Eye Splice — Double Braid

How Double Braid Is Different

Three-strand splicing uses over-under tucks to interweave strands. Double braid splicing is fundamentally different: it uses a telescoping 'bury' technique where the core is pulled out of the cover and the cover is buried back into the core — the two components lock around each other under load.

The result is called a bury splice or cover-over-core splice. It is the strongest way to terminate double braid rope: a correctly made bury splice retains 85–95% of the rope's breaking strength. The load is shared between the core and cover through their interlocked buried sections.

The technique requires a set of fids — typically a hollow tubular fid and a pusher/pull wire tool. Most rope manufacturers specify fid length in multiples of the rope diameter, and fid sets are sold for specific rope diameter ranges.

The learning curve is steeper than three-strand, but the technique becomes intuitive once you understand the geometry. Every step exists for a reason — understand the 'why' and you can troubleshoot your own work.

Tools and Marking

A double braid bury splice requires specific fid tools — the technique cannot be done adequately without them. For ropes under 10mm, a small hollow fid works. For 10–16mm rope, a medium fid. Fid kits are available from West Marine, Sailing Pro Shop, and direct from rope manufacturers.

Required tools:

- Hollow tubular fid — for threading the cover through the core

- Pull-through wire or splicing needle — for drawing the cover/core through long buried sections

- Sharp knife — for trimming and tapering

- Permanent marker — for marking reference points

- Masking tape — for marking and bundling

Marking sequence (standard Samson method):

1. Measure one fid length from the end — mark the cover here as Point A (throat of the eye).

2. Open the cover at point A to extract the core. Pull out enough core to work with.

3. Mark the core at the point where it exits the cover as Point B. Mark one short fid length past B on the core as Point C.

4. Mark the cover one short fid length past point A as Point D.

Getting the marks right before any splicing begins is the difference between a correctly positioned splice and one that unloads unevenly.

The Bury Sequence — Step by Step

With marks in place, the splice itself follows a logical sequence:

Step 1 — Bury the core into the cover:

Insert the fid at Point D on the cover and push it through the cover braid, exiting further down the cover body. Thread the core tail into the fid and pull it through, so the core end exits out through the cover body. Adjust until Point C on the core aligns with Point D on the cover.

Step 2 — Bury the cover into the core:

Insert the pull wire into the core at Point B and push it through the hollow core body, past the buried core section. Attach the cover tail to the wire and draw it through, so the cover is buried inside the core body. Adjust until Point A on the cover is at the throat.

Step 3 — Milk and set:

With both components buried, 'milk' the splice — grip the rope on each side of the splice and push firmly toward the center, working all slack out of the buried sections. The splice will compact as the cover and core lock around each other.

Step 4 — Taper and trim:

Trim the exposed core and cover tails at the exit points. Taper by removing fibers from the tails before making the final tuck or bury, so the splice doesn't create a hard lump at the exit point.

Step 5 — Crosslock (optional but recommended):

Some riggers add a locking stitch through the rope body at the splice throat using a sailmaker's needle and whipping thread — passed through the core and cover together, several times in an X pattern. This prevents the splice 'unlocking' if the load direction reverses.

Finishing and Common Mistakes

Finishing: After milking and tapering, heat-seal or whip the tail ends. Apply a tight whipping at the throat (Point A) if a crosslock stitch wasn't used. This protects the splice entry point from abrasion.

Testing: Pull progressively. The splice should be completely smooth under load — no lumps moving, no cover bunching. A correctly made bury splice feels like one piece of rope, not a join.

Common mistakes:

- Burying the wrong direction: The cover must be buried in the direction that allows it to draw tighter under load, not looser. Check the manufacturer's diagram for your rope.

- Insufficient milking: Leaving slack in the buried sections means the splice relies on the tail length alone, which may not be enough. Milk thoroughly.

- Cutting the bury too short: If you cut the tails before milking fully, you may realize the buried sections are shorter than specified. There is no fixing this — splice again.

- Wrong fid size: Using a fid too large for the rope diameter distorts the braid structure and weakens the bury zone. Match fid to rope diameter.