The Fisherman's Bend Hitch — also called the Anchor Bend — is a knot that secures a rope to a ring, spar, or anchor shackle under sustained pull. Its defining feature is the round turn around the object, with the working end then trapped by a half hitch passed through the turn itself, locking the knot against slip when the rope alternately loads and slackens. Sailors use it to bend an anchor warp to the crown ring of a kedge or fisherman anchor, where it holds at roughly 65–75% of the rope's rated breaking strength and resists shaking loose in tidal cycling.
Fisherman's Bend Hitch Interactive Calculator
Vary rope MBS, knot efficiency, and safety factor to see the realistic working load limit at the anchor hitch.
Equation Used
The calculator multiplies the unknotted rope minimum breaking strength by the Fisherman's Bend efficiency, then divides by the chosen safety factor to estimate the allowable working load at the knot.
- Fisherman's Bend is correctly dressed with two flat round turns and a trapped first half hitch.
- Rope MBS is the manufacturer's unknotted minimum breaking strength.
- Efficiency is entered as a percentage and converted to eta = percent / 100.
- Safety factor applies to the final working load limit.
The Fisherman's Bend Hitch in Action
The knot starts with two complete passes of the working end around the ring — that's the round turn. Those wraps spread the load across the ring's bearing surface and absorb the first surge of tension before the knot proper takes over. The working end then comes back across the standing part and passes under both legs of the round turn, forming the first half hitch trapped inside the turn itself. A second half hitch around the standing part finishes the knot and stops the tail flogging loose. That trapped first hitch is what separates the Fisherman's Bend from a plain round turn and two half hitches — it bites into the round turn under load and refuses to back out when the rope goes slack, which is the exact failure mode that kills lesser knots on a swinging mooring.
The geometry only works if the round turn sits flat against the ring with no crossed wraps. If you let the second wrap ride over the first, you create a point load on a single rope diameter and the knot will start to creep under cyclic loading — common when an anchor rode alternately tensions and slackens with wave action. The first half hitch must pass through both wraps of the round turn, not just one. Miss this and you've effectively tied a round turn and one half hitch with a decorative tail, which slips at around 40% of rope MBS instead of 70%.
Failure modes are predictable. On a wet polyester or nylon line, a tail shorter than 8 rope diameters will work loose over 12–24 hours of tidal cycling. On a stiff, glazed-finish polypropylene the round turn won't compress evenly and the knot can roll off the ring under a sharp jerk load. And on undersized cordage relative to the ring bore, the round turn fails to bridge the ring and the half hitches end up doing all the work.
Key Components
- Round Turn: Two full wraps of the working end around the ring or spar. Distributes the initial load across roughly 360° of bearing surface, reducing peak rope pressure and absorbing shock before the locking hitches engage. Wraps must lie parallel and flat — any crossover concentrates load on a single fibre bundle.
- Trapped First Half Hitch: The working end returns across the standing part and is tucked under both legs of the round turn. This is the locking element unique to the Fisherman's Bend. Under load the round turn squeezes this hitch and prevents it backing out when tension cycles, which is what gives the knot its hold on a swinging anchor warp.
- Second Half Hitch: Tied around the standing part above the trapped hitch. Acts as a backup retainer that prevents the tail from flogging free in a seaway. Should sit 3–5 rope diameters above the first hitch to allow the knot to compress without binding.
- Working Tail: Minimum 8 rope diameters long after the second hitch — for 12 mm rope, that's a 100 mm tail. Shorter tails on slick synthetics like polyester will creep loose under tidal cycling. On critical applications, seize the tail to the standing part with whipping twine.
- Standing Part: The loaded leg of the rope leading back to the windlass, samson post, or sailor. Carries the full mooring or towing tension; the knot's job is to transfer that load into the ring without slipping or chafing through under cyclic loading.
Real-World Applications of the Fisherman's Bend Hitch
The Fisherman's Bend earns its keep wherever a rope must attach to a fixed metal ring under sustained, cyclic, often wet load — which describes most of small-craft anchoring and a fair amount of working harbour rigging. You'll see it on cruising yachts, working fishing boats, museum sailing replicas, and traditional rigging schools. It's the knot the Royal Yachting Association teaches for bending an anchor warp to the anchor crown, and the one specified in the Ashley Book of Knots entry #1841.
- Recreational sailing: Bending nylon anchor warp to the crown shackle of a Lewmar Delta or Rocna anchor on cruising yachts in the 8–14 m range.
- Commercial fishing: Securing kedge anchor lines on Cornish crabbers and Scottish creel boats where the rode must survive tidal cycling without inspection.
- Heritage marine: Bending hemp-laid manila warps to fisherman-pattern admiralty anchors on vessels like the SS Great Britain dockside display in Bristol.
- Sail training: Standard knot taught aboard the Tall Ships Youth Trust brigs Stavros S Niarchos and Prince William for emergency anchor work.
- Rigging trades: Used by spar makers and traditional riggers at yards like Spencer Rigging in Cowes when temporarily securing a stay or shroud to a masthead ring during stepping operations.
- Mooring services: Attaching pickup rope pennants to swing-mooring buoy rings in harbours such as Salcombe and Falmouth where lines see twice-daily tidal reversal.
The Formula Behind the Fisherman's Bend Hitch
Knot strength is expressed as a knot efficiency — the percentage of the rope's rated minimum breaking strength (MBS) that the knotted line will hold before the rope fails at the knot. For the Fisherman's Bend on a clean ring with appropriate rope diameter, efficiency sits between 65% and 75%. At the low end of the typical range — old, glazed, or undersized cordage on a slick ring — you're closer to 60%. At the high end — fresh three-strand nylon, well-dressed, on a ring at least 4 rope diameters in bore — you can see 75%+. The sweet spot for a working anchor warp is a fresh nylon laid rope where you'd design around 70% efficiency for a working load calculation.
Variables
| Symbol | Meaning | Unit (SI) | Unit (Imperial) |
|---|---|---|---|
| WLLknot | Working load limit of the rope at the knot | kN | lbf |
| MBSrope | Manufacturer-rated minimum breaking strength of the unknotted rope | kN | lbf |
| ηknot | Knot efficiency factor for the Fisherman's Bend (typically 0.65–0.75) | dimensionless | dimensionless |
| SF | Safety factor applied to working loads (typically 5 for anchoring, 7 for life safety) | dimensionless | dimensionless |
Worked Example: Fisherman's Bend Hitch in a cruising yacht anchor rode
Your sailmaker-turned-rigger workshop in Plymouth is specifying an anchor rode for a Hallberg-Rassy 40 cruising yacht using 16 mm three-strand nylon from English Braids with a published MBS of 49 kN, terminated to the crown shackle of a 20 kg Rocna Vulcan anchor with a Fisherman's Bend Hitch. The owner needs to know the realistic working load at the knot for setting maximum design wind and current loads.
Given
- MBSrope = 49 kN
- ηknot,nominal = 0.70 dimensionless
- SF = 5 dimensionless
Solution
Step 1 — calculate the breaking strength at the knot using the nominal 70% efficiency for fresh laid nylon on a clean shackle ring:
Step 2 — apply the standard 5:1 anchoring safety factor to get nominal working load limit:
Step 3 — at the low end of the typical operating range (old, glazed rope, or rope diameter undersized to ring bore), efficiency drops to 0.65:
That 50 kgf reduction is the difference between holding through a 35-knot squall and dragging at 32 knots on a 40-foot yacht — small numerically, decisive in a real anchorage. At the high end of the range with fresh, well-dressed nylon on a generously sized ring (4+ rope diameters in bore), efficiency reaches 0.75:
The sweet spot is fresh nylon with a properly dressed knot — design to the nominal 700 kgf and you've got headroom on either side without kidding yourself about old rope.
Result
Nominal working load limit at the knot is 6. 86 kN, or about 700 kgf. That's the load you should treat as the design ceiling for sustained anchoring — gusts and snatch loads can momentarily exceed it because the safety factor absorbs them. Across the operating range you're looking at 650 kgf for tired rope at the low end and 750 kgf for fresh, well-dressed line at the high end, so the practical design window sits within roughly ±7% of nominal. If your rode parts at noticeably less than 34 kN in a destructive test, suspect (1) a crossed round turn that point-loaded a single fibre bundle, (2) the first half hitch tucked under only one leg of the round turn instead of both — common with cold hands or thick gloves, or (3) ring bore less than 3 rope diameters, which crushes the rope at the bearing point and drops efficiency below 60%.
When to Use a Fisherman's Bend Hitch and When Not To
The Fisherman's Bend competes with a small handful of knots used for the same job — bending rope to a ring under cyclic load. Each has a real engineering trade in holding strength, ease of untying after load, and how forgiving it is when tied wet, cold, or in the dark.
| Property | Fisherman's Bend Hitch | Round Turn & Two Half Hitches | Bowline through Ring |
|---|---|---|---|
| Knot efficiency (% of rope MBS) | 65–75% | 60–70% | 55–65% |
| Resistance to cyclic slack-load (tidal) | Excellent — first hitch trapped under round turn | Fair — can work loose in 12 hours | Poor — bowline can capsize when shaken |
| Ease of untying after heavy load | Moderate — requires working the trapped hitch | Easy — half hitches break out cleanly | Difficult — bowline jams after shock load |
| Tying complexity (cold/wet hands) | Moderate — 4 distinct steps | Easy — 3 steps, very forgiving | Easy once learned, but error-prone in dark |
| Best application fit | Anchor warp to crown ring, mooring buoy | Temporary tie to bollard or rail | Loop attachment where untying matters more than ultimate hold |
| Performance on slick synthetic rope | Good — round turn provides bite | Marginal — half hitches slip on polyester | Marginal — knot can capsize |
Frequently Asked Questions About Fisherman's Bend Hitch
Polyester double-braid has a much smoother, harder jacket than three-strand nylon, and the round turn doesn't compress and grip the way it does on laid construction. The knot was designed for laid rope — the helical fibre lay actively bites into the ring and the hitches.
If you must use the Fisherman's Bend on braided polyester, add a third wrap to the round turn (making it a riding turn), seize the tail to the standing part with sail twine, and inspect after the first 24 hours. For permanent polyester rodes, most riggers move to a thimble splice in the rope eye and a shackle to the anchor — the splice retains 90%+ MBS and removes the slip question entirely.
Minimum ring inside diameter should be 4× the rope diameter for full knot efficiency, and absolutely no less than 3×. For a 16 mm warp, that's a 64 mm preferred bore, 48 mm absolute minimum.
Below 3× the round turn can't lie flat — the second wrap rides up on the first, the rope is forced into a tight bend radius that locally crushes the fibres, and your efficiency falls into the 50–55% range. If your anchor shackle bore is too small, fit a properly sized stainless thimble between the rope and the shackle and tie the bend to the thimble's larger bearing surface.
They're the same knot. Ashley lists it as #1841 under Anchor Bend, and the Royal Yachting Association uses Fisherman's Bend in its training material. Some older texts distinguish them by whether the first half hitch is locked through the round turn or merely thrown over the standing part outside the turn — the locked version is the one you want, because the unlocked version is essentially a round turn and two half hitches with a different name and the same lower holding strength.
If a source describes the knot without the trapped first hitch, it's not the working knot — it's a weaker variant that shouldn't be used on an anchor.
For a permanent rode you intend to leave in service for a season, splice and shackle wins on every measurable metric. A properly tucked three-strand eye splice retains 90–95% of rope MBS versus the Fisherman's Bend's 70%, doesn't need re-dressing after a heavy blow, and the load path through a galvanised D-shackle is geometrically cleaner than rope-through-ring.
The Fisherman's Bend's value is in the field — when you need to bend a fresh warp to a borrowed anchor at 0200 in a rising onshore wind, you can tie it in 30 seconds with cold hands. Keep it in the toolkit for that, and splice your primary rode at the bench.
Two causes account for nearly all of these cases beyond the obvious tying errors. First, tail length: a tail shorter than 8 rope diameters (so under 100 mm on 12 mm rope) will work back through the second half hitch as the rope alternately tensions and goes slack on the tide. Re-tie with a 150 mm minimum tail.
Second, the rope may be over-stiff — old, sun-glazed, or salt-crystallised line loses the suppleness needed for the round turn to settle. Soak the working end in fresh water for an hour before tying, or replace the rope. A diagnostic check: if the round turn doesn't lie flat against the ring under hand tension before you load it, it won't lie flat under load either, and the knot will creep.
It handles shock load well, which is part of why it's the traditional anchor knot — anchor rodes routinely snatch in waves and the knot is designed for that duty cycle. The round turn absorbs the first peak and spreads it over the ring's full bearing surface before the hitches see the load.
What it doesn't tolerate is shock loads on a knot that's been allowed to go fully slack and re-tension repeatedly without re-dressing — over many cycles the trapped hitch can migrate. On a snubber bridle subject to constant wave action, inspect the knot every 24 hours and re-dress it if the round turn has loosened. For racing or storm conditions, splice the bridle eye instead.
References & Further Reading
- Wikipedia contributors. Anchor bend. Wikipedia
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