More details about the The Double Fisherman's (Grapevine) Knot
Structure: The Double Fisherman's, or Grapevine, Bend (ABOK # 294, p 50.) consists of two double overhand knots (on right), each tied round the other standing end. However, because it is created around another line, this structure may not be obvious.
Safety - Use Triple: For load-bearing using modern high modulus ropes such as Spectra, Dyneema or Kevlar/Technora, use a Triple Fisherman's (on left). In each stopper knot the rope is passed around a third time before being threaded back through the loops. The triple, or even quadruple, version is also used by fishermen to join two lengths of fishing line.
Uses: The Triple Fisherman's Bend is the way to form a Prusik Loop and is an excellent and reliable way of joining two climbing ropes. It can be used for a full rope-length abseil; after which it is still possible to retrieve the rope.
Inspection: The Double Fisherman's is not complicated. Nevertheless, it can be tied wrongly and then fail. If you tie it and your life depends on it, inspect it carefully. If someone else ties it, inspect it extremely carefully.
Comparisons: The Double Fisherman's is a reliable, compact knot less likely to get stuck when retrieving an abseil, but somewhat harder to undo than the Figure Eight Bend.
- The Figure Eight Bend is bulkier - especially when stopper knots are added for safety. It is however, relatively easy to teach and inspect.
- The Overhand Knot Join (an overhand knot tied with both ends together with lengthy ends) is the rope join least likely to get stuck (picture on right). This is because the two ropes exit the knot at the same point and, therefore, pass over an obstruction relatively easily. Its use as a join is approved and recommended by the International Federation of Mountain Guides Associations (IFMGA). For additional safety it is also used with an extra overhand knot in the tails. Some authorities call this the "Euro Death-Knot" (EDK) supposedly because it was assumed (seemingly wrongly) to roll-over and fail. EDK seems a more useful label to apply to the figure eight:
- The "Euro Death-Knot" (EDK) has been appropriately used to describe the figure eight where the two ends exit the knot together - a figure eight version of the overhand knot join above. This version of a figure eight join fails by rolling over even when the ends are long! It has been associated with a number of deaths, and is deliberately not illustrated here.
Both these knots have been extensively reviewed and tested by Thomas Moyer who applies the term EDK to both the overhand and the figure eight versions.