What is a double fishermans knot used for?

• A. Used to bind two ropes of the same diameter together, not load bearing, must use the same diameter ropes
• B. To join two pieces of webbing
• C. Hauling, ascending, and self-rescue
• D. Used to join two ropes of equal (or slightly unequal) diameter together for load bearing applications

Answer: (D)

Double fisherman's knot is a bend designed to join two ropes. It works best when the ropes have similar diameters because each rope end wraps around the other and the two overhand components lock against one another under load, creating a secure, load-bearing connection. This makes it a common choice for extending rope length or tying two rope ends together when you need a single strong cord for climbing or rescue work. It’s specifically for rope-to-rope joins, not for connecting webbing, and it isn’t the usual choice for hauling or self-rescue setups that rely on other devices or knots. If the diameters differ significantly, the knot can become bulky or slip, so it’s most reliable when the ropes are equal or very close in diameter.