Bowline
loop knot
Life-safety notice
TyingPoint's illustrations are for learning. For any life-safety use — climbing, rope access, rescue, or load-bearing rigging — seek qualified in-person instruction, and always inspect and test every knot before you trust your weight (or anyone else's) to it.
The bowline's name comes from square-rigged sailing ships, where a "bow line" ran forward from the leading edge of a square sail to the bow to keep the sail's edge from luffing when the ship sailed close to the wind. The knot that held that line under load needed one specific property no other simple loop offered: it had to stay put while under heavy strain, yet come apart by hand the moment the strain was gone. That single trait is why sailors have called it "king of the knots" for at least two centuries and why it remains the default fixed loop taught in sea scouts, sailing courses, and search-and-rescue training today.
Sailing manuals as far back as Darcy Lever's 1808 The Young Sea Officer's Sheet Anchor already treat the bowline as standard rigging knowledge, and Clifford Ashley's 1944 reference catalogued more than a dozen bowline variants - evidence of how much sailors experimented with the same basic loop to address its one real weakness. In natural fiber rope such as manila or hemp, friction between the strands is high enough that the knot rarely needs a backup; it was specifically the twentieth-century shift to slicker synthetic cordage that turned the bowline's slow-loosening tendency from a minor curiosity into a documented safety concern serious enough to change how sailing and rescue organizations teach it.
Mechanically, the bowline is a interlocking-loop knot: a small loop (often taught as the "rabbit hole"), a working end that comes up through it ("the rabbit"), goes around the standing part ("around the tree"), and back down the same hole ("back into its hole"). Because the load is carried by the loop pinching the crossing turn rather than by friction between parallel wraps, the knot doesn't bind up under tension the way a clove hitch or constrictor does - it can be shaken loose the instant the rope goes slack, which is exactly the point.
That same looseness is the bowline's real weakness. Under repeated load-release cycles - a boat surging at anchor, a rescue line being bounced - the knot can slowly walk and capsize into an unreliable shape, especially in slippery modern rope. This is documented, testable behaviour, not folklore, and it's the specific reason any life-safety use of a bowline calls for a backup knot on the tail.
How to tie the Bowline
Lay the standing part across your palm and form a small loop (the 'hole') a hand's width from the end, with the working end crossing on top.
Strength & security
Approx. strength retained: 60-70%
The bowline holds its shape well under a steady, single-direction pull, but the three-part construction can work loose over repeated slack-tight cycles - the reason sailors and rescue teams routinely back it up with a double overhand (stopper) on the tail rather than trusting the bare knot on a life-critical line.
Cautions: Avoid the plain bowline on stiff, slick modern cordage (Dyneema, some braided synthetics) where it can shake loose without a load on it; it is not the right choice for joining two rope ends of different materials, and it should not be tied with too short a tail.
Alternatives
- Figure-Eight Loop
Doesn't capsize under repeated shock-loading the way a bowline can, which is why many climbers tie in with a figure-eight instead - though it jams much harder and is slower to untie after a big fall.
- Bowline on a Bight
Gives two equal loops instead of one, useful when a seat or a two-point anchor is needed and there's no free end to work with.
FAQ
Is the bowline strong enough for climbing?
It's still used as a tie-in knot by some climbers, but it must be backed up with a stopper knot, because an unbacked bowline can work loose over repeated falls in a way a figure-eight loop generally doesn't.
Why does the bowline sometimes come undone on its own?
A bare bowline relies on the loop staying pinched shut; on stiff or slick rope, or under cycles of slack and tension with no load on the standing part, that pinch can walk loose. A stopper knot on the tail removes the risk.
What does 'dressing' a bowline mean?
Arranging the three rope parts so they run parallel and untwisted before the knot is loaded - a loosely dressed bowline is measurably weaker and more prone to slipping than a properly dressed one.