Welcome to our new column: “Not-So-Trivial Questions – Practical Answers for Mooring and Towing”
Posidonia has a century-long history, which started out as Neptunia and, since 1984, has carried on as Posidonia. We are a family-run business in its fourth generation, and for many of us, discussing chains, anchors, and mooring materials has always been part of everyday life. We grew up talking about these topics over breakfast, during family dinners, or even while catching up over a drink.
However, the maritime world isn’t always easy to get your head around. It has its own technical language, which can often feel inaccessible. Many terms, definitions, and applications are taken for granted, and that’s exactly why we’ve set up this column.
Through years of conversations with our customers, we’ve picked up on recurring questions—questions that may sound basic but often turn out to be crucial. Behind each term lie certifications, ISO standards, technical applications, and how components interact onboard. Misunderstanding a single term can bring about issues at sea or cause missed opportunities to benefit from innovations in marine engineering.
With this column, we aim to clear up doubts, provide practical answers, and pass on the expertise we’ve built up over generations to those navigating and working in the maritime sector. Welcome to “Not-So-Trivial Questions – Practical Answers for Mooring and Towing”!
If you have any questions or want to dig deeper into a topic, don’t hesitate to reach out—we’ll be happy to help. 🌊⚓
One of the most common questions we get is: What’s the difference between a stud-link chain and a studless chain?
In the maritime world, chains are categorized into two main types:
- Stud-Link Chains;
- Studless Chains.
Technical advantages
Stud-link chains come with a crossbar (stud) inside each link, which brings a range of technical advantages:
- Boost Strength: The stud strengthens the link, keeping it from bending under heavy loads, making it ideal for anchoring large commercial vessels or handling high-stress operations.
- Cut Down on Wear: By stabilizing the links, the stud reduces wear caused by friction between them.
- Ease Maintenance: The added rigidity makes inspections and upkeep easier to carry out.
- Prevent Tangling:The stud keeps the chain from twisting or getting jammed, ensuring smoother operation with winches and windlasses.
Typical Applications
- Large Vessels: Tankers, commercial ships, and mega yachts.
- High-Stress Areas: Situations requiring a high strength-to-weight ratio.
Posidonia’s Stud-Link Chains
- Manufactured to ISO 1704 standards;
- Available in standard lengths of 27.5 meters or customized to your needs;
- Offered in Grade 2 and Grade 3;
- Supplied with certification from any IACS body.
- Low Magnetic Permeability Chains.Grade 3 chains made from low magnetic permeability steel are a highly specialized solution for environments where magnetic interference must be minimized.
Studless chains, also known as calibrated chains, are lighter and more flexible than stud-link chains. They are a great fit for yachts and recreational boats, where weight reduction and easier handling are key.
Features of a Calibrated Chain
- Uniform Links: Dimensions (length, width, wire diameter) are precise and consistent, ensuring compatibility with standardized systems.
- Standards Compliance:Designed to meet international standards (ISO 4565, DIN 766).
- Winch Compatibility: Built to run smoothly on the gypsy of a windlass without jamming.
- Material and Treatment:Made from high-strength steel, often hot-dip galvanized for corrosion resistance in marine environments.
Posidonia’s Studless Chains
- Built to ISO standards (Pitch = 3xDiameter);
- Standard lengths available: 50, 100, 110, 127, 137.5, 150, and 165 meters (custom lengths available upon request);
- Available in: Galvanized steel; Stainless steel AISI 316 (mirror-polished optional);
- Supplied with in-house testing or certification by RINA or Bureau Veritas upon request.
