Maritime

Recommissioning of laid-up ships and mobile offshore units - how to avoid surprises

When the market moves back from a downturn, vessels are leaving the lay-up buoys and the focus shifts from preservation to recommissioning. DNV GL has accumulated its best practices into a revised Recommended Practice (RP) containing a new approach for assurance of non-class equipment and systems during recommissioning.

Technical Regulatory 03-2019 Recommissioning hydraulic
Picture 1: Hydraulic system in need of overhaul due to the acidity created after the wrong preservation liquid was applied
Technical Regulatory 03-2019 Recommissioning of laid-up vessels
Picture 2: From a survey report showing the implications of a lack of an essential preservation maintenance routine for a tug winch

Relevant for ship owners/managers, shipyards, flag states and insurance companies.

Through 2018 and to date we have seen signs of careful optimism in both the shipping and offshore markets. Based on Lloyd’s List intelligence, the number of inactive vessels has reduced – from about 850 vessels in early 2018 to some 800 inactive vessels as of today.

For many operators and shipyards with laid-up vessels, this has brought both opportunities and challenges in terms of how well the vessel has been maintained or preserved during the lay-up period. The quality of maintenance and preservation is a determining factor when bringing back the vessel effectively into operation. DNV GL has worked with a broad range of ship and MOU owners and operators on implementing cost-effective practices for preservation and recommissioning. Below are some typical challenges observed from this experience:

  1. The preservation execution log was not properly registered, and required actions for dedicated equipment and systems for recommissioning were not prepared systematically. This made it very difficult to prepare a good recommissioning plan.
  2. Compatibility of additive added to the system was not properly evaluated in advance. Some of the additives damaged the hydraulic system. Picture 1 shows a hydraulic system in need of overhaul due to the acidity created after the wrong preservation liquid was applied.
  3. Lack of turning/preservation for key rotating machinery was not covered by class scope. Hence, the system needed be completely overhauled /renewed upon recommissioning. Picture 2 was taken from a survey report and shows the overhauled condition of a tug winch after 18 months of cold lay-up without a proper routine of rotating and maintenance.

In response to market needs, DNV GL has recently updated its “DNVGL-RP-0290 Lay-up and recommissioning of ships and mobile offshore units” with a focus on industrial best practices for preservation and recommissioning.

The new, updated RP has introduced a dedicated section to respond to the challenges during recommissioning, with a focus on equipment not covered by class scope. The RP includes the following:

a) Guidance for lay-up
b) Guidance for preservation
c) Guidance for clean lay-up
d) Guidance for recommissioning
e) DNV GL lay-up services

Recommendations

It is recommended that vessel owners prepare the process carefully before reactivating their vessel. The DNVGL-RP-0290 contains best-practice recommendations for a successful layup and recommissioning process.

References

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