How to Tie the Somerville Bowline
Usage
The Somerville Bowline is a single-column tie: a fixed, non-constricting loop formed around a single object or limb. It comes from the modern rope-art (Shibari) community, where it is a standard cuff at the start of a new rope. Its two defining tricks: it can be tied even when the standing part of the rope is already fixed, and it can be released from either end.
Why Learn the Somerville Bowline?
Most fixed loops, like the classic bowline knot, are threaded — you have to pass a free end through somewhere. The Somerville Bowline is a locked cuff instead: you can form it when the trailing end is already tied off, an earlier tie-off point can be released without disturbing anything tied further down the same rope, and the loop keeps its shape — "non-collapsible" — even when tension shifts direction.
Common Uses
Specialty Rope Work
- A non-constricting single-column cuff around a limb at the start of a new rope — its home use in the rope-art world.
- Progressive tie-offs: freeing an earlier anchor point without undoing anything tied later on the same line.
Utility (Everyday Life)
- Making a fixed loop when you do not have access to both rope ends.
- A releasable, non-constricting cuff under steady one-directional tension.
Other Names
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Notable Features
- Ties with a Fixed End: No tail has to pass through a bight, so it can be formed when the standing end is already anchored.
- Releases from Either End: An earlier tie-off frees cleanly without disturbing rope tied further along the line.
- Non-Collapsible: The two wraps and locked bight hold their shape when tension shifts or arrives from the wrong direction.
- Compact and Fast: "Ultra fast to tie" once learned, per its canonical teaching source.
Similar Knots
Single Column Tie (basic, collapsible) vs. Somerville Bowline
- Advantage: Easier for beginners and gives up easily when you want it undone.
- Disadvantage: Can collapse when tension shifts direction — the exact failure the Somerville was invented to fix.
Single Column Tie (Quick Release) vs. Somerville Bowline
- Advantage: Keeps a draw-bight for fast release even while the rope is still under tension.
- Disadvantage: Less secure than the Somerville's locked, non-collapsible cuff.
Carrick Bend vs. Somerville Bowline
- Advantage: The Carrick Bend is the right choice when the job is joining two rope ends together.
- Disadvantage: It is a bend, not a loop — it cannot serve as a single-column cuff.
Security Level
Community consensus across its teaching sources rates the Somerville Bowline as non-collapsible and, in Crash Restraint's words, "extremely secure" — stable even when tension arrives from shifting directions, and used to carry real body weight in advanced rope work. That confidence comes entirely from practitioner consensus, with no published strength or load testing.
Downsides
- Hard to Release Under Load: It tightens under tension and is near-impossible to undo while loaded — slack the rope first. The Slipped Somerville Bowline variant answers this with a quick-release bight.
- No Test Data: Despite bodyweight-bearing use, there is no published strength or load testing for this knot.
- Direction Matters: Tightened in the wrong exit direction, the lock presses uncomfortably into the limb or object.
- Niche: Essentially undocumented outside the rope-art community.
Structure
The rope makes two wraps around the column, the wraps are nipped together leaving a bight sticking out, and a thrown loop locks that bight in place. Bear Essentials' cuff-not-eye rule sums it up: the Somerville Bowline is a locked cuff, not a threaded eye — nothing has to pull through from a free end, which is why it ties with a fixed standing end, releases from either end, and bites down harder instead of letting go under load.
History
Unusually for a knot, the Somerville Bowline has a clean paper trail: it was worked out around 2009 by a San Francisco rope teacher known online only as "Topologist," and the canonical write-up appeared on Crash Restraint in 2010, then spread internationally. No source explains the name; it does not appear in the Ashley Book of Knots, which predates it by some 65 years.
How to Tie a Somerville Bowline
The trickiest part, per its original teaching source, is forming the loop correctly on top of the cuff. The Knot IQ app lets you rotate the Somerville Bowline in 3D and step through that loop formation one move at a time until it clicks.
Step 1
Wrap the rope twice around the column (the limb or object) — at least two full wraps.
Step 2
Nip all the wraps together, crossing the rope over itself at the wrap point and leaving a bight sticking out.
Step 3
Throw a loop over the protruding bight — form it on a middle finger in the gap between the rope lines and the column — and pinch everything together.
Step 4
Push the bight over and fish it through the loop you just made, passing once over the tails.
Step 5
Pull the tails to tighten and collect the slack. Watch the exit direction — bring the rope down and through so the lock tightens away from the column, not into it.
How to Undo the Somerville Bowline
Step 1
Take all tension off the rope — the knot will not release while loaded.
Step 2
Lift the bight back through from under the knot, the way it was formed, and it opens smoothly.
Step 3
Because it releases from either end, you can free this cuff without disturbing rope tied further along the same line.
FAQ
Can you untie a Somerville Bowline while it's under tension?
Not the base form — it tightens under tension and is near-impossible to release loaded. Slack the rope first, then it opens smoothly. If you need to release while still loaded, tie the Slipped Somerville Bowline, which keeps a quick-release bight.
Why is it called "non-collapsible"?
Its two wraps spread pressure and the locked bight holds them closed, so the cuff keeps its shape even when tension shifts or comes from the wrong direction — unlike the collapsible square-knot-style single column it was designed to improve on.
Is the Somerville Bowline the same as a Carrick Bend?
No. A carrick bend joins two rope ends; the Somerville Bowline is a single-column loop tied around a limb or object. Some rope communities loosely share the name because the two locks look similar, but they do different jobs.
What rope should I practice it on?
Any soft, grippy rope works for learning — traditionally natural fibre, sitting slightly looser on slick synthetics. The practice cord in our Knot Tying Kit is fine for drilling the loop formation, but it is practice cordage only — not rated for supporting a person or any load-bearing use.
Important Notes on Safety
Two cautions matter with this knot. First, it may tighten under tension and is near-impossible to release while loaded — never rely on it where release under load matters; slack the rope first, or use the Slipped Somerville Bowline. Second, its bodyweight-bearing reputation rests on practitioner consensus only, with no published strength or load testing, so treat any load-bearing use as unverified. Tie it in the correct exit direction ("down and through") or the lock compresses into the limb — a comfort and circulation concern. One uncorroborated community report claims it can cinch like a slipknot, contradicted by the broader non-collapsible consensus taught in curricula such as Rope Bite Pgh's Rope Fundamentals I Notes. Learn it with slack practice rope before trusting it with anything that matters.
