Proof Tested Anchor Chains Explained: What Proof Testing Really Protects You From

When shopping for an anchor chain, the phrase proof tested shows up everywhere. It sounds reassuring—but many boat owners don’t actually know what proof testing means, or what it truly protects them from.

At ShakeSure, we believe proof testing is one of the most important quality checks in anchor chain manufacturing—but only when it’s properly understood. This guide explains what proof testing really does, what it doesn’t do, and why it matters when choosing a safe, reliable anchor chain for your boat.

What Proof Testing Actually Means

Proof testing is a controlled load test applied to an anchor chain during manufacturing. The chain is subjected to a force higher than its normal working load, but still well below its breaking strength.

The goal is simple: to confirm that every link can safely handle real-world loads without deforming, cracking, or failing.

This test is non-destructive. After proof testing, the chain remains fully usable and ready for service. Unlike breaking tests, which destroy samples, proof testing verifies quality without damaging the chain.

In short, proof testing is not about pushing a chain to failure—it’s about confirming that it performs exactly as designed.

What Proof Testing Really Protects You From

This is where proof testing delivers its real value.

Proof testing is designed to catch hidden manufacturing defects that aren’t visible during visual inspection. These include:

• Incomplete or weak welds between links

• Internal material flaws within the steel

• Inconsistent link geometry that may deform under load

• Early-stage weaknesses that only appear when tension is applied

These defects can exist even in brand-new chains. Without proof testing, they may only reveal themselves when your boat is already anchored and under load—when failure is most dangerous.

By applying a controlled proof load, these issues are identified before the chain ever reaches the water.

What Proof Testing Does Not Protect You From

This is an important point—and one many sellers avoid mentioning.

Proof testing does not protect an anchor chain from:

• Long-term corrosion from saltwater exposure

• Abrasion damage caused by rocky or rough seabeds

• Galvanic corrosion from mixed-metal connections

• Incorrect chain size, grade, or calibration selection

Proof testing confirms initial structural integrity, not lifetime durability. A proof-tested chain can still corrode or wear out if the zinc coating is thin, if it’s used in harsh environments, or if it’s not properly matched to the boat and anchoring conditions.

That’s why proof testing should always be considered one layer of safety, not the entire solution.

Proof Testing vs Breaking Strength (MBL) Explained Simply

Another common source of confusion is the difference between proof testing and Minimum Breaking Load (MBL).

• Proof testing applies a controlled load to confirm quality and consistency.

• Breaking tests push sample chains to failure to determine maximum strength.

The breaking strength value you see in specification tables is determined through destructive testing of samples, not every chain length. Proof testing, on the other hand, is used to ensure that production chains meet those design expectations in real use.

Both are important—but they serve different purposes.

How Proof Testing Fits Into ShakeSure’s Quality Standard

At ShakeSure, proof testing is not optional. Every anchor chain we supply is proof tested as part of the manufacturing process, ensuring consistent performance and safety.

In addition:

• Chains are checked for dimensional accuracy and calibration

• Galvanized chains are assessed alongside zinc coating quality

• Manufacturer test certificates are available upon request, confirming compliance with applicable standards

We don’t rely on labels alone. Proof testing is one part of a broader quality system designed to reduce risk and give boat owners confidence in every length of chain we supply.

Conclusion

Proof testing plays a critical role in anchor chain safety—but only when it’s properly understood.

It protects you from hidden manufacturing defects, confirms structural integrity, and ensures that a chain performs as designed from day one. What it doesn’t do is replace good material selection, corrosion protection, or correct sizing.

At ShakeSure, we combine proof testing with careful chain selection, proper standards compliance, and transparent documentation—so you’re not just buying an anchor chain, you’re choosing one that’s been verified for real-world use.

ShakeSure — because confidence at anchor starts with knowing what your chain has been tested for.