How to Choose a Lead Line for Trawling
Getting the lead line right is one of the most overlooked steps in trawl net setup — and one of the most important. Choose too light a line, and your net won't hold bottom contact; choose the wrong construction, and you'll be replacing gear every season. Here's what actually determines performance.
What Is a Lead Line?
A lead line (also called lead core rope or lead sinker rope — the terms are used interchangeably in the industry) is a rope built around a dense lead core, encased in a braided or twisted outer jacket. Unlike loose lead weights clipped along a footrope, a lead line distributes weight evenly across its entire length, giving the net a smoother, more predictable sink and better contact with the seabed or water column.
Key Factors When Choosing a Lead Line
1. Lead loading (weight per metre)
This is the single biggest factor in sink rate. Heavier loading means faster, more aggressive sinking — useful for deep-water trawling or strong currents. Lighter loading suits shallower grounds or gear where you want the net to settle more gently. There's no universal "correct" weight; it's matched to your target depth, current conditions, and net design.
2. Rope diameter
Diameter affects both handling and durability. Thicker lines resist abrasion better and last longer under constant seabed contact, but add bulk and weight to your gear. Thinner lines are easier to handle and store but wear faster in rocky or coarse-bottom conditions.
3. Outer jacket construction
Braided jackets tend to resist kinking and hold their shape better over repeated hauling. Twisted constructions can offer a different balance of flexibility and cost. The jacket is what takes the abrasion — the lead core inside is protected as long as the outer sheath holds up.
4. Abrasion and UV resistance
Trawl lines spend most of their working life dragging against the seabed and are stored on deck under constant sun exposure. A lead line built for saltwater use should resist corrosion, abrasion, and UV degradation — otherwise you'll see premature fraying, weight loss, or core exposure well before the rope should be due for replacement.
5. Saltwater vs freshwater use
Saltwater trawling places greater stress on the outer jacket due to corrosion and salt crystallisation. Make sure the lead line you choose is rated for continuous saltwater immersion if that's your operating environment — freshwater-rated lines may not hold up as well.
6. Consistency along the length
A well-made lead line keeps its weight evenly distributed with no bunching or shifting over time. This matters more than people expect — uneven weight distribution along a footrope leads to uneven bottom contact, which directly affects catch efficiency.
Matching the Lead Line to Your Net
There's no single spec that works across all trawl setups. A bottom-set trawl working rocky or coarse ground benefits from a heavier-diameter line with strong abrasion resistance, while a mid-water or lighter trawl can often run a thinner, lower-loading line without sacrificing performance. Aquaculture cage moorings have their own requirements again, generally prioritising long-term saltwater durability over sink speed.
The safest approach is to work from your actual depth, current, and seabed conditions rather than defaulting to "whatever was used last time" — gear that's underspecified for the conditions wears out fast, and gear that's overspecified adds unnecessary cost and handling weight.
Get the Right Spec for Your Operation
Shreeline Industries manufactures both [lead core rope] and [lead sinker rope] in a range of diameters and lead loading options, built to withstand continuous saltwater exposure, abrasion, and UV degradation for commercial fishing and aquaculture applications. If you're unsure which specification suits your trawl gear, [get in touch with our team] for a spec sheet or custom quote — we'll help you match the lead line to your exact operating conditions.