New terminology according MEG4

Creep
Creep indicates the time and temperature dependent deformation or lengthening under load. As synthetic materials are made of large, in the case of thermoplastics and elastomers, entangled molecule chains, these glide or disentangle under external load by which irreversible elongation occurs. This means that such ropes increase in length and will not return to the original length even when the load is removed (such as with HMPE ropes).

D/d ratio
The diameter of the bend (e.g. the roller or sheave) divided by the diameter of the mooring line. As the D/d ratio decreases, the greater is the negative effect that the bending has on the rope’s strength. A D/d ratio of at least 15 should be applied for HM mooring lines.Design basis load (DBL) Refers to the design load on a fitting. Calculated by multiplying the ship design minimum breaking load (MBL) by the geometric factor (GF).

dtex
dtex is the expression of weight in grams for filaments, yarns or twines of 10,000m length (g/10,000m). The higher the dtex number, the thicker the filament, yarn or twine. Elastic modulus The relationship between tenacity and elongation. The lower the elongation under load, the higher the elastic modulus. Elongation indicates by how much the rope will stretch under load. Unit of elongation is indicated in %.

Equipment Number
Ships will generally be assigned with an Equipment Number. It is derived through a complex calculation based on the vessel’s dimensions and specifications. The calculated Equipment Number then defines, for example, the required dimensions and strengths of the bollards, hawsers, anchoring equipment, towing lines and mooring lines that are to be used with the vessel.

Fatigue
The weakening or failure of a rope or other material during alternate tension-tension or tension-compression cycles. May be caused by internal abrasion or damage to fibres due to compression. Geometric factor (GF) The factor by which the line tension is multiplied to take the angle through which a line is deflected around a fitting into account. The wrap angle is defined as Θ, then the theoretical GF is GF = 2 sin(Θ/2)

High Modulus (HM) synthetic fibres
The generic term given to a range of fibre materials that include Aramid, LCP and HMPE fibres.

High Tenacity (HT)
Ropes made from High Tenacity fibres are made from Polyester, Polyamide, Polyester/Polyolefine mix. The tenacity of these fibres is less than 9 cN/dtex. The elongation at break is between 10 and 28%.

Line design break force (LDBF)
The minimum force at which a new, dry and spliced mooring line will break at, when tested according to Appendix B of MEG4

Line management plan (LMP)
The LMP outlines the ship operator’s requirements regarding the maintenance, inspection and retirement of mooring lines throughout the operational phase of the mooring lifecycle.

Minimum break load (MBL)
Describes the maximum force a length of new rope can be exposed to, under a straight pull, until it breaks. Safe working load (SWL) The usual working load of a rope in use. The working load is determined depending on the type of application. In most applications, 1/5th the break load is customary.

Ship design MBL
Refers to the minimum break load of new, dry mooring lines for which a ship’s mooring system is designed, to meet OCIMF standard environmental criteria restraint requirements. It is the central parameter against which all other mooring system components of the ship are dimensioned and designed with tolerances.

Specific tensile load
Refers to the maximum tensile force that can be subjected to a filament, yarn or twine before it comes to a break. It enables a direct comparison to be made between filaments, yarns and twines of varying fineness. The unit of measurement is cN/dtex.

Working load limit (WLL)
The maximum weight/strength a fibre rope can be subjected to in general use.

Safe working load (SWL)
The usual working load of a rope in use. The working load is determined depending on the type of application. In most applications, 1/5th the break load is customary.
Ship design MBL
Refers to the minimum break load of new, dry mooring lines for which a ship’s mooring system is designed, to meet OCIMF standard environmental criteria restraint requirements. It is the central parameter against which all other mooring system components of the ship are dimensioned and designed with tolerances.

Specific tensile load
Refers to the maximum tensile force that can be subjected to a filament, yarn or twine before it comes to a break. It enables a direct comparison to be made between filaments, yarns and twines of varying fineness. The unit of measurement is cN/dtex.

Working load limit (WLL)
The maximum weight/strength a fibre rope can be subjected to in general use.

info@blackrope.com , (+30) 69522 90682-3-4