Are all anchor chain’s the same?

The short answer is a very big ‘NO’…….. There are in fact a variety of types and grades of anchor chain that cruising sailors should know about. What follows is a brief explanation on how to understand the various grades, sizes and qualities of anchor chain that leisure sailors commonly use.

Types of Anchor Chain Explained

Chain Type Description
Non Calibrated Chain
This is chain that is generally manufactured on older type machinery and is only suitable for boats that do not have a windlass. Non Calibrated Chain is generally produced using Grade 30 materials.
Calibrated Chain
Is manufactured in a way which insures that every link is of the same diameter, modern chain making machines automatically calibrate the chain immediately after the link welding process is complete, the calibration is generally achieved by stretching a short section of chain (+-/30cm) in order to maintain a constant and precise link profile, this process is continued throughout the whole length of chain.

Grades of Anchor Chain

Up until the recent past there were only two grades of calibrated and non calibrated marine anchor chain in general use, these were Grades 30 and 40, they have now been joined by Grade 43 and Grade 7 (70).

Grades of Anchor Chain Description
Grade 30 Calibrated Anchor Chain
Grade 30 chain is manufactured using low-carbon steel, consequently its strength factor is lower than higher grades, generally it is not calibrated and rarely link stamped. We no longer stock Grade 30 Calibrated Chain
Grade 40 Calibrated Anchor Chain
Grade 40 is currently the most popular grade, it is manufactured using a high carbon manganese alloy material. This higher tensile calibrated windlass chain is widely used because of its strength factor which is higher than the lower grade chain. Good quality grade 40 calibrated chain is generally link stamped at intervals of between one and two meters. Another plus for this grade of calibrated chain is that it tends to resist tangling in the chain locker. We have high quality Grade 40 Calibrated Chain available ex-stock from two manufactures.
Grade 43 Calibrated Anchor Chain
A relative newcomer on the yachting scene, this grade in a long link format has previously been used as lashing chain on heavy vehicles carrying such things as logs. It has a higher strength factor than the previous grades. We have recently introduced Grade 43 to our Calibrated chain range. Available as part of our high quality ‘Titan’ High Quality chain range.
Grade 70 Calibrated Anchor Chain
High strength Calibrated Anchor Chain is designed to help eliminate the additional wear, stresses and strains associated with long distance cruising. It is also a practical option for reducing the weight in the chain locker by stepping down the chain size whilst retaining the strength factor, alternatively, it gives the option to increase the chain length whilst retaining the same weight in the locker. For example; Grade 70 calibrated chain is manufactured to such a high specification that it is possible to substitute 10mm Grade 40 anchor chain with a far longer length of 8mm Grade 70 calibrated chain without losing any strength e.g. 100mtrs of 10mm chain would weigh 220kgs, 100mtrs of 8mm Grade 70 calibrated chain would weigh 140kgs and be stronger! Available as part of our best quality MF range of Calibrated Chains
AISI 316 Stainless Steel Calibrated Anchor Chain
Grade 316 Stainless Steel Calibrated Chain is for some yachtsman the ultimate choice for marine use, unfortunately it comes at a higher cost than steel chain but for longevity it is unsurpassed. The strength factor is marginally less than normal galvanised chain, it has excellent flaking characteristics in the chain locker and always looks expensive! Available as part of our high quality ‘Titan’ chain range.

If your requirement Calibrated Chain that has been certified to the equivalent of Lloyds Register, Bureau Veritas or American Bureau of Shipping then we can offer:

What is Rina Certification?

RINA is the Italian Classification Society and as such it is equivalent to Lloyds Register in the UK - Bureau Veritas in France - ABS in the USA

Classification societies set technical rules based on experience and research, they confirm that designs, calculations and manufacturing procedures meet these rules. They ensure by inspection that the product meets their specification.

If your chain has Rina Certification it is the very best available. Only available through EYE Marine Ltd or BGD

We are not aware of any other supplier offering chain of this quality in the UK, this indicates the general level of excellence offered by EYE Marine/BGD

Composition of steels for chain manufacture

The strength of finished chain is determined by the content and treatment of the steel used for its manufacture.

Grade Description
Grade 30
is the lowest strength marine chain, it is produced from low carbon steel such as DIN 10301.
Grade 40
the carbon and manganese contents are increased, giving about a 25% increase in strength, but without heat treatment. This steel is typically DIN 1.1133 (EU). Grades 30 and 40 may be galvanized without concerns over strength reduction.
Grade 70
this chain is manufactured from the same steel as Grade 40 but it is heat treated to increase strength by a further 20%. Galvanising this type of chain requires specialist treatment.

Calibrated Chain Test Loads to Breaking Point

The Test Loads shown are Anchor Chains currently stocked by EYE/BGD.

(Break point is where the chain starts to deform this is sometimes called Yield Point)

Please be advised that marine chains are not suitable for overhead lifting

Chain Size 6x18.5mm 7xx22mm 8x24mm 10x28mm 10x30mm 12x36mm 13x36mm 14x42mm 16x45mm
Break Load Kgs
Break Load Kgs
Break Load Kgs
Break Load Kgs
Break Load Kgs
Break Load Kgs
Break Load Kgs
Break Load Kgs
Break Load Kgs
Titan G40
MF G40
Titan G43
MF Aqua G70
Titan AISI 316

Inspecting your Calibrated Chain

Inspect your chain carefully and regularly. Rusting calibrated chain can produce variations within its dimensions, consequently this may result in chain jumping on the gypsy and could eventually result in the chain jamming the windlass, additionally failing to use the correct calibrated chain for a specific windlass can also lead to potentially dangerous jamming where the chain cannot be either raised or lowered.

High-quality calibrated chain from reputable manufacturers is embossed with a stamp indicating the grade, without one, you’ll be guessing about the chain’s strength, best practice is to ask for a Certificate of Conformity (Test Certificate) when you purchase your chain.

Hot Dip Galvanising (HDG)

Hot Dip Galvanizing is a unique process. When clean steel is immersed into molten zinc, a series of zinc-iron alloy layers are formed by a metallurgical reaction between the iron and zinc, providing a robust coating which is an integral part of the steel.

Calibrated anchor chain has a tough life, particularly on liveaboard cruising boats that possibly spend half the year or more swinging at anchor. Although it is becoming more common to see stainless steel chain on yachts it is true to say that the vast majority of chain used by yachtsmen has been Hot Dip Galvanised to provide corrosion protection. The galvanising provides a zinc coating which gradually corrodes while protecting the steel chain. Zinc is also lost by wear, both against the seabed and during the launch and recovery process. Eventually the steel is no longer protected, as shown by rust on the chain, this eventually result in unsightly stains on the decks. Zinc is also lost by wear, both against the seabed and during the launch and recovery process. Eventually the steel is no longer protected. The thickness of galvanising is measured in Microns the marine industry standard is 100 Microns, all galvanised chain sold by EYE Marine/BGD equals or exceeds this requirement. MF Calibrated Chain offers additional galvanised chain qualities.

Solid Zinc Galvanising

MF have developed an enhanced Solid Zinc Galvanising treatment which works in conjunction with the standard hot dip galvanising process. This process is used throughout their calibrated chain range.

Solid Zinc Galvanising is an MF duplex treatment where both aspects of the process are complementary hot dip molten zinc galvanisation. The improved coverage, micron depth and adhesion properties extend the effective working life of the galvanising by up to 25%. Solid Zinc galvanising has a bright smooth appearance.

How to measure Calibrated Chain

  1. Using a Vernier Calliper measure point A (but not at the weld point or within the inside of the U part of the chain).
  2. If you suspect that the chain has become elongated through wear, measure the overall length of the link and then deduct the measurement at point A x 2 which will give the inside link measurement.
  3. If you are certain that the measurement at point A is 6 – 7 – 8 – 12 – 13 or 14mm then there is no need to take more measurements as the other dimensions are set standards.
  4. If you are not sure then measure point B (This is the inside link length or pitch), we can use this measurement to confirm A.
  5. If point A is 10mm then it is essential that you measure point B, this is because 10mm chain is manufactured with two different inside link lengths which will vary depending on the windless manufacturer.
  6. If you are measuring 12 or 13mm chain which have the same inside link length and want to confirm the A measurement then also measure point C – if its 40mm then you have 12mm chain, if it is 44mm then it is 13mm chain.
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