Construction lashings and their use when building structures.
Construction Lashings and Structures
Lashings are used to firmly hold together two or more spars (poles, masts, scaffolding, legs, trestles, etc.) There are numerous survival construction projects that require lashings for construction.
Here is an example of lashings used to hold two posts together (details on how to create lashings below).
Three basic types of Lashings
There are three basic types of lashings. The choice of which type of lashing to use are dependent upon the job the spars need to perform.
- Square Lashing: used where the spars under load have a tendency to slide over each other at the corners.
- Diagonal Lashing: used where the spars may spring away from each other when under a load.
- Sheer Lasing: used where spars have to share a load or for joining two spars end-to-end.
Square Lashing (used when spars tend to slide over each other)
Step 1: Place the spars in position.
Step 2: Secure one end of the lashing to the vertical spar using a Clove Hitch knot. Tie the hitch below the horizontal spar.
Step 3: Wrap turns under and behind the horizontal spar, over the top part of the vertical spar (above the horizontal spar), and behind the other side of the horizontal spar. Make three or four turns and work tight each turn made.
Step 4: Wrap three or four more turns but this time wrap them over and above the horizontal spar, behind and over the top of the vertical spar, and over and down the other size of the horizontal spar. Tighten each turn.
Step 5: Finish with a Clove Hitch knot on the horizontal spar.
Diagonal Lashing (use when spars tend to spring away from each other)
Step 1: Tie a tight Timber Hitch diagonally (vertically) over the crossing.
Step 2: Continue with three or four tight turns in the same vertical direction as the Timber Hitch. Then wrap three or four tight turns horizontally over the crossing.
Step 3: Finish with a Clove Hitch on one of the spars.
Shear Lashing (use when spars have to share a load)
Step 1: Start with the legs parallel to each other.
Step 2: Tie a Clove Hitch around one of the spars.
Step 3: Wrap about 10 turns around the spars pulling tightly after each turn is made.
Step 4: Splay out the legs to the required angle. The tension on the lashings should remain tight.
Step 5: Then wrap 3 or 4 turns vertically where the spars cross.
Step 6: Finish with a Clove Hitch on one of the spars.
When lashing two poles end to end, complete steps 1, 2, and 3 but do not splay the legs apart and use about 20 turns instead of 10. Finish with a Clove Hitch around both poles. You can drive a piece of wood in between the poles to tighten the lashing.
Other types of lashings
Below are a collection of various types of lashings.
Japanese Square Lashing
Figure of 8 Lashing
Filipino Diagonal Lashing
This lashing required only one knot at the end. Pull all lashing tight to complete.
Step 1: Start with a bight and put this around both spars as shown.
Step 2: Take the two ends back and pull tight.
Step 3: Lash with both ropes as shown.
Step 4: Turn and lash in the opposite direction.
Step 5: Divide the ropes between the spars, adding frapping turns (tight binding) as needed.
Step 6: Pull tight and finish with a Reed knot.
Gin Tripod Lashing
A quick, strong lashing for lightweight tripods.
Step 1: Make a loop over one of the poles with the ends leading between
the other two.
Step 2: Lead the long end of the rope above the loop and wrap it around all three poles about five or six times. Put the loop over the wraps and over top of same pole.
Step 3: Pull the loop tight with the short end of the rope. Lead the short end over the wraps in the between two poles opposite the loop.
Step 4: Tie the ends of the rope together with a square knot between the ends of the poles.
West Country Shear Lashing
This lashing is a series of overhand knots made on alternating sides and finished with a Square Knot. Two lashings make a strong shear joint between two poles.
Below are various survival construction projects that use some of the lashings discussed above.
Here are various ways to anchor construction objects.
The trestle demonstrates pioneering construction techniques. Begin by lashing the ledgers to the legs and add the braces. The center diagonal lashing should be tied last. Bracing diagonally give the structure adding great strength and rigidity. This technique is called triangulation. Note that one end of the brace is opposite the other four ends to add locking tension to the brace.