Marine chain comes with its own language.
G30, G43, G60, G70, ISO, DIN, BBB, WLL, breaking strength, and more: these terms can look technical, but each one tells you something important about the chain.
Some terms describe strength. Some describe dimensions. Some help determine whether the chain will fit your windlass. Others help you understand how the chain should be used.
The goal is not to memorize every term. The goal is to understand enough to compare chain correctly and avoid choosing the wrong product for your boat.
Grade vs. Standard
Grade and standard are related, but they are not the same thing.
Grade tells you about chain strength.
Standard tells you about chain dimensions and manufacturing specifications.
This difference matters because two chains can have the same diameter but different link dimensions. They may not fit the same windlass, even if the size looks similar.
For example, a 10 mm chain is not automatically the right chain for every 10 mm windlass. The chain still needs to match the windlass gypsy by standard, link length, width, and pitch.
When selecting chain, look at the complete specification rather than relying on grade or diameter alone.
What Is Chain Grade?
Chain grade describes the chain’s strength rating. Different grades are manufactured to meet different strength and performance requirements.
Grade is important, but it is only one part of choosing the right chain. Chain size, link dimensions, manufacturing standard, windlass compatibility, and how you use your boat all matter too.
Titan offers marine chain in several grades, including G30, G43, and G60, depending on the type and application.
Grade |
Common Name |
Typical Marine Use |
|---|---|---|
| G30 | Proof Coil | General-purpose and some anchor chain applications |
| G43 | High Test | Anchor and windlass chain where higher strength-to-weight is desired |
| G60 | Stainless Steel | Premium stainless windlass chain where appearance, stainless steel corrosion resistance, and correct windlass fit are priorities |
| G70 | High Strength | Specialized applications only where the chain, hardware, and use are rated for it |
G30 Chain
G30 chain is commonly used for general-purpose and some anchoring applications.
It may be appropriate where the chain matches the required size, standard, and load rating.
G30 is not automatically the right choice or the wrong choice. It depends on the full application.
G43 High Test Chain
G43 high test chain offers higher strength than G30 chain. It is often used for anchor and windlass applications where higher strength-to-weight is desired.
For many recreational anchoring setups, G43 chain is a practical choice when matched correctly to the windlass, anchor, rope, shackles, and load requirements.
Higher strength does not remove the need to confirm compatibility. The chain still needs to fit the full anchoring system.
G60 Stainless Steel Chain
G60 stainless steel chain is Titan’s premium stainless windlass chain. It is used where appearance, stainless steel corrosion resistance, and correct windlass fit are priorities.
Stainless steel is not corrosion-proof. In saltwater, stainless steel can still be affected by staining, pitting, or crevice corrosion, especially where salt deposits remain or oxygen is limited.
Choose stainless chain for the full application, not appearance alone.
G70 Chain
G70 is a higher-strength chain grade used in specialized applications. It should only be selected when the chain, hardware, and intended use are all rated for that application.
Higher grade does not automatically mean better for every boat. The correct grade is the one that matches the application.
What Are Chain Standards?
Chain standards define the dimensions and specifications the chain is manufactured to.
Common marine chain standards and types include:
- ISO 4565
- DIN 766
- BBB
- Grade L
- Proof coil
These terms are not interchangeable. A chain may be the right size but the wrong standard for your windlass.
A chain standard can affect:
- Link length
- Link width
- Link shape
- Pitch
- Windlass gypsy fit
- Compatibility with existing equipment
This is especially important when selecting windlass chain. The chain needs to physically match the windlass gypsy, so the correct diameter alone does not guarantee compatibility.
ISO 4565
ISO 4565 is a common windlass chain standard used in marine anchoring applications.
Titan offers ISO 4565 chain in multiple grades, including galvanized and stainless options.
If your windlass requires ISO 4565 chain, confirm the correct size, grade, and link dimensions before ordering.
DIN 766
DIN 766 is another short-link chain standard commonly used for windlass chain.
It is often found in metric anchoring systems.
If your windlass requires DIN 766 chain, confirm the correct size and fit before ordering.
BBB
BBB chain, also called BBB short-link chain, is a traditional chain pattern commonly used for anchors and windlasses.
BBB describes the chain’s construction and dimensions, not simply its strength grade. The chain must match the equipment it’s intended for, especially the windlass gypsy.
If your windlass requires BBB chain, choose the correct BBB size before ordering.
Proof Coil
Proof coil chain is commonly used for general-purpose and some anchoring applications.
It should only be used where its grade, standard, and dimensions match the application.
Proof coil is not automatically interchangeable with windlass chain. Confirm the full specification before ordering.
Working Load Limit and Breaking Strength
When comparing chain, you may see terms such as Working Load Limit, or WLL, and Breaking Strength.
Working Load Limit is the maximum recommended working load for the product under specified conditions.
Breaking Strength is the load at which the chain is expected to fail during a destructive test.
These numbers are not interchangeable.
Breaking strength is not a safe working load. It is a failure point from testing and should never be treated as the load the chain can safely carry in service.
Titan publishes working load limits and breaking strengths for its chain products. WLL must not be exceeded, and Titan chain is not intended for lifting or hoisting applications.
Common Mistake: Choosing Chain by Size Alone
Many boaters start with the chain size: 1/4″, 5/16″, 3/8″, 8 mm, 10 mm, and so on. Size is important, but it is not enough on its own.
Before choosing anchor chain, confirm:
- Chain size
- Chain grade
- Chain standard
- Link dimensions
- Windlass compatibility
- Shackle or connecting hardware fit
- The way you use your boat
This is especially important if your boat has a windlass. The wrong chain may skip, jam, or fail to run properly through the gypsy.
Simple Way to Remember It
- Grade helps answer: How strong is the chain?
- Standard helps answer: Will this chain fit the equipment it needs to work with?
- WLL helps answer: What load is the chain rated to carry in service?
- Breaking strength helps answer: At what load did the chain fail in destructive testing?
- Diameter helps answer: What size is the chain?
- Link dimensions help answer: Will it fit the windlass and connecting hardware?
The right chain is not simply the highest grade or largest diameter. It is the chain that matches the application as a complete specification.
Frequently Asked Questions
What is the difference between G30 and G43 chain?
G43 chain has higher strength characteristics than G30 chain, allowing it to provide a higher strength-to-weight ratio. The appropriate grade depends on your intended application, load requirements, and equipment compatibility.
For many anchor and windlass applications, G43 may be chosen when higher strength is needed without simply moving to a larger or heavier chain.
What is the difference between chain grade and chain standard?
Chain grade describes the chain’s strength rating. A standard such as ISO or DIN defines the dimensions and specifications the chain is manufactured to.
Both can be important when selecting chain for a boat, especially if the chain needs to run through a windlass.
What does BBB mean on marine chain?
BBB is not simply another way of stating chain grade. If your windlass requires BBB chain, the chain must match the required BBB dimensions.
What is DIN 766 chain?
DIN 766 is a German standard that specifies dimensions and requirements for short-link chain. It is commonly encountered when selecting chain for marine and windlass applications.
If your windlass requires DIN 766 chain, confirm the correct size and fit before ordering.
Does chain grade determine windlass compatibility?
Windlass compatibility also depends on the chain’s dimensions and whether those dimensions match the windlass gypsy.
A chain can be the right grade and still be wrong for your windlass if the dimensions do not match.
Can I choose anchor chain by diameter alone?
Can I choose anchor chain by diameter alone?
No. Diameter is only one part of the chain specification.
Two chains with the same diameter can have different link lengths, widths, grades, and standards. If the chain will run through a windlass, always confirm the full chain specification required by the windlass manufacturer.
Is higher-grade chain always better?
Not always. Higher-grade chain can offer higher strength, but the best chain is the one that matches the application.
Your anchor, windlass, shackles, rope, and chain all need to work together as a system.
Is stainless steel chain corrosion-proof?
No. Stainless steel has corrosion-resistance advantages in many marine applications, but it is not corrosion-proof.
In saltwater, stainless steel can still be affected by staining, pitting, or crevice corrosion, especially in crevices, stagnant water, or areas where salt deposits remain.
Can Titan chain be used for lifting?
Use Titan chain only for the application it is designed and rated for.
Final Check Before You Buy
Use this guide as a starting point. Always confirm the chain size, grade, standard, windlass compatibility, and hardware ratings for your specific vessel before purchase.
Use this guide as a starting point. Always confirm the chain size, grade, windlass compatibility, and hardware ratings for your specific vessel before purchase. Anchoring is safety-critical equipment.