Arcus archives

"It's the Same Wire." Is It?

Monday 13th July 2026

If you’ve been buying hamma® wire rope, chances are someone has approached you recently with a cheaper alternative. Same grade, same breaking load, Korean-made. The pitch is simple: it’s identical wire at a better price. It’s a fair question, so here’s a straight answer.

hamma® is the stainless steel wire rope brand supplied by Arcus Wire Group and manufactured in South Korea by KOS.

On paper, the case looks solid

Both carry an AISI 316 certification. Chemical composition is virtually identical. Molybdenum content, the element most relevant to marine corrosion resistance, sits around 2.0–2.1% across Korean-manufactured wire rope regardless of brand. MBL tests to spec. The cert looks the same.

Why this matters more on a yacht than almost anywhere else

Rigging wire on a yacht doesn’t get a break. It’s in constant salt spray or full immersion, sits in tight swages and terminal fittings that trap moisture, and rarely gets removed and properly inspected until something already looks wrong. Those are the exact conditions that initiate crevice corrosion: low oxygen, high chloride, hard to clean.

It’s also safety-critical. Standing rigging failure isn’t a cosmetic repair, it’s a dismasting, at sea, often a long way from a rigger who can fix it. Running rigging failure under load is its own risk to the crew. This isn’t a component where “close enough” is acceptable.

It’s not just structural, either. Surveyors and insurers assess rigging condition at haul-out, and pitting, staining or a rough surface tells a different story to an underwriter than rope that still looks new after years in service. On superyachts especially, rigging is often on display rather than hidden below decks, so finish is also part of how the vessel presents.

Grade gets a rope through certification. Finish and cleanliness are what decide whether it still looks and performs like new five years into a marine environment that never lets up.

Why finish is rated alongside grade, not beneath it

Corrosion resistance isn’t just chemistry. The Australian Stainless Steel Development Association (ASSDA) treats surface finish as a separate factor to grade, not a cosmetic afterthought, and rates them side by side. Their reasoning:

Smoothness stops corrosion starting. Surface roughness helps initiate corrosion, so a cleaner, smoother surface is one of the main ways to minimise it.
Rough finishes trap what causes corrosion. Dirt, chlorides and moisture sit in surface texture and initiate pitting and crevice attack, regardless of how good the grade’s chemistry is.
Finish drives clean-ability, not just appearance. Surface quality affects both corrosion sensitivity and how easily the material can be cleaned.
In harsh environments, finish can decide performance. ASSDA lists surface finish alongside grade, design and maintenance as a factor with a substantial impact on how stainless performs in demanding, borderline conditions.
It’s one of four levers in preventing crevice corrosion, alongside grade selection, design and maintenance, named as an equal, separate factor to grade.

The practical read for wire rope and rigging: a correctly graded 316 rope can still underperform if the finish is rough or poorly prepped, because the failure starts at the surface, not the bulk chemistry. Grade was never the whole spec, and ASSDA’s own standard says as much.

What the cert doesn't measure

Stainless steel wire starts as rod stock. It gets drawn down through a series of dies to reach its final diameter, a process that requires lubricants like oils and soaps. Without them, the wire seizes. They are not optional.

What is optional is what happens to the rope after it’s stranded.

If it’s coiled and boxed without a proper cleaning step, residual contamination gets locked into the gaps between strands. In a marine environment, that contamination sits exactly where salt water pools and oxygen is limited. It disrupts the passive oxide layer that gives 316 its corrosion resistance, and starts working against the rope long before there’s any outward sign of it.

A cert confirming AISI 316 tells you the alloy is right. It tells you nothing about what’s on the surface, or inside the rope, when it left the factory.

What KOS does differently

KOS runs a final Ultrasonic Cleaning process on the finished rope after stranding, as a production standard, not an occasional check. High-frequency sound waves generate microscopic vapour bubbles in the cleaning bath. Those bubbles collapse against the wire surface, and each collapse produces a tiny, high-pressure microjet, physically dislodging oil film and particulate from the gaps between individual strands and wires. That geometry is the point: a rinse, brush or chemical soak only acts on exposed surfaces. It can’t reach into a stranded rope’s internal crevices. Cavitation reaches them.

That’s also why this has to happen after stranding, not before. Cleaning individual wires before they’re stranded does nothing for the contamination that gets trapped once the strands are laid up. KOS’s process also runs several QA/QC checkpoints through production specifically to verify cleanliness, so the ultrasonic stage isn’t the only line of defence, it’s the final one behind a process built to check for this at multiple points.

The result is a rope that’s clean at the core when it enters service. The passive layer is intact. There’s no contamination head start working against you from day one. Not every Korean manufacturer maintains this standard. The process takes time, capital and discipline. It doesn’t show up on a cert.

This differentiator happens earlier, at the drawing stage, before the wire is ever stranded or cleaned.

Wire is drawn to size by pulling it through a series of progressively smaller dies under high friction and pressure. If the lubricant film between the wire and the die is inconsistent or breaks down under that pressure, the die doesn’t smoothly compress the surface, it tears it, at a microscopic level invisible to the naked eye. KOS’s proprietary Precision Wet-Drawing Lustre Technology uses a controlled lubricant film during drawing to minimise that surface micro-tearing at the source, producing the consistently mirror-bright, high-lustre finish that distinguishes KOS stainless wire rope.

That matters for two reasons, not one. A micro-tear behaves like a micro-crevice, and surface-level defects like this are the kind of thing that gives corrosion somewhere to start, so a smoother wire has a head start on corrosion resistance before it’s ever stranded or cleaned. Surface defects also act as stress-concentration points in a wire rope that flexes constantly under load, over sheaves, swages and fittings, so a smoother, more uniform wire surface has fewer of those points, an argument for fatigue life, not just appearance.

Composition Comparison - AISI 316, 1x19

	KOS	Other Korean brands
Molybdenum	2.062%	~2.030%
Nickel	10.772%	~10.741%

The alloy is not the differentiator. The 0.03% Mo difference is manufacturing noise. Both are genuine 316. What separates them, and what ASSDA says matters just as much, is what happens during and after drawing: how the wire is finished, and how the finished rope is cleaned.

We saw it under a microscope

During a visit to the KOS facility in South Korea, we examined wire rope cross-sections under their microscopic analysis equipment, the same lab they use for production quality control. Samples from KOS and samples from other Korean suppliers, side by side.

The difference wasn’t subtle. Under magnification, the KOS wire showed a smooth, uniform surface lustre with consistent strand geometry. The alternative samples showed surface irregularities and roughness, exactly the kind of surface condition that initiates corrosion, completely invisible to the naked eye and never captured on any certificate.

That’s the drawing-stage control showing up in the metal. It’s a process refinement, developed over years of manufacturing, not a chemistry change, and it shows up in the wire long before it’s ever tested to failure.

Next time you're offered cheaper Korean wire at the same spec, ask two questions.

What is the post-stranding cleaning process?
What produces the surface finish?

A detailed answer tells you something. A vague one tells you more.

Chemistry and breaking load only get you to the starting line. What you’re paying for with hamma® is everything that happens in the factory after those boxes are ticked, and the difference is visible if you know where to look. For yacht rigging, where the marine environment never lets up, that finish and cleanliness are what make hamma® by KOS the wire worth specifying.

Frequently asked questions

1. Is hamma® the same as other Korean 316 wire rope?

No. hamma® and other Korean brands both meet AISI 316, test to the same breaking load, and have almost identical chemistry. What differs is how the wire is finished during drawing and how the finished rope is cleaned after stranding, and that is where hamma® by KOS is made differently.

2. What does KOS do differently?

Two things. KOS runs a post-stranding ultrasonic cleaning process as a production standard, using cavitation to lift drawing lubricant and particulate out of the internal crevices of a stranded rope, where a rinse or chemical soak cannot reach. It also uses Precision Wet-Drawing Lustre Technology to control the lubricant film during drawing, reducing surface micro-tearing and producing a smoother, mirror-bright finish.

3. Why does surface finish matter as much as grade?

The Australian Stainless Steel Development Association (ASSDA) rates surface finish alongside grade, design and maintenance as a factor in preventing crevice corrosion. A rough surface traps chlorides and moisture and gives corrosion somewhere to start, so a correctly graded 316 rope can still underperform if the finish is poor.

4. Is hamma® by KOS suitable for yacht standing rigging?

Yes. It is made for the conditions yacht rigging faces: constant salt exposure, moisture trapped in swages and fittings, and long intervals between full inspections. A clean core and a smooth, uniform finish help the passive oxide layer stay intact, so the rigging keeps looking and performing like new for longer.

hamma®. Performance by design.

Arcus Wire Group supplies hamma® wire rope across Australia and New Zealand.

Arcus Wire Group is a recognised leader in wire rope, chain, hardware, and stainless steel mesh for over 60 years. We bring a wealth of experience, knowledge, and expertise to help customers with projects of any size or complexity.

For technical queries or certification documentation, please contact our business development team Anton Hendriks, Kris Corbett, Desmond Pronk, Aleisha Salmon, and Matthew Doherty on 1800 ARCUSW (1800 272 879) or email [email protected].