Get Rid of Your Anchor Chain Problems Once and For All

Hey readers, we meet again with an exciting article! This time, it’s about the Anchors chains. It’s pretty interesting to know about these giant beauties of the sea. You get quite a lot of interesting facts about the ships and their tools. Let’s find out more about Ship anchor chain!

Anchor chain for ships

What exactly does an anchor chain do? Do we all doubt this? The primary purpose is to build up a mechanism for ships and boats to hold their position or place either during berthing and tie-up operations at ports. Also, the anchor chain has a significant role in large offshore installations such as semi-submersible oil rigs to remain still above an oil deposit.

Anchor chain for ships

How does an anchor do this? Let us explain through our experience. The anchor holds onto any rocks or debris at the bottom end of the ocean or sea. It provides an axle about which the ship will remain immobile.

The other central point is that anchors can also increase the drag of any vessel in situations where it is needed. They serve as an artificial drag mechanism when trailing behind the boat.

When we let the anchor follow in the ship’s wake, the entire vessel is steadied against any sudden wave motions during storms. It is a critical factor in avoiding green water loading or seawater entering the ship’ and bow crashing. If the vessel follows the anchor, a massive amount of extra load and indirect forces are absorbed from the ship’s hull. The containers can remain stable due to this mechanism of the anchor.

Anchor chain grades

Did you know that there are various categories of anchor chains? No one would have thought that the anchor chains could be graded. But they are.

There are several types of chains that we for the anchors.

Below are the most common types. 

  • G30 – Proof Coil is a general-purpose chain of standard commercial use, low-carbon steel. This type of chain does not have a uniform pitch, so it does not work well for windless purposes. Every foot of this chain is hallmarked with the manufacturer’s symbol and grade marking as 30 or 300 
  • BBB Anchor/Windlass Chain is a short chain of regular commercial quality. This chain is also constructed from low-carbon steel. Its uniform pitched short linked chain works well with gypsies. It was considered the standard for windlasses, but G4 Chain has largely replaced it. Like the proof coil, it is also hallmarked mostly every foot with the manufacturer’s symbol and grade marking: 3B
  • G4, G40, G43 -High Test is considered the standard chain for most windlasses today. These chains are considered highly durable as they are made of high-carbon steel. It can also cope up twice the working load of a BBB chain, allowing a smaller chain size to be used.

Every foot of this chain is also marked with the manufacturer’s symbol and grade marking: G4, G40, G43, or G400.

  • G70 – Transport- This chain is mainly called G7 or transport chain. It is a very durable chain with a very high strength-to-weight ratio. The test results show that it has about 25% more strength than high test chains. But it works with very few windlasses, however. The chain is hallmarked almost every foot with the manufacturer’s symbol and grade marking: 7, 70, 700.

However, there is a difference between the BBB and the G4 chains. If you compare the BBB vs. g4 chain, there is quite a difference in the length of a 3/8″ BBB chain link and a 3/8″ G4 chain link. The inner size of 3/8″ BBB is 1.09,” and the G4 is 1.22″. BBB has more joints or connections per foot than G4, so a given length of BBB weight is more than the same length of G4.

Parts of anchor chain

Though we think it is simple, an anchor chain has different features to make the ship stable. First, we need to get used to the details of the anchor. 

Before the metal anchor, ancient ships used other methods to make a boat stable. They were of large stones, basketfuls of rocks, sand-filled sacks, or wood logs filled with lead. These materials helped hold the vessel by their weight and friction along the bottom. 

But the vast steel anchors came into the scene as the ships became more bog and bulkier, serving various commercial purposes. The steel anchors have a standard shape and design. And we use these at the moment in most of the ships.

When you look at the parts of an anchor chainwe cannot just disregard the below.

Mainly, Iron replaced wood, and teeth or flukes were added to help the hooks dig into the bottom. Also, the addition of a stock or horizontal arm is essential, and its setting is crucial in the right direction to the arms and flukes of the lower part of the anchor. The store makes sure that the arms rest vertically on the seabed.

Due to this, one chance will dig itself in, generating maximum holding power. This type remained the primary anchor for many centuries with all its character and details. This type of anchor has many names, known as a stock anchor in the United States and a fisherman’s anchor in the United Kingdom.

Parts of anchor chain


But later in the 19th century, curved arms began to replace straight arms in anchors. We are still using this type for light work and boats. The ring (is the part of the anchor where the chain or cable is attached. If you need to remove the anchor, we take off the keep pin, and the stock can be removed from the head so that the anchor can be kept flat on an anchor bed in the ship.

But remember, before letting go, we need to ensure that one of the flukes digs into the ground. Usually, we call the vertical shaft a shank; it contains a balancing band fitted at the anchor’s center. It makes the anchor balance horizontally when lifted. The shank is joined to each arm at the crown. We call the part at the end of each component- a fluke. It consists of a triangular flat face with a pointed bill deep into the ground.

The stockless anchor is the other type we use. The unique feature is that a stockless anchor’s crown, arms, and flukes are cast in one piece and can pivot slightly from side to side on the shank. The chances of this anchor are long and heavy. It has projecting shoulders at its base that catches on the seabed. As more drug is applied, the shoulders force the flukes downward into the bottom. Today most large ships use these Stockless anchors on most of the large vessels of the world.

We should also know about the parts of the anchor chain or the marine chain. Below are the components that we can find in a standard anchor chain.

  • Common stud link of anchor chain.

It is an essential part of the intermediate shot of the anchor chain.

  • Enlarged stud link of anchor chain.

It is the additional link for connecting the anchor cable and end link.

  • End link for anchor stud chain.

This part is the last link of the anchor cable that provides the connection between the anchor cable and the end shackle. It connects anchor to anchor shot, and the anchor cable connects to the chain fastening device in a chain locker of a vessel or a ship.

  • Common studless link of anchor chain.

It is used to produce an intermediate shot of a studless anchor chain.

  • Enlarged studless link of anchor chain.

Enlarged studless link of anchor chain  is also an additional link connecting the anchor cable and end link.

  • End link for anchor studless chain.

It is the last link of the anchor cable that hat provides the connection between the anchor cable and the end shackle. These links connect anchor to anchor shot, and the anchor cable is connected to the chain fastening device in a chain locker of a vessel or a ship.

  • Connecting link (Kenter link)

This link is a detachable element specifically made to connect intermediate shots, anchor shots, and first shots into the anchor cable. It is manufactured by hot stamping with subsequent machining.

  • End shackle.

The end shackle is a detachable element that connects the anchor cable to the anchor and the chain fastening device. The pin of the anchor shackle is made out of an oval section To provide greater strength. And it is fixed in a bond with a dowel pin.

  • Swiswivel and swivel- shackles

The central part of the standard anchor shot is made to avoid the twisting or turning of the anchor cable when lifting and lowering the anchor.

Anchor chain dimensions

We normally pay much attention to the anchor chain dimensions. It depends on your anchor size and the weight of the ship.

Here are some facts that we follow as a rule of thumb. It states the 1/8″ chain diameter requirement for every 9 or 10 feet of boat length.

 e.g., 1/4″ which is now 6mm DIN766 chain would be up to 20- or 23-feet Yacht LOA, 7mm DIN766 chain would be up to 23 or 27 feet, 5/16″ now offered as 8mm DIN766 would be up to 27 or 31 feet Yacht LOA, 3/8″ now given as 10mm DIN766 and 10mm ISO would be up to 34 or 39 feet Yacht LOA.

Also, the 5/16″ US Specification (8.7mm) chain is now available from Jimmy Green Marine, and the simple rule would be up to 29- or 34-feet LOA.

This rule of thumb isn’t so far removed from the Jimmy Green Anchor Chain Size Guide, but it is probably based on the Grade 30 chain because Grade 40 is a recent advancement for yachting anchor chains.

Grade 40 Calibrated Anchor Chain is 25%+ stronger than Grade 30 Anchor Chain providing extra assurance and protection when conditions worsen. 

Anchor chain dimensions

Also below are the details put in a graph for your easy understanding. It nicely explains the anchor chain length.

  • Proof Coil [Grade 30]: is a general-purpose chain, mainly used for light-duty tow chains, tie-down chains, and logging chains. Links are more extended. Thus, the chain is more delicate than BBB and Grade 40 HT for a similar length.

 Proof Coil Chain Chain Size (in) Wire Diameter (in) Inside Length (in)
(Usually Grade 30)
    1/4 0.279 1
    5/16 0.342 1.1
    3/8 0.404 1.23
    1/2 0.512 1.5
    5/8 0.628 1.9
    3/4 0.779 2.2
  • BBB: Short, close links. The short link makes the chain more flexible and best suited for a windlass, usually made in Grade 30 only.

BBB Grade 30 Chain Size (in) Wire Diameter (in)
     1/4 0.274
     5/16 0.328
     3/8 0.392
     1/2 0.509
Inside Length (in) Inside Link Width (in) Inside Length (mm) Inside Width (mm)
0.87 0.43 22.1 10.9
1 0.5 25.4 12.7
1.09 0.62 27.7 15.7
1.34 0.75 34 19.1
  • ISO G43 Hi-Test Chain: Most common specification for Hi-Test Chain sold in the USA.

Iso G43 Hi-Test  Chain Chain Size (in) Wire Diameter (in) Inside Length (in) Inside Link Width (in) Inside Length (mm) Inside Width (mm)
     1/4 0.274 0.845 0.4 21.5 10.2
     5/16 0.33 1.03 0.49 26.2 12.4
     3/8 0.399 1.22 0.58 31 14.7
     7/16 0.467 1.4 0.66 35.6 16.8
     1/2 0.51 1.59 0.77 40.4 19.6

DIN 766 (Common Standard for Metric Chain)

DIN 766 Dimensions (Grade 70 and Grade 80 chains are usually DIN 766) Chain Size (mm) Wire Diameter (mm) Inside Length (in) Inside Width (in) Inside Length (mm) Inside Width (mm)
  6 6 0.73 0.31 18.5 8
  7 7 0.87 0.35 22 9
  8 8 0.94 0.39 24 10
  10 10 1.1 0.55 28 14
  11 11 1.22 0.55 31 14
  13 13 1.42 0.71 36 18

ISO4565 G70 Chain

ISO – G70  ISO4565 – (ACCO) Chain Size (in) Wire Diameter (in) Inside Length (in) Inside Link Width (in) Inside Length (mm) Inside Width (mm)
     1/4 0.279 0.87 0.441 7.1 22.1
     5/16 0.332 1.11 0.505 8.4 28.2
     3/8 0.404 1.226 0.576 10.3 31.1


The anchor chain weight is also something to consider about. HT chain is the heaviest chain that is being used. Its working load limit is doubled that of BBB, and it has the highest weight-to-working load ratio. The PC chain has an almost Similar working load as BBB.

According to the records, BBB was the most popular anchor chain because it’s made explicitly for windlasses. But its primary concern is its weight. A 100-foot length of 3/8-inch BBB weighs about 165 pounds, while identical sizes of HT and PC weigh 153 and 140 pounds simultaneously.

Also, the ships use anchor chains and ropes. The primary purpose is to keep the nylon rope from wearing away by rubbing it on the bottom of the seabed as the boat swings. Second, as the chain is heavy, it holds the rode to the bottom, so the pull on the anchor is horizontal, which decreases the chances of your anchor being unsetting.

Best anchor chain for saltwater

Do you know the best anchor chain for saltwater? According to the experience we have, it is better to use a galvanized anchor chain so that it will not rust. G4 galvanized is reputed to be one of the best chains.

There are many arguments about the stainless-steel vs. galvanized anchor chainLet us find out why!

The advantage of stainless-steel anchor chains is that they do not trust easily and are very smooth as they have undergone high-quality surface treatment. As a result, they fit themselves into the anchor locker as if by magic. But a galvanized chain is rough, and when lifting the anchor, it builds chain towers. If they get too high, they can block the winch.

Galvanized anchor chain

If you prefer to use a galvanized anchor chain for price reasons, you must be aware that frequently used galvanized steel chains on the seabed in the sand, on stones, or corals wear out very soon. With every contact, the zinc coating is damaged, and it usually takes only a shorter time than one season for rust to be visible for the first time.

If the rust lasts for a long time, the chain diameter is reduced! It will have a significant impact on long-haul sailors. One thing is the reduced holding force of the anchor chain. A rusted anchor chain is also not a lovely sight, and it inescapably leads to unpleasant rust building on the hull and decks up to a change of color in the area of the chain. You can re-galvanize a galvanized chain very quickly. 

As we know, the Cable anchor chains form the basis of the anchor chain. The aircraft carrier anchor chain weighs about 250 pounds! The standard size is 15 fathoms or 90 feet, a classic shot.

A navy ship anchor chain with an anchor can weigh more than 30,000 pounds in real life. Each link has 136 pounds and is 1440 feet long. 

Anchor chain markers

Marking the anchor chain is another main area for planning a voyage.

In the typical marking system, we use three colors three times each, first with one color used once, twice, then three times for each selected length, then the next color, etc. The colors can be made from paint or dye, standard on the chain, or ribbon or line, more common on the rope.

Why do you think the sailors mark the Anchor chain? It is a quick way to see how much scope you’re putting out in real-time. 

Anchor chain length calculator

Usually, the length of the anchor chain calculates through a system for more accuracy. Below are the critical points that we consider before calculating the distances.

  • Requirement of the minimal anchor chain length based on vessel characteristics and weather/sea conditions.
  • The anchor load and pulling angle at the anchor shaft.
  • Calculation through snubbers & bridles.
  • The Anchor Chain Calculator will tell you if the chain is insufficient and what effect this has.
  • Different vessel configurations that help to store under different names.

We will soon be able to calculate a mix of chains and ropes. There are also different anchor chain size charts that you can find easily online. Use a reliable site if you plan to do it through a system. Keeping the “scope of anchor cable formula “in mind will benefit. 

It is simple -Length of cable used in meters = 39 x√D – where D is the depth of water in meters. The ‘scope’ of the line is the ratio of the length of rope paid out to the water depth.

FAQs on anchor chains.

We thought it would be good if we could share a few frequently asked questions for your knowledge. It will help to clarify specific common concerns.

  • What size anchor chain for my boat?

Defining how long your anchor rode should be is as simple as multiplying the deepest water you expect to anchor in by 8. As for rope size, the rule of thumb is 1/8″ of rope diameter for every 9′ of boat length. If you expect to anchor your 26′ boat in 30′ of water, you need 240′ of 3/8″ nylon rope.

What size anchor chain for my boat

  • How to measure anchor chain size?

The anchor chain is measured in 2 ways. The thickness of the metal link and the length of the association are the two ways. The easiest and the most accurate method is to use a vernier caliper as a measuring tape is not 100% correct.

  • How much chain for an anchor?

 The chain will keep your rope from rubbing against the seabed and create the optimal angle between your ride and the seabed. The general rule is that you need roughly 1′ of chain for every 1′ of the ship. So, a 30′ ship would wish to 30′ of the chain.

  • How to tie a rope to an anchor chain?

The anchor hitch is ideal for connecting your anchor rope to the anchor. It does not loosen when tension on the line changes. It often happens when the ship rocks or the current of the wave changes. First, take the rope towards you and pass it through the anchor chain. It would be best if you repeated, giving the string through the anchor chain on the left of the first pass. You need to have two coils of the line through the anchor chain.

Get the end of the rope and bring it right so that it is between you and the chain. You may put the rope’s end through the coils from right to left and pull tight. The rope end should trap the vertical line that goes to the ship. To complete the anchor hitch, take the rope’s end and pass it from left to right around the vertical line to form a loop. Put the end through the loop and pull tight. It is called a half-hitch. Repeat one more time to make a double half-hitch. It will prevent the anchor hitch from slipping.

So dear readers, we hope you found the article helpful and exciting. We expect to meet you again with another exciting session on sharing knowledge!

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