Mooring Chain Explained

Is all mooring chain the same?

The short answer is a very big ‘NO’…….. There are now a variety of types and grades of mooring chain that you should know about if you are laying or maintaining a mooring. What follows is a brief explanation on how to understand the various grades, sizes and qualities of mooring chain that are available for use.

In the recent past there was only one grade of open link mooring chain in sizes under 26mm that were suitable and readily available for mooring contractors and others to use, this was Grade 30, which is manufactured using low-carbon steel, consequently its strength factor is low when compared to the higher grade mooring chains that are now available from EYE Marine Ltd and Boat Gear Direct.

EYE Marine Ltd and Boat Gear Direct have discontinued supplying most sizes of Grade 30 chain in favour of the better quality higher grades, there are some exceptions but these are used for less demanding applications.

Grade 40 is currently the most popular grade mooring chain, it is manufactured using a high carbon-manganese alloy material. This higher tensile chain is now widely used be- cause of its strength factor which is higher than the Grade 30 chain. We have large stocks in sizes from 10 to 22mm. When larger sizes are required we have these available in Grade U2.

We offer Grade 40 and U2 mooring chain from two sources;

MF Catenificio Frigerio SRL based in Lombardy Italy. We stock sizes 10 to 22mm in Mid-link format. Other sizes are available to special order.

Over 95% of the worlds commercial and military shipping fleets (including the Royal Navy) use anchor chain that has been manufactured in China, our supplier produces chain that been produced on machines that incorporate the latest chain making technology. They have a number of Classification Society accreditations, all chain is manufactured to meet their requirements.

What is the difference between Short-link, Mid-link and Long-link chain?

Short-link chain has overall link dimensions that do not exceed 5 times the material diameter (A) in over- all length (D) and 3.5 times the material diameter in overall width (C). For example a link 10mm Short-link chain should have outside link dimensions no larger than 50 x 35mm thus (internal dimensions would be 30mm internal length x 15mm internal width).

Short-link chain is the strongest of the three configurations, unfortunately, because the shackle size that can be used with this chain is relatively small it is not the best choice for use in mooring assemblies, un- less welded into a bespoke mooring assembly in our marine fabrication unit.

Mid-link chain has overall link dimensions that do not exceed 6 times the material diameter (A) in overall length (D) and 3.6 times the material diameter in overall width (C). For example a link 10mm Mid-link chain should have outside link dimensions no larger than 60 x 36mm thus (internal dimensions would be 40mm internal length x 16mm internal width).

Mid-link chain is a good compromise for mooring use, offering most of the benefits of short link together with the ability to allow the use of shackles with the same body size as the link material.

Long-link chain has overall link dimensions that do not exceed 8 times the material diameter (A) in overall length (D) and 4 times the material diameter in overall width (C). For example a link 10mm Mid-link chain should have outside link dimensions no larger than 80 x 40mm thus (internal dimensions would be 60mm internal length x 20mm internal width).

The advantages of using Long-link mooring chain is its ability to accept the use of larger shackles and swiv- els, additionally it is lighter in weight for its size, this could be an important factor when choosing which size mooring buoy to use, lastly its generally the most cost effective option.

Size A mm	Pitch B mm	Width C mm	Weight Kg/mtr	Min Break Load Kg	Metres per Ton	Grade	Ex-stock Self	Ex-stock Italian	Ex-stock HDG
8	52	32	1.15	2300	870	40	Yes	–	Yes
10	35	35	2.13	4500	469	30	Yes	–	Yes
10	53	39	1.84	3600	543	30	–	–	Yes
10	40	40	2.1	4300	543	30/40	–	–	Yes
12	61	47	2.58	5500	388	40	Yes	–	Yes
12	48	48	2.98	6500	336	40	Yes	Yes	Yes
12	36	40	3.3	8000	303	40	–	Yes	Yes
13	81	52	2.95	7500	339	40	Yes	–	Yes
14	56	51	4.2	10000	238	40	Yes	–	Yes
16	64	56	5.0	14500	207	40	Yes	–	Yes
16	80	56	4.6	14000	217	40	Yes	Yes	Yes
16	100	66	4.5	13000	222	40	Yes	Yes	Yes
18	63	62	6.7	16000	149	40	Yes	–	Yes
18	90	66	6.2	14500	161	30	Yes	–	–
19	97	68	6.5	20000	154	40	Yes	–	Yes
19	75	68	7.0	20000	142	40	Yes	–	–
20	100	75	7.6	21000	132	40	Yes	–	–
22	111	79	8.9	23000	112	U2	Yes	–	Yes
22	86	74	9.5	27000	105	U2	Yes	–	–
25	125	86	11.52	25000	86	40	Yes	–	Yes
26	104	93	12.2	32000	82	U2	Yes	–	Yes
28	112	95	15.4	38800	65	U2	Yes	–	Yes
30	120	108	17.36	46750	58	U2	Yes	–	–
32	128	116	21.75	53120	46	U2	Yes	–	–
38	152	137	28.0	78990	36	Yes	–	–

High Quality Used Chain - from ships , inland waterway vessels and shipyards.

When offering new or used chain we are happy to send photos to show the quali- ty, alternatively we will be pleased to welcome you for an inspection visit.

Probably the best used chain available!

Used Chain – Second-hand Chain

Through our continued involvement with commercial shipping concerns we process large quantities of used chain annually. This chain comes from merchant ships that are being decommissioned or vessels that are replacing anchor chain to comply with maritime requirements. Much of it has little or no wear and is still very suitable for use in a variety of applications, including use as ground chain.

Used Chain is offered subject to availability varies in size usually from 24mm to 45mm in both open and stud link. It can be sold by weight or cut specific lengths suitable for its eventual use.

Why do ships use Stud-link anchor chain? Its because the ‘bar across the centre’ which is known as the ‘stud’ makes it heavier, weight is an important factor when anchoring ships, some of which are over 300 meters long, another factor is strength, when placed under enormous strain chain will bend inwards at the centre of the link, if this occurred whilst anchored, the ships anchor winch would be unable retrieve the deformed anchor chain, the stud prevents the chain from deforming.

What's New?

Over the recent past there has been amazing changes in the types of chain that are now used for mooring. The first UK move to improve the quality of mooring chain was the introduction by EYE Ma- rine Ltd. of Grade 40 mooring chains which were produced in Italy by ‘Maggi Catene’, (now part of ‘MF Catenificio Frigerio SRL’).

The latest tried and tested development is Grade 60 mooring chain.

Using the latest technology our Italian chain manufacturers have developed this high strength marine grade chain over a number of years, it has proved successful in various applications including aquacul- ture, floating pontoons, mooring systems and navigation buoy moorings. MF have called this type of chain ‘DAMS’ which stands for:

‘Downsizing Anchoring and Mooring Systems’.

The reasoning behind the introduction of this type of chain is that it allows the use of a lighter and smaller sized chain for mooring applications.