How to Tie the Double Alpine Butterfly (Bi-Directional Loop)

Usage

The double alpine butterfly puts two independent, fixed loops mid-rope, dressed to come out opposed — one on each side of the mainline, at roughly 90 degrees to it. That opposed dressing is the whole point: it gives you attachment points on both sides of a running line, from a single knot, with no rope ends involved. It's a direct derivative of the single alpine butterfly knot, doubled and set counter-directionally.

Each loop uses the same nipping-collar mechanism as the single butterfly, tied and dressed separately, so loading one loop doesn't milk rope out of, or collapse, the other. That independence is what lets the knot take load from either loop, either end, or between the two ends with the loops left hanging free.

Why Learn the Double Alpine Butterfly?

Most mid-line loop knots give you one attachment point. This one gives you two, on opposite sides of the rope, without ever untying or re-threading an end — useful anywhere a line needs to serve people or gear approaching from both directions. It's also a fast way to bracket a damaged section of rope between two loops, keeping that section out of the load path.

It's a specialist's knot, not an everyday default — the single alpine butterfly remains the better choice whenever one loop is enough. Learn the double once you already have the single butterfly comfortable, since the tying motion and dressing habits carry straight over.

Common Uses

Search and Rescue

• Clip-in points on a shared safety line — a line of hikers or workers hooking on along one rope, each loop independently loadable without disturbing the others.

Climbing and Rigging

• Creating multiple secure mid-line attachment points where the rope's ends aren't accessible.
• More roll-resistant than a bowline on a bight or a figure-8 double loop, which can both roll over under an off-angle pull.

Utility

• Distributing load across two loops mid-rope, or isolating a damaged section of rope by bracketing it between the two eyes.
• Mainline rigs that need attachment points on both sides of the line — the counter-directional dressing is what makes this possible; a same-direction double loop does not deliver it.

Arborists have also demonstrated it for tree rigging and dual attachment points in load distribution — a credible specialist use, though it isn't cited in any formal arborist rigging standard, so treat it as a specialist demo rather than an endorsed practice.

Other Names Double Alpine Butterfly Loop Double Lineman's Loop Double Harness Loop Twin Loop Knot Category Climbing Search and Rescue (SAR) Utility (Everyday Life)

Notable Features

• Tied in the Bight: No access to either rope end is needed — both loops form mid-rope, which is exactly why it works on long lines with people or gear already attached past the knot.
• Non-Collapsing: Each loop keeps its own separate nipping collar, so loading one eye doesn't steal slack from, or collapse, the other.
• Bi-Directional: Dressed opposed at roughly 90 degrees, the pair presents a connection point on each side of the mainline — few mid-line loop knots do this.
• Four-Way Loadable: Load safely from both loops and ends together, from either loop to either end, end-to-end with the loops free, or loop-to-loop with the ends free.

Myth-Bust: The Half-Twist Isn't a Mis-Tie

It's a natural assumption that the double should take a carabiner cleanly, the same way the single alpine butterfly does. It doesn't — not in the traditional double-eye geometry. A knot tyer on the IGKT forum proved it: tie the traditional double butterfly, clip in a carabiner, then untie the knot back down to a single butterfly without ever opening the carabiner gate. The ring stays entangled the whole way, which shows the half-twist in the eye legs is unavoidable in this geometry — not a tying error. If you need a twist-free ring seat, that calls for a structurally different double-eye variant, not a re-dress of this one.

Similar Knots

Alpine Butterfly Knot vs. Double Alpine Butterfly

• Advantage of the double: Two independent loops instead of one, with attachment points on both sides of the mainline — the single butterfly can't do that.
• Disadvantage of the double: Slower to tie and dress, and the traditional geometry's weak-side eye can jam hard after heavy shock loads, unlike the single loop's famously easy untie.

Figure-8 Double Loop (Bunny Ears) vs. Double Alpine Butterfly

• Advantage of the double alpine butterfly: Better roll-resistance mid-line — the figure-8 double loop and bowline on a bight can both roll over under an off-angle pull.
• Disadvantage of the double alpine butterfly: Puts its loops on opposite sides of the line rather than the same side, so it doesn't suit a same-side two-bolt anchor the way the figure-8 double loop does.

Spanish Bowline vs. Double Alpine Butterfly

• Advantage of the double alpine butterfly: Purpose-built for a loaded mainline that keeps running past the knot, with loops that stay independent under load.
• Disadvantage of the double alpine butterfly: The Spanish Bowline's two adjacent, adjustable loops suit an improvised rescue seat around a person — a job the opposed-loop butterfly isn't shaped for.

Security Level

Each loop is a full alpine-butterfly nipping collar, the same mechanism behind the single loop's reputation for holding under load, and every source agrees the loops won't collapse under normal use. It scores well for security, but with a real caveat: the bi-directional function is entirely dressing-dependent. Uneven dressing lets one collar take more than its share of the load, and the traditional geometry's weak-side eye is the documented point that jams first — field-pulled to roughly 400 kg before it began binding hard, versus an improved variant that stayed easy to untie past 1,000 kg (about 880 lb / 2,200 lb). Those are one enthusiast's field pulls with a hand dynamometer, not lab-calibrated data, so treat the numbers as a directional comparison, not a rated strength figure. Stiff rope worsens the jam risk under shock load.

Downsides

• Careful Dressing Required: The opposed 90-degree set is the function — mis-dress it same-direction and you still have two loops, but you've lost the bi-directional capability without any obvious visual sign.
• Jams Under Heavy Shock Load: The traditional double-eye geometry's weak-side eye can bind hard after a heavy or shock load, especially in stiffer rope.
• Fiddlier Than the Single Loop: A fourth palm wrap, a second collar to dress, and the counter-directional set add real time and a few extra ways to get it wrong versus the already-fiddly single butterfly.
• Not a Life-Safety Tie-In: No source positions this as a primary harness attachment for climbing. It's a utility, SAR, and rigging clip-in knot — use a discipline-certified tie-in knot for primary life-safety attachment instead.

Structure

The double alpine butterfly buys independence at the cost of twist. Each loop keeps its own separate nipping collar, so the two eyes are mechanically independent — which is exactly why the knot can promise safe loading from four different directions. Setting the collars opposed points them to opposite sides of the mainline, giving the pair a connection face on each side. The trade-off shows up in the traditional geometry's eye legs, which must carry a half-twist that becomes a stress concentrator — it's the reason the weak-side eye is the part that jams first under heavy load, while the single alpine butterfly stays famously easy to untie.

History

No pre-modern source documents the double-loop form directly — it postdates the single alpine butterfly's early-1900s appearances and has no Ashley Book of Knots plate or number of its own. Modern references (AnimatedKnots, Wikipedia, The Knots Manual) treat it as a derivative of the single alpine butterfly / lineman's loop and the harness/artilleryman's loop family. The most substantial documented discussion of how it's actually tied comes from a 2022 IGKT knot-tying forum thread, which worked out that at least two structurally distinct double-eye geometries exist under the same name, proved the traditional geometry's half-twist is unavoidable, and ran the only field jam-resistance tests located for this knot.

How to Tie a Double Alpine Butterfly

This is the hand-winding method, the same family of motion as the single alpine butterfly with one extra wrap and a second loop to dress. Practice it on a length of 750 lb paracord until the wrap-and-lift becomes automatic.

Step 1

Wrap the rope across your open palm four times.

Step 2

Position turns 2 and 3 — the two middle wraps — near your fingertips.

Step 3

Pick up turns 2 and 3 and tuck them under the other two turns.

Step 4

Slide the resulting loops off your hand.

Step 5

Tighten by pulling on the loops and both standing ends. Dress each collar separately so both loops sit clean, then set them opposed — one emerging on each side of the mainline, at roughly 90 degrees to it. Snug each collar in turn, evenly, so neither one steals slack from the other. A half-twist in the eye legs at this point is normal for the traditional geometry, not a mis-tie.

Loop size locks in once the collars set, so size both loops during the wrap in Step 1 — before any tightening. This is the step most hand-wrap tutorials rush past, and it's the easiest place to end up with a lopsided pair.

If the wrap-and-lift is hard to picture from text alone, the Knot IQ app shows this knot in full 3D — useful here specifically because the counter-directional dressing is hard to judge from flat diagrams, and getting the 90-degree opposition right is the difference between a bi-directional knot and just two ordinary loops.

How to Untie a Double Alpine Butterfly

Remove all load from both loops and both ends first. Flex the knot body to break each collar's set, the same motion used on the single butterfly, done once per collar. Peel each collar back off its eye legs, working the weak-side eye first if the knot has carried a heavy load. The structure resolves back through a single-butterfly stage as it comes apart. After a genuinely heavy load, expect the traditional geometry's weak-side eye to need real effort — field pulls show it can take a couple of minutes per side once loaded past roughly 1,000 kg (2,200 lb).

FAQ

What makes the double alpine butterfly bi-directional?

Its two loops are dressed opposed — one emerging on each side of the mainline at roughly 90 degrees — so you get attachment points on both sides of the rope. Dress both loops the same direction instead and you still have two loops, but you lose the both-sides capability that makes this knot worth tying over a plain double loop.

I see a half-twist in the eye legs — is that a mis-tie?

No. In the traditional double-eye geometry a half-twist in the eye legs is unavoidable, not a tying error. It was demonstrated on the IGKT knotting forum by inserting a carabiner into a finished double butterfly, then untying the knot back down to a single butterfly without ever opening the carabiner gate — proof the twist is baked into the structure.

How many ways can you safely load a double alpine butterfly?

Four, per AnimatedKnots' documented spec: from both loops and both ends together; from either loop to either end; between the two ends with the loops hanging free; or between the two loops with the ends hanging free.

Can you tie it mid-rope with no access to either end?

Yes. It's tied in the bight, meaning you never need a free end — which is exactly why it works as a clip-in point along a shared safety line where the rope keeps running past the knot in both directions.

Important Notes on Safety

• Not a life-safety tie-in. No source endorses the double alpine butterfly as a primary harness attachment for climbing. It reads clean at a glance even when mis-dressed — a same-direction double looks nearly identical to the correct counter-directional form — which is a poor inspectability profile for a life-safety knot. Use a discipline-certified tie-in knot for primary attachment; the single alpine butterfly or a Spanish bowline are the better fits for that role.
• Dress the opposition every time. The 90-degree opposed set is not cosmetic — it's the entire function. Check it before loading, not after.
• Heavy shock loads can jam the weak-side eye, especially in stiff rope. This is a utility and rigging risk, not a strength failure — the knot holds; it's the untying afterward that costs you time.
• Watch for lookalikes. It shares the informal nickname "Alpine Bunny Ears" with the unrelated figure-8 double loop, and the traditional vs. girth-hitch double-eye geometries look nearly identical when tied — confirm which one a given tutorial actually taught you before you rely on its behavior.