Something Feral

Digging up the flower-beds.


Saturday, August 16, 2008

Skill Sets: Rope Use

I'll start with a topic that I have an arguable level of expertise in: knots, lashings and splices. The following knots are the minimal level of proficiency; there are other knots that are useful, but these knots span the range of useful application for most people.

Remember: Any knot or splice will weaken the rope, so be mindful of the working-load allowances.

- Anchor Bend: While not a "bend" in the contemporary sense, an excellent hitch for general use; it has an exceptionally high strength-rating.

- Bowline: The original non-slip loop, used often as a rescue knot. It's rumored that the pharaoh Khufu that commissioned the Great Pyramid at Giza was buried with a "solar barge", and some of the lines were tied-off with bowlines.

- Constrictor Knot: An infinitely better substitute for the Clove Hitch, in my opinion. The Constrictor self-tightens on twisted rope, and grips to slick surfaces more firmly as a result.

- Figure-Eight with follow-through, plus Double Overhand: The standard way to tie into a climbing-harness today. The figure-eight won't overtighten under strain, which is a big bonus when it comes time to remove the rope from the harness. If you have plenty of rope, use this instead of a bowline.

- Prussick Hitch: I love this knot, as it makes the application of force parallel to the object very easy. I used this to replace fence-posts a few summers ago.

- Sheet Bend: Notice the similarity to the bowline; the sheet bend inherits all of the non-slip properties. Unlike the square-knot/reef-knot, which has been known to capsize under strain, the sheet-bend is a very stable and robust bend. Personally, I will use a double sheet-bend for added security if needed.

- Tauntline Hitch: An adjustable-loop hitch that maintains its position under strain. Extremely handy for almost everything.

- Timber Hitch: Useful for hauling items around, particularly timber (imagine that). Be sure to keep the rope from rubbing on the ground when using this knot.

- Truckers' Hitch: I'm providing the link here for basic form; the variation I use on a regular basis for its non-jamming nature is at Wikipedia:



As one might infer from the title of the knot, the Truckers' Hitch is generally used to tie-down a load on a truck, car or other conventional vehicle. It may be re-adjusted after having tied-off the running end by undoing the knot (typically a slippery-hitch or two half-hitches), applying tension, then retying the stopper-knot.

Bonus:

While knots are wonderful things, lashings and splices have an equal or superior amount of utility. Splices, being constructs from braiding the rope (or cable) back into itself, have a greater percentage of structural integrity of the original rope than almost any other knot. The eye-splice and short-splice are particularly noteworthy.

Lashings bind two or more objects (usually spars) together. The square-lashing and the diamond-lashing are the most frequently used, but the tripod-lashing gets a special mention for pure utility. A few pointers:

- Use a Constrictor Knot instead of a Clove Hitch. Your lashings will be tighter, and thus more secure.

- If attempting a tripod-lashing, keep the lashing somewhat loose (about an inch between spars and ropes). The lashing tightens when the tripod is erected, and an overly-tight lashing will snap the spars, rope, or simply fail to open enough to stand.

- Natural-fiber twisted rope seems to grip spars more effectively, from my experience. Manila-hemp rope seems to be a inexpensive and frequent choice.

2 comments:

Chris said...

Just letting you know there's a tool that works just like a truckers hitch but without all the knot tying, its called a TiteTie. It works with any size and type of rope and doesn't need tying off. It is made from hardened steel, is rated for 1900lbs and has so many advantages over the truckers hitch, check it out at http://www.titetie.com.au

Something Feral said...

That's a neat little device there, and if I see them for sale domestically, I'll probably grab a few. I do love gadgets.

However, like car keys, eventually they get lost... Hence my argument for at least having the knowledge to fix the situation with the truckers' hitch.