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.

Boat Gear Direct are the cheapest in the UK for 6-10mm Non Calibrated Galvanised Chain, calibrated G40, and Stainless Steel 316 DIN 766. We offer cut to length and full making up service.

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
Short link chain uses compact links with an overall length no greater than five times the material diameter and an overall width no greater than 3.5 times the material diameter. A 10 mm short link chain should have a maximum outside dimension of 50 x 35 mm, with an internal size of roughly 30 mm in length and 15 mm in width.
This configuration is the strongest of the three, but the restricted internal width limits the size of shackle that can be used. It is rarely the best option for mooring systems unless it is welded into a bespoke assembly in our marine fabrication workshop.

Mid Link Chain
Mid link chain is slightly longer, with links no more than six times the material diameter in length and 3.6 times the diameter in width. A 10 mm mid link chain should not exceed 60 x 36 mm externally, with internal dimensions around 40 mm by 16 mm.
Mid link chain is a strong all round choice for moorings because it offers most of the strength of short link but accepts shackles with bodies that match the link diameter. This makes rigging easier and reduces weak points.

Long Link Chain
Long link chain has the largest link proportions, with overall length up to eight times the material diameter and width up to four times. A 10 mm long link chain is typically up to 80 x 40 mm externally, with internal space of about 60 mm by 20 mm. The key advantages of long link chain in mooring systems are its ability to take larger shackles and swivels, its lower weight for the same diameter, and the fact it is usually the most cost effective option. The reduced weight can also influence buoy choice, which matters when selecting a complete mooring setup.

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.