod lashing takes two main forms; with racked wrapping turns (the rope is woven between the poles) and with plain wrapping turns (the rope is wrapped around the poles without weaving the rope between the poles). When the lashing is made with racking turns the rope contacts each pole around its entire circumference ; this contact makes the tripod lashing with racking turns the most secure form of tripod lashing: therefore tripod lashing with racking turns should be used when safety is important. However, for light structures where there would be no danger if the lashing slipped, the faster to tie tripod lashing with plain wrapping turns may be used
For most tripod lashings, lay the pole side by side with the butt ends aligned. The alignment of the butts of the pole insures that the tripod legs are the desired length
The practice of laying the center pole in the opposite direction to the outside poles creates several problems. When the poles are laid in opposite directions the wrappings must be put on loosely so that when the center pole is rotated to its proper position the lashing is tightened around the poles. If the wrappings are put on too tight, the rope is stretched causing damage to the rope fibers, therefore weakening the lashing. On the other hand, if the rope is wrapped two loosely, the lashing will not tighten enough when the center pole is rotated and the lashing will be able to slip along the length of the pole. Either way, the rope to loose or the rope too tight, a dangerous situation is created.
Set up the tripod by crossing the outside poles so that the cross point of the poles is under the center pole. Crossing the outside poles under the center pole causes part of the load that is placed on the tripod to be taken up by the wood to wood contact of the poles.
A sheer lashing is often used to bind adjacent poles together. It is also a good way to reinforce a broken or weak pole. The frapping turns used to tighten the lashing may be omitted and replaced with wedges inserted between the poles.
A loose Sheer Lashing made around the ends of two poles will allow the poles to be opened out and used as an A-frame. It can also be used to form a tripod just like the Figure-of-eight lashing.
An A-frame lashing or Sheer Legs is made in the same way as a Sheer Lashing with the lashing and frapping turns made slightly loose so that the poles can be opened out. It is often used to raise a boat mast or to form the legs of a rope bridge. You must take care to ensure that the legs of the frame do not slip.
Take a tripod by using a Figure-of-eight lashing on three poles. Set up the tripod by crossing the outside poles so that the cross point of the poles is under the center pole. This makes sure that part of the load is taken by the wood in contact.
If a symmetrical arrangement of the poles is needed within a structure the tripod can be set up by rotating the poles around the lashing. This means that the load is supported only by the ropes and the joint becomes flexible and so the tripod may become unstable.
Ladder lashing allows for a quick and secure method for constructing a ladder or for constructing a decking with evenly space decking pieces.
This form of lashing has several advantages over the traditional floor lashing. Less material is required because unlike floor lashing a space can be left between each piece of the decking. Also, each rung is securely lashed in place by several loops of rope in much the same way as a square lashing; with the traditional floor lashing only a single loop of the rope holds each end of the decking in place, therefore if one piece loosens, the entire deck loosens.
The ladder lashing has two forms; left and right, each is a mirror image of the other.