Lashing (ropework)
From Wikipedia, the free encyclopedia
A lashing is an arrangement of rope used to secure two or more items together in a somewhat rigid manner. Lashings are most commonly applied to timber poles, and are commonly associated with the scouting movement and with sailors.
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[edit] Technique
The structure of a lash is nearly the same with each type of lash you do: To start off, you hold the poles in the position that you would like to end up with. You then start do a timber hitch around one of the poles to secure the rope onto the pole, in the case of the stockgrower's lash an adjustable grip hitch or tautline hitch is used as a timber hitch can slip when the lash is opened. Start to wrap the rope around the poles (the way you wrap will change when you do different lashings. Once the rope is wrapped around the poles enough times to be considered very tightly wrapped, you end with two timber hitches and one or two clove hitches.
[edit] Types
[edit] Square lashing
| Square lashing | |
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| Category | lashing |
|---|---|
| ABoK | #2114 |
Square lashing is a type of lashing knot used to bind poles together. Large structures can be built with a combination of square and diagonal lashing, with square lashing generally used on load bearing members and diagonal lashing usually applied to cross bracing. If any gap exists between the poles then diagonal lashing should be used.
Square lashing steps (see image at right);
- Begin with a clove hitch on the vertical pole beneath the horizontal pole and tuck the loose end under the wrapping.
- Wrap in a square fashion about three times around the poles.
- Frap two or three times, pulling often to work the joint as tight as possible.
- Tie two half hitches around the horizontal pole
- Cinch the half hitches into a clove hitch, an additional clove hitch may be added if desired.
When the turns are taken around the vertical pole they should be inside the previous turns. The ones around the cross pole should be on the outside of the previous turns. This makes sure that the turns remain parallel and hence the maximum contact between the rope and wood is maintained.
Strength is improved if care is taken to lay the rope wraps and fraps in parallel with a minimum of crossing.
An alternative method is known as the Japanese square lashing. The Japanese square lashing is similar to the standard square lashing in appearance, but in fact is much faster and easier to use. One drawback to consider is that it is difficult to estimate how much rope is needed, which can lead to needlessly long working ends.
- Begin by placing the middle of the rope under the bottom pole
- Lay both ends over the top pole, and cross under the bottom pole. Do this about three times. Take care to keep the wrappings as tight as possible.
- After the last wrap, cross the ropes again over the bottom pole and frap around the wrappings. Do this enough times (at least 3) to finish with a square knot.
A properly executed lashing is very strong and will last as long as the twine or rope maintains its integrity. A lashing stick can be used to safely tighten the joint.
[edit] Diagonal lashing
| Diagonal lashing | |
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| Category | lashing |
|---|---|
| Typical use | used to bind spars or poles together that cross each other at a 45° to 90° angle |
| ABoK | #2115 |
Diagonal lashing is a type of lashing used to bind spars or poles together, to prevent racking. It is usually applied to cross-bracing where the poles do not initially touch, but may by used on any poles that cross each other at a 45° to 90° angle. Large, semipermanent structures may be built with a combination of square lashing, which is stronger, and diagonal lashing.
Baling twine has sufficient strength for some lashing applications but rope should be used for joining larger poles and where supporting people sized weights.
Diagonal lashing steps (see image at right);
- Begin with a timber hitch around the juncture of the two poles.
- Make three turns in each direction - tightening steadily as you go.
- Make two frapping turns, tightening the joint as much a possible.
- To end, make two half hitches
- Cinch the half hitches into a clove hitch
A lashing stick can be used to safely tighten the joint. Strength will be improved if the first turn is 90° to the timber hitch and if care is taken to lay the rope turns parallel with no crossings.
[edit] Shear lashing
| Shear lashing | |
| Names | Shear lashing, Sheer lashing |
|---|---|
| Category | lashing |
| Efficiency | 100% |
| Related | round lashing |
| Releasing | begin by undoing a clove hitch. Next unfrap [1] the lashing. Next unwrap the rope. Finally, undo the other clove hitch. |
| Typical use | Tying spars or poles together when they must subsequently be swung apart slightly in a scissors motion (shear legs). Shear lashings may also be used in place of round lashings to join spars of unequal thickness in a straight line. |
Shear lashing uses two or three spars or poles, 15 - 20 feet (6.1 m) of rope.
Tying: To tie a shear lashing, begin with a clove hitch around one spar. Then wrap the free end of the rope around both spars about seven or eight times. Make about three fraps around the lashing, and end up with a clove hitch on the second spar.
[edit] Round lashing
| Round lashing | |
| Category | lashing |
|---|---|
| Efficiency | 100% |
| Related | sheer lashing |
| Releasing | begin by undoing a clove hitch. Next unwrap the rope. Finally, undo the other clove hitch. |
| Typical use | Tying two spars at a straight angle where the spars are clean and of equal diameter; if not you should use a sheer lashing or when security of the lashing is vital. |
| Caveat | A lashing stick should be used in all lashing projects where personal safety is a concern. |
The round lashing is a type of lashing also known as vertical lashing.
Materials: Two spars, 15 - 20 feet (6.1 m) of rope.
Comments: Vital to the efficiency of this lashing is the tightness of the lashing itself. Use of a lashing stick is advised.
Tying: To tie a round Lashing begin with a clove hitch around both poles, about six inches from the end of one pole. Then, wrap the free end of the rope around both poles parallel, and below, the clove hitch about seven or eight times. End this portion with a clove hitch. Then repeat the process about six inches from the other end of the spar.
[edit] Tripod lashing
| Tripod lashing | |
| Category | lashing |
|---|---|
| Typical use | Tying three spars together which can be arranged to form a tripod. |
Tying: Place an item such as a log on the ground to support the spars. Place one spar with the bottom end facing in one direction on top of the item. Then, place the next spar on top of the item, but with the bottom end facing in the opposite direction. Finally, place the last spar next to the middle spar. The result should look something like:
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(however, a part of the middle spar should be directly parallel to, and between, the outer two)
Then, tie a clove hitch or timber hitch on one spar on either side. Bring the rope either on top or below of the middle spar; then bring the rope either below or above the last spar (if the rope went on top of the middle spar, it goes below the last spar, and if vice-versa, then the opposite is done). Bring the rope back around in the same alternating manner. After three or four turns, start to frap by wrapping the rope around one section of rope between the first and middle spar three or four times. Bring the rope to the other section and repeat. Then, tie a clove hitch on the last spar. To erect the tripod, turn the spars upright. Then move all spars as far away from each other as possible. Bring them closer to adjust the height and stability of the tripod. To improve stability, one may wish to lash spars to each tripod leg in order to support them better.
[edit] Stockgrower's lash
| Stockgrower's Lash | |
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| Category | lashing |
|---|---|
| Origin | Used by Canadian stockgrowers to close barbed wire gates. |
| Related | Versatackle knot, trucker's hitch(ABoK #2124) both use rope as pulleys. |
| Releasing | Slipknot |
| Typical use | gates or other areas where parrelle timbers are lashed, and ease of releasing is important |
| ABoK | Not in ABoK |
The stockgrower's lash is used to pull and hold closed barbed wire gates. It allows tight gates to be closed without a stretcher by using the tractor post and latch post of a gate as pulleys. This is an important knot to understand even by anyone who comes across such a gate and should be understood before going hiking, hunting, or any other outdoor activities as gates when opened should be closed properly out of respect for landowners.
Uses: The stockgrower's lash is used to pull and hold closed barbed wire gates. It allows tight barbed wire to be closed without a stretcher by using the tractor post and latch post of a gate as pulleys. It can also be used to lash any wooden or steel gate to a post so long as there is space between them and the lashing is wedged to a post.
Tying: Tie an adjustable grip hitch, tautline hitch, or Tarbuck knot to a post or other fixed object. When closing a gate wrap the rope around the upturned post on the gate itself, then the latch post and the repeat three times then wrap around the tractor post so that you are pulling the tractor post towards the latch post, once snug, pull the loose end under the wraps and tight against the post.
Variations: If one has a lariat the loop can be tied around the latch post, lashing is tied the same.
The stockgrowers' lash can be used to pull two posts together so they can be secured by other means such as a wire hoop.
[edit] Buildings
[edit] Lookout platform
This is an extremely difficult structure to make and could be extremely hazardous if done wrong. To make this structure you will need four long and large poles (these should all be nearly equal in length), and 4-16 medium-sized poles. The number of medium poles depends on how high you make the platform. Finally, you will need a large amount of small poles or a flat wooden board for the deck.
To start off, take two of the long poles and place them on the ground parallel to each other. Now take two of the medium-sized poles and lash them together with a square lashing. Lay this 'X' on top of the two parallel poles, and do a diagonal lashing on each of the four corners of the X. You can use another X if the long poles are long enough. Repeat all of what was just written. Now, you will have to make 2 or 4 more X's, depending on whether you used 1 or 2 X's initially, respectively. Stand up both of the sides you just made, so that they are parallel to each other. Take the X's you just made and diagonally lash them to connect the sides together. Now you just need to climb to the top of the tower and use round lashings with the rest of the small poles to make a floor for the top.
