Anchor chains play an essential role in the marine industry – with them, ships and vessels can stay safe and securely halted throughout their journey. If you want all the essential information regarding an anchor chain and how it works, this is the perfect place to start.
This FAQ guide will provide a comprehensive idea of the advantages, types, and other details of marine anchor chains.
Figure 1 Marine Anchor Chain
Marine anchor chains keep your ships safe. This heavy-duty chain is made to withstand the rough conditions out at sea: salt water, changes in temperature and salinity, and extreme pressure changes due to waves or rapid currents.
An anchor chain helps ensure that vessels stay in one place – whether used for travel, recreation, commercial fishing, or cruising. The chain is constructed from thick steel links connected using pins.
In some cases, additional pieces, such as shackles, might be added to parts of the chain for enhanced safety and strength. This chain is essential to make sure you can confidently head out onto the open ocean without worrying about getting swept away!
Figure 2: Chain Parts
A marine anchor chain – also known as an anchor rode – is a crucial component of the vessel’s anchoring system. Its purpose is to securely attach the anchor to a part of the boat so that it may be quickly and easily lifted in times of need.
Furthermore, this chain plays an essential role in deflecting specific forces away from the anchor head and main structure. When faced with extreme weather conditions such as storms or strong currents, a ship or offshore rig may tilt and heel uncontrollably, severely damaging its hull if not adequately protected.
Figure 3: Anchor Chains
Anchor chains are designed to absorb pressure placed on them, reducing the force exerted upon them. It allows for a potential decrease in damage caused by heavy weights as anchor chains and cables are manufactured to withstand substantial forces without harm or distortion.
Marine anchor chains are a lifesaver in keeping a vessel safe while it is out at sea. The chain connects the ship and the anchor, ensuring the boat remains safe from harm. Anchor chains are incredibly strong, allowing your boat to remain stationary amidst all weather conditions. Not only do they offer maximum strength, but they also feature an impressive level of corrosion resistance due to their construction with high-grade steel.
Figure 4: Anchor Chain in Water
In addition to this, marine anchor chains do not need to be replaced frequently like some other materials, making them cost-effective in the long run.
When selecting or creating the anchor chain, several essential elements must be considered.
When it comes to rode designs, it is essential to factor in convenience and ease during storage. Anchor chains need to be placed away carefully so that the hull of the boat is not damaged as a result of an anchor chain being left hanging down too much or entangling itself with other elements around it.
Every ship or offshore station has a good understanding of the depths of their working areas and can therefore determine the length at which the anchor rode should be securely attached.
The scope is a ratio that expresses the relationship between the amount of anchor rode paid out to the actual depth of the water body. It reflects a balance between how much vertical force an anchor exerts on a vessel and how much drift it experiences.
The scope of a ship’s anchor chain will usually range from a 5:1 to a 7:1 ratio, meaning that for every one foot of depth in the water, there will be five to seven feet of anchor line. Shorter chains are better at holding the vessel in place since they contain less slack, which helps prevent the waves’ natural motions from moving the boat away.
When the chain is released, and the angle between the anchor rode, and the bottom of the vessel is greater than 90 degrees, any sudden impacts or jerks are quickly transferred to both the rode and boat. This means that a more extensive range of motion can be achieved, and any force acting on the boat will begin to reduce in intensity. As a result, this allows it to drift into an area far more expansive than initially anticipated.
Check the video for some important tips to choose the right anchor chain:
If the design of a system involves both, it may be able to overcome some of the issues that arise due to the large number of variables involved in each design.
Figure 5: Combination of Chain and Cable
A cable and chain rode combination is commonly used in large cruise ships and offshore structures. This concept works because the chain components of the anchor rode are more suitable for use in areas with rougher seabeds, where cables cannot be used. The steel links within the chain sections have a higher tensile strength required to resist pulling force on the anchor and the ship, thus preserving the integrity of its position.
A typical anchor rode consists of a length of cable, usually made up of galvanized steel or stainless steel wire rope, connected to a short section of chain and then onto an anchor stock. For this reason, joining both types of rodes necessitates utilizing specialized techniques. It is at this junction between cable and chain where most failures occur due to its heightened fragility.
The junction between the cable and chain is covered with a galvanized connection, allowing for a secure and reliable interlocking of the two elements. The cable fibers are partially linked to the chain, creating an even stronger bond. It is further enhanced by being able to connect the cable to the chain as well directly.
Using this combination of cable and chain has numerous advantages. However, if not using such a combination in such conditions, then the single heavy chained element won’t stay on the seafloor due to its lack of weight anchoring it down. In addition, due to its sturdiness when connected, this combination can easily withstand strong waves or winds without coming apart or getting displaced from its anchored position at the seabed.
The importance of an anchor chain’s scope cannot be understated, as it is necessary to maintain a balance between the movements of the vessel and the strain that is placed on the cable or chain during anchoring. This means it is absolutely essential to be aware of how much anchor rode has been used. To this end, painted sections and plastic markers are strategically positioned along the anchor rode in order to help those involved in anchoring operations, such as the operator, identify quickly how much rope they have put into use.
Compared to traditional painting and other methods of marking the water, plastic rope markers have the advantage of having a longer life on the seas. The paid-out rope length can be typically shown by colored zip ties having different knots at various uniform intervals. These intervals lie between 25 feet and 7.5 meters.
As part of nautical norms, the colors used for length indicators tend to be white, red, and blue. Moreover, they can disintegrate if they come into contact with tethering spools and hawse pipes frequently.
The anchor chain serves an essential purpose in providing extra stability to the anchor, which is often made of metal. But due to being exposed to the harsh environment, these materials are prone to rust and wear over time, making them increasingly vulnerable. This is why it’s essential that when boats bring their anchors back onboard, they must scrutinize them for any signs of damage.
For this, appropriate storage facilities must be constructed so that the rode may be quickly retrieved for maintenance.
Inside the ship’s hull lies the chain locker: an enclosure specially designed to provide ventilation and store anchor chains when they are not in use. This space is typically reinforced with additional materials to support the heavy load of the metal rope and accompanying anchor that is often stored there. As needed, engineer staff can access the locker for regular inspections or maintenance services.
The locker itself is strong enough to withstand immense pressure and strain exerted by the heavy weight of the chain and its elements. Its walls are often made from thick steel plates or reinforced concrete, ensuring it will remain secure during harsh ocean conditions.
Figure 6: Chain Locker Location
It is critically important that the anchor storage equipment on a vessel is set up incorrectly, as it can lead to considerable danger if mechanical problems occur with the windlass. This windlass may offer power to raise or lower the anchor chain, so having an organized arrangement of port and starboard side anchors is essential. If this equipment is not set up correctly, there could be an unforeseen issue with the raising and lowering of the anchor chain.