Taut-line hitch
From Wikipedia, the free encyclopedia
| Taut-line hitch | |
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| Names | Taut-line hitch, Rolling hitch, Magnus hitch, Adjustable hitch, Rigger's Hitch, Midshipman's Hitch, Tent-line hitch |
| Category | hitch |
| Related | Rolling hitch, Magnus hitch, Two half-hitches, Trucker's hitch, Adjustable grip hitch |
| ABoK | #62, #1027, #1230, #1729, #1730, #1799, #1800, #1855, #1856, #1857, #1993 |
The Taut-line hitch is an adjustable loop knot for use on lines under tension. It is useful when the length of a line will need to be periodically adjusted in order to maintain tension. It is made by tying a Rolling hitch or Magnus hitch around the standing part after passing around an anchor object. Tension is maintained by sliding the hitch to adjust size of the loop, thus changing the effective length of the standing part without retying the knot.
It is typically used for securing tent lines, by arborists when climbing trees,[1] for creating adjustable moorings in tidal areas,[2] and to secure loads on vehicles. A versatile knot, the Taut-line hitch was even used by astronauts during the second mission to repair the Hubble Space Telescope.[3]
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[edit] Naming
The adjustable loop forms of the Rolling Hitch and Magnus hitch, in addition to being called either of those two names, have also come to be known variously as the Taut-line hitch[2], Tent-line hitch,[2] Rigger's Hitch,[2] Adjustable hitch,[4] or Midshipman's Hitch.[4] These knots are generally shown as being based on one of three underlying hitches: two variants of the Rolling hitch (ABOK #1734 and #1735) and the Magnus hitch (#1736). These three closely-related hitches have a long and muddled naming history that leads to ambiguity in the naming of their adjustable loop forms as well. The Ashley Book of Knots discusses the three loop forms as the Midshipman's hitch (#1799) and two variants of the Adjustable hitch (#1800).[4] See the image to the right for an illustration of these related knots.
The use of the Ashley reference numbers for these inconsistently named hitches can eliminate ambiguity when required.
[edit] Tying
[edit] #1799
Ashley uses the name Midshipman's hitch for this variation. Based on Rolling hitch #1735, this version is considered the most secure but may be more difficult to adjust after being heavily loaded.
- Pass the working end around the anchor object. Bring it back along side of the standing part and make a half-hitch around the standing part.
- Continue by passing the working end over the working part, around the standing part again and back through the loop formed in the first step. Make sure this second wrap tucks in between the first wrap and the working part of the line on the inside of the loop. This detail gives this version its additional security.
- Complete with a half-hitch outside the loop, made in the same direction as the first two wraps, as for a clove hitch.
- Dress by snugging the hitch firmly around the standing part. Load slowly and adjust as necessary.
[edit] #1800
Based on Rolling hitch #1734, this version is the one most often seen named "Taut-line hitch", commonly in non-nautical sources. It is the method taught by the Boy Scouts of America.[5]
- Pass the working end around the anchor object. Bring it back along side of the standing part and make a half-hitch around the standing part.
- Continue with another wrap inside the loop, effectively making a round turn around the standing part.
- Complete with a half-hitch outside the loop, made in the same direction as the first two wraps, as for a clove hitch.
- Dress by snugging the hitch firmly around the standing part. Load slowly and adjust as necessary.
[edit] #1800 with concluding hitch reversed
Based on Magnus hitch #1736, this is exactly as above but with the final hitch in the opposite direction. It can be more tricky to snug-up, since both lines emerge from the same side of the hitch, but it has less tendency to twist under load.
- Pass the working end around the anchor object. Bring it back along side of the standing part and make a half-hitch around the standing part.
- Continue with another wrap inside the loop, effectively making a round turn around the standing part.
- Complete with a half-hitch outside the loop made in the opposite direction than the first two wraps, as for a cow hitch.
- Dress by snugging the hitch firmly around the standing part. Load slowly and adjust as necessary.
[edit] Adjusting
Once snug and set, the hitch can be adjusted as needed. To tighten the line with respect to a load attached to the standing part, grasp the standing part with one hand inside of the loop and pull towards the anchor object. Grasp the hitch with the other hand and as slack develops within the loop slide the hitch away from the anchor object, taking up the slack and enlarging the loop. To loosen, slide hitch toward the anchor object, making the loop smaller and lengthening the standing part.
[edit] Security
Although the three variations are similar they do have distinct properties when put to use. Ashley[6] and others[2][7][8] suggest that #1799 is preferred as being more secure. Either variant of #1800 is also acceptable, especially if ease of adjustment is desired over security.[9] Ashley states the version of #1800 with the reversed concluding hitch has less tendency to twist.[4]
These hitches should not be depended on to hold fast under all conditions. With some particularly stiff or slick modern fibers they can be difficult to make hold at all. Sometimes it can be made more secure by using additional initial wraps and finishing half-hitches.[9] If even more security is needed the Trucker's hitch is quite robust and can be used to produce significantly more tension if required, albeit at the expense of quick adjustability.
[edit] See also
[edit] References
- ^ Mark Adams, Son of a Hitch: A Genealogy of Arborists' Climbing Hitches. http://www.treebuzz.com/pdf/0505_geneology.pdf
- ^ a b c d e Brion Toss, The Complete Rigger's Apprentice (Camden: International Marine, 1998), 54-55.
- ^ Tom Nugent, "Blanketing the Hubble", University of Delaware Messenger, vol. 6, no.3 (1997) http://www.udel.edu/PR/Messenger/97/3/BLANKET.html
- ^ a b c d Clifford W. Ashley, The Ashley Book of Knots (New York: Doubleday, 1944), 304.
- ^ Boy Scouts of America, The Boy Scout Handbook, 11th ed. (Irving: BSA, 1998), 37.
- ^ Ashley, 298.
- ^ Nola Trower, Helmsman Guides: Knots and Ropework (Wiltshire: Helmsman Books, 1995), 31-32.
- ^ Animated Knots by Grog. Rolling Hitch. http://www.animatedknots.com/rollinghitchboating/
- ^ a b Brion Toss, Chapman's Nautical Guides: Knots (New York: Hearst Marine Books, 1990), 30-32.
