DNV DNV-RP-E304 PDF

Application of the recommended practice

The purpose of this recommended practice is to provide assessment basis for the suitability of a polyester mooring rope to remain in service, after it has been mechanically damaged by external objects.

The recommended practice is applicable to any "parallel-subrope" type of rope. The inputs required to perform the necessary calculations are provided by the rope manufacturer. This information is given in the Manufacturer's Report.

The damage assessment is based on the subrope-to-rope relationship, since the subrope is the primary building block of the rope. Subrope-to-rope assessment is required since the effect of damage is highly dependent on the damage distribution.

This implies that for a given loss of area, the resulting rope strength and fatigue performance will vary depending on the distribution of the damage.

The result of the damage assessment is a revised minimum breaking strength MBS, denoted MBS_DAMAGED.

This (revised) MBS_DAMAGED is used to determine if a damaged rope is suitable for temporary or prolonged service, and use of this guideline shall provide documentation for that decision.

Prolonged service may be possible if the fatigue performance of the damaged rope is deemed satisfactory.