Mooring Knowledge Center
Technical guidance for mooring line selection and management
Written for superintendents, purchasers and masters — how mooring lines are selected against the ship design MBL, what MEG4 terminology actually means in a purchase order, how lines are inspected and retired, and what a rope certificate should tell you.
Selection
HMPE vs Polyester Mooring Rope
How HMPE and polyester mooring ropes differ in strength, weight, elongation, heat and abrasion tolerance, cost and handling — and when each is the right choice.
7 min readHow to Select a Mooring Rope
A practical selection sequence for mooring lines: design load first, then fibre, construction, diameter, length, terminations, tails and documentation.
8 min readRope Diameter vs Breaking Load
Why the same diameter gives very different break loads across fibres and constructions, why diameter is a poor way to specify rope, and what to specify instead.
5 min readMooring Tail Selection Guide
What a mooring tail does, why nylon is normally used, how tail strength relates to the main line, connection methods and when tails should be retired.
6 min readPolypropylene vs Nylon Mooring Rope
How polypropylene and nylon mooring ropes differ in strength, buoyancy, elongation, wet performance, heat resistance and cost — and which suits which job.
6 min readMEG4
What is LDBF in MEG4?
LDBF is the line design break force used in OCIMF MEG4 mooring line selection. What it means, how it differs from minimum break load, and how to use it when buying rope.
6 min readShip Design MBL vs LDBF
Ship design MBL is a property of the vessel; LDBF is a property of the rope. Understanding the difference is the core of correct mooring line selection.
5 min readInspection
Mooring Rope Inspection Guide
How to inspect mooring lines in service: what to look for externally and internally, which zones wear first, how to record findings and when to escalate.
8 min readWhen Should Mooring Ropes Be Replaced?
Retirement criteria for mooring lines: damage-based, use-based and age-based triggers, what an overload event means, and how to plan replacement instead of reacting.
6 min read