Fishing and aquaculture twine is one of the few cordage categories where the buyer and the supplier both speak the same technical language — denier and ply — and where matching a replacement to an existing net is part of the job. A wrong twine is more than an inconvenience on a working net; a heavier twine changes the mesh, a lighter twine changes the breaking load, and a different material can change the handling of the net itself.
The denier × ply system
Denier is the weight in grams of 9,000 meters of a single yarn. A 210 denier (210D) base yarn is a common reference weight in fishing and packaging twine. The ply number says how many of those yarns are twisted together to form the twine.
- 210D/9 — fine twine, light nets, hand knitting
- 210D/12 — general-purpose mending twine for small and medium nets
- 210D/15, 210D/18 — heavier twine for larger meshes and heavier gear
- 210D/24, 210D/36 — heavy twine for trawl nets, headline ropes and structural netting
The bigger the ply, the heavier, stronger and stiffer the twine — and the more it changes the geometry of a mesh it is knotted into.
Material and yarn form
- PE monofilament. The global standard for net repair and aquaculture. Stiff, abrasion-tolerant, slightly waxy to the touch. Holds knots reliably. Floats.
- PE multifilament. Softer and more flexible. Used where hand feel matters (some hand knitting, decorative netting).
- PP monofilament. Stiffer and cheaper than PE. Used where price matters more than hand feel.
- PP split film. Flat, low-cost twine for bale twine and agricultural tying, not typically a fishing product.
Common fishing uses by twine size
| Use | Typical twine |
|---|---|
| Gillnet mending | 210D/9 to 210D/12 |
| Small aquaculture cage netting | 210D/12 to 210D/15 |
| Large aquaculture cages | 210D/18 to 210D/24 |
| Trawl nets and headline ropes | 210D/24 and heavier, often with specific HS code |
| Longline and pot rigging | 210D/15 to 210D/24 |
Specifying a replacement
The fastest way to match a replacement to an existing net:
- Cut a short sample of the existing twine and measure its diameter or runlength (m/kg).
- Count the ply if it is a twisted construction.
- Identify the material by feel (PE waxy, PP hard, natural fiber hairy).
- Note the color and any UV-stabilization (white PE that has yellowed has been in the sun a long time).
- Send the sample and the field data to the supplier for direct match.
For a new program, the same denier × ply system is used in the RFQ. Add: quantity, packaging format (ball, spool, reel), color and any specific knot strength or UV requirement.