Splice or knot? That’s the first question you should ask anytime you need to put a loop, eye or join in a rope. The short answer: if it’s going to carry real load for any length of time, splice it. A knot is quick to tie and easy to undo, but the sharp bend it puts in the rope can cut its strength by up to 60%, and it’s not built to stay put under repeated loading. A splice avoids that trade-off entirely, which is why it’s the standard wherever a rope has to hold for good. A splice is always recommended over knotting.
Splicing vs Knotting
A knot works by bending the rope sharply around itself, and that bend is exactly what weakens it. Southern Ropes’ own testing puts it plainly: a properly tied knot can cut a rope’s strength by up to 60%. Independently published knot strength data backs this up: a bowline typically holds onto around 60% of a rope’s original strength, and a plain overhand or figure-8 knot can drop closer to 45%.
A splice doesn’t bend the rope’s structure the same way. It works the load back into the rope itself, tucking strands or fibres so they share the load the way the rope was actually built to. Done properly, a splice typically retains 90% or more of the rope’s rated strength, which is why every rated rigging, mooring or lifting eye on commercial gear is spliced, not knotted.
The trade-off is effort. A knot takes seconds and can be untied. A splice takes skill, time or a professional service, and it’s permanent. For a quick, temporary tie-off, a knot’s still the right call. For anything load-bearing, splice it. If you need to temporarily join two lengths of rope, Southern Ropes recommends using their soft shackles.
When to Splice a Rope
Splicing makes sense any time you need:
- A permanent eye or loop. Mooring points, lifting eyes and tow points all need hardware permanently attached to the rope, that’s the job an eye splice does.
- To repair localised damage. Cut out the damaged section and re-splice the ends, provided the rest of the rope is sound.
- To join two lengths of rope. A proper splice keeps far more strength than a knot joining two ropes would.
- A smooth profile through hardware. A splice runs through a block, sheave or fairlead far more cleanly than a bulky knot, which can jam or chafe.
Splicing isn’t always the answer though. Don’t splice if:
- The damage is spread across the rope rather than sitting in one section.
- The core is compromised. On a double braid or kernmantel rope, a damaged core can’t be fixed by re-splicing the cover alone.
- There’s internal powdering, fibre dust, or the rope has failed inspection on other grounds.
- It’s a life-safety rope, and the manufacturer or standard in use doesn’t approve field splicing.
When in doubt, that’s a retirement decision, not a splicing one.
Types of Splices
Which splice you use depends entirely on the rope’s construction.
Eye splice
The most common splice there is, it forms a permanent loop by tucking the rope’s own strands back into itself. Used across almost every construction, from 3-Strand Polysteel to double braid.
3-strand splice
Built for twisted rope like 3-Strand Polysteel, or natural fibre rope such as Manila and Hemptex. The strands are unlaid and tucked back through the standing part in sequence, slower than other splices but forgiving to get right.
12-strand (plaited) tuck splice
Used on single braid and plaited constructions like 12-Strand Polysteel or Super-12®. It’s one of the most secure splices available, the strands lock into the braid pattern rather than just sitting inside it.
Double braid splice
The most technical of the lot, since the cover and the core get worked separately, then buried one inside the other so both carry load.
Soft shackle
Not a splice type on its own so much as a splice application, a soft shackle is a loop of single braid (usually HMPE) closed with a splice and secured with a locking knot rather than metal hardware. Lighter and gentler on connected gear than a steel shackle, and increasingly common in rigging, towing and marine use, we carry a soft shackle range already made up.
Back splice, short splice and long splice
Less common on synthetic rigging rope, but worth knowing.
- A back splice finishes a rope end without an eye, though it bulks up the end, so it’s rarely used through hardware.
- A short splice joins two ropes at close to full strength but increases the diameter.
- A long splice joins two ropes with almost no diameter increase, at some cost to strength, useful if the join needs to run through a block.
Tools You Need for Splicing
Splicing doesn’t take much equipment, but the right gear makes the difference between a clean splice and a fight with the rope:
- A fid (a tapered spike sized to your rope’s diameter) for opening the strands or core and guiding tucks. Our splicing kit for braids offers the tools in one set.
- A sharp knife or hot knife for cutting and sealing synthetic strand ends.
- Whipping twine or tape for seizing the throat of the splice.
- A tape measure and a permanent marker for laying out tuck points accurately.
- A smooth, secure work surface, splicing is much easier with the rope held steady.
The Steps of a Basic Eye Splice
The exact technique varies by rope construction, so treat this as the general shape of the process rather than a full tutorial, for a step-by-step matched to your specific rope, follow the manufacturer’s instructions or have it done by a professional splicer.
- Measure and mark the eye size you need, then mark a working length back from the rope’s end, this is roughly the amount that gets tucked or buried.
- Tape the working end to stop it unravelling, and separate the rope into its strands or expose the core, depending on construction.
- Tuck or bury the working end back into the standing part of the rope, following the rope’s own lay or braid pattern rather than working against it.
- Work the tucks through in sequence, pulling out slack after each one so the splice sits tight and even.
- Taper the last few tucks so the splice doesn’t leave a hard step where it meets the standing rope.
- Whip or lock-stitch the throat of the eye, then trim and seal any exposed ends.
Getting a Splice Right
A splice is only as good as its finish. A proper eye splice needs enough buried length, around 20 to 30 times the rope’s diameter (roughly one to one-and-a-half fid lengths), a properly whipped throat, and often a thimble and heat-shrink chafe protection to protect the eye from chafe.
That’s exactly why a lot of commercial and safety-critical splicing goes to a specialist rather than being done in-house.
Southern Ropes splices 3-strand, 12-strand and double braid rope to order, with leather eyes, thimble eyes, whipping, heat shrink and chafe protection all available. No matter how complex it is, we can splice it.
Contact us today for professional assistance with splicing.
Frequently Asked Questions
Is a splice always stronger than a knot?
Yes, a well-made splice typically retains 90% or more of the rope’s rated strength, while even a good knot can cut it by close to half.
Can any rope be spliced?
Most synthetic ropes can, but the technique depends on construction, 3-strand, 12-strand and double braid all splice differently.
How much strength does splicing actually save compared to knotting?
A properly made splice generally costs you no more than 10% of the rope’s rated strength. A knot can cost anywhere from roughly 40% to 60%, depending on the knot. On a load-bearing line, that gap is the difference between working within the rope’s safety margin and eating into it.
Can I splice a rope that’s already been used or shows some wear?
Only if the damage is limited to a section you can cut away and the rest of the rope, including the core, is sound and has passed inspection. If wear is spread across the rope, the core is compromised, or there’s internal powdering, splicing won’t fix it, that’s a retirement decision. See our Synthetic Rope Inspection Guide for how to tell the difference.
How long does a splice last?
As long as the rope itself, provided it’s inspected the same way as the rest of the rope and isn’t exposed to damage the splice can’t handle.
Can Southern Ropes splice my rope for me?
Yes, we splice 3-strand, 12-strand and double braid rope to order, with thimbles, whipping, heat shrink and chafe protection as needed. Contact us with your rope’s construction and application.
What’s the difference between a splice and a strop?
A strop is a short, pre-made loop or sling, usually spliced at both ends, used to rig or connect loads. We custom-make these too. Shop our strops and splice products.
