Joining Knots
Part of Knots and Cordage
Joining knots (bends) connect two separate ropes into one. In survival, your rope is never long enough. Knowing which bend to use for which combination of materials is the difference between a secure connection and a catastrophic separation.
Why Joining Knots Are Critical
Rope runs out. Cordage breaks. You find three short pieces when you need one long piece. You scavenge rope from different sources — paracord from a backpack, vine cordage you twisted yourself, a strip of rawhide from a deer hide, electrical wire from a ruined building. These materials have different diameters, different textures, different stiffness levels. A joining knot must grip despite these differences.
The most common mistake in survival ropework is using a square knot (reef knot) to join two ropes end-to-end. The square knot is a binding knot — it holds two ends of the same rope around a package or bandage. Used to join two separate ropes under load, it will slip, capsize, and separate. People have died because of this confusion.
This article covers the joins that actually work.
The Sheet Bend: Your Primary Join
The sheet bend is the standard knot for joining two ropes, especially ropes of different diameters or materials. It is fast, reliable, and easy to inspect.
How It Works
The sheet bend functions by creating an interlocking friction grip. The thicker rope forms a bight (U-shape), and the thinner rope threads through and wraps around it. Under load, the thinner rope cinches against itself and the bight, creating more friction the harder you pull.
Tying the Sheet Bend
Step 1. Form a bight (U-shape) in the end of the thicker rope. Hold it in your non-dominant hand with the open end pointing up.
Step 2. Pass the thinner rope up through the bight from underneath.
Step 3. Route the thinner rope around the back of the bight, wrapping around both legs of the U.
Step 4. Tuck the thinner rope under its own standing part (the part leading back to the thinner rope’s load), but over the bight. The thinner rope’s working end should exit on the same side as the bight’s working end.
Step 5. Pull all four strands to tighten: both standing parts and both tails.
Critical Detail
Both working ends (tails) must exit on the same side of the knot. If they exit on opposite sides, you have tied a left-handed sheet bend, which is significantly weaker and can slip under cyclic loading.
The Double Sheet Bend
For ropes of very different diameters (greater than 2:1 ratio), slippery synthetic rope, or life-critical applications, add an extra wrap:
After Step 3, instead of tucking under immediately, wrap the thinner rope around the bight a second time, then tuck under its own standing part.
The double sheet bend provides approximately 30% more holding power than the single version.
| Rope Combination | Single Sheet Bend | Double Sheet Bend |
|---|---|---|
| Same diameter, same material | Excellent | Overkill |
| Different diameter, same material | Good | Recommended |
| Same diameter, different materials | Good | Recommended |
| Different diameter, different materials | Fair | Required |
| Wet or slippery rope | Poor | Minimum; add stopper knots |
| Plant cordage to synthetic | Fair | Required |
The Fisherman’s Knot (Angler’s Knot)
The fisherman’s knot joins two ropes of similar diameter by tying each rope around the other with an overhand knot. The two overhand knots slide together and lock under load.
When to Use It
- Joining two ropes of the same or very similar diameter
- Making a loop from a single length of cord (tie the two ends together)
- Fishing line joins (hence the name)
- Situations where a very compact knot is needed
Tying the Fisherman’s Knot
Step 1. Lay the two ropes parallel, overlapping by about 30 cm (12 inches), with the working ends pointing in opposite directions.
Step 2. Take the working end of Rope A and tie an overhand knot around Rope B’s standing part. Do not tighten fully yet.
Step 3. Take the working end of Rope B and tie an overhand knot around Rope A’s standing part. Do not tighten fully yet.
Step 4. Pull both standing parts simultaneously. The two overhand knots will slide together and lock against each other.
Step 5. Tighten each overhand knot individually by pulling its working end against its own standing part. Then pull the standing parts again to snug the knots together.
Permanent Knot
The fisherman’s knot is extremely difficult to untie after being loaded. Treat it as semi-permanent. If you need a join you can release easily, use a sheet bend instead.
The Double Fisherman’s Knot
Replace each overhand knot with a double overhand knot (wrap twice around the other rope before tucking through). This creates the strongest rope-to-rope join available, retaining approximately 65-70% of the weaker rope’s strength.
When to use: Climbing applications, rescue lines, any situation where the join must not fail and you do not need to untie it.
| Property | Sheet Bend | Fisherman’s | Double Fisherman’s |
|---|---|---|---|
| Retained strength | ~45-50% | ~55-60% | ~65-70% |
| Works with different diameters | Yes (excellent) | No (similar only) | No (similar only) |
| Easy to untie | Yes | Difficult | Nearly impossible |
| Compact profile | Moderate | Small | Small |
| Speed to tie | Fast | Moderate | Slow |
| Inspection ease | Easy | Moderate | Moderate |
The Water Knot (Ring Bend)
The water knot joins flat materials — webbing, strips of fabric, rawhide strips, bark strips — where round-rope knots would slip.
Tying the Water Knot
Step 1. Tie a loose overhand knot in the end of one strip.
Step 2. Thread the other strip’s working end into the overhand knot, retracing the knot’s path exactly but in the opposite direction.
Step 3. Pull all four strands to tighten. The result is two overhand knots nested together.
When to use: Joining flat webbing, fabric strips, bark cordage, rawhide lacing, or any flat material where the sheet bend would roll and slip.
The Zeppelin Bend: The Ideal All-Rounder
Less well-known than the sheet bend, the Zeppelin bend is arguably the best general-purpose joining knot. It holds securely under load, unties easily after loading, works with ropes of similar diameter, and never jams.
Tying the Zeppelin Bend
Step 1. Form a loop in each rope end, as if starting to tie a figure-eight. Lay them on top of each other so the loops overlap, each rope’s working end pointing in opposite directions.
Step 2. Take Rope A’s working end and pass it through both loops from the top.
Step 3. Take Rope B’s working end and pass it through both loops from the bottom (opposite direction of Rope A).
Step 4. Pull both standing parts to tighten.
The Zeppelin bend is symmetrical, clean, and easy to verify. If your rope supply is consistent (same type, same diameter), this is the join to learn after the sheet bend.
Choosing the Right Join
| Scenario | Best Knot | Why |
|---|---|---|
| Two ropes, different diameters | Double sheet bend | Designed for diameter mismatch |
| Two ropes, same diameter, temporary | Sheet bend or Zeppelin | Easy to untie |
| Two ropes, same diameter, permanent | Double fisherman’s | Strongest possible join |
| Fishing line to fishing line | Fisherman’s knot | Compact, slides through guides |
| Flat webbing to flat webbing | Water knot | Only option for flat material |
| Wet or slippery ropes | Double sheet bend + stopper knots | Maximum grip on low-friction materials |
| Plant cordage to plant cordage | Sheet bend | Rough fibers grip well |
| Cordage to scavenged wire | Double sheet bend | Handles stiffness mismatch |
Testing Your Joins
Every joining knot should be tested before trusting it with a critical load:
Step 1. Tie the knot and dress it neatly (no crossing or overlapping strands within the knot body).
Step 2. Pull firmly on both standing parts with your hands. Use your body weight if needed. The knot should not slip, deform, or show any movement.
Step 3. Check that both tails are at least 10-15 cm (4-6 inches) long. Short tails can pull through under shock loading.
Step 4. For critical applications, hang a progressively heavier load from the join. Start with 5 kg, then 10, then 20. Watch for any slippage.
Step 5. After loading, inspect the knot again. Has it tightened further? Has the profile changed? A knot that changed shape under load may be approaching failure.
Common Mistakes
- Using a square knot to join two ropes under load. The square knot is not a joining knot. It capsizes and separates. This mistake kills people.
- Joining ropes of very different diameters with a fisherman’s knot. The overhand knots cannot grip properly when the diameter mismatch is large. Use a sheet bend.
- Leaving short tails. Any tail under 10 cm is a failure risk. Longer is always safer.
- Not dressing the knot. A sloppy knot with twisted or overlapping strands is weaker than a neatly dressed one. Take five extra seconds to align the strands.
- Failing to test. A knot you have not tested is a knot you cannot trust.
Key Takeaways
- The sheet bend is your default rope join. It handles different diameters, different materials, and unties easily. Double it for critical loads or slippery materials.
- The double fisherman’s knot is the strongest join but is nearly impossible to untie. Use it when the connection is permanent.
- Never use a square knot to join two ropes under tension. It will fail.
- The water knot is the only reliable join for flat materials — webbing, bark strips, rawhide.
- Always leave long tails and always test the knot before loading. These two habits prevent the majority of knot failures in the field.