Gå til hovedinnhold

Better mooring, continued challenges

Over the past year, the Petroleum Safety Authority Norway (PSA) has noted several improvements in the area of mooring. However, there are still many incidents that could have been averted through better systems for training and sharing experience. The industry must keep up its efforts towards a general raising of standards for mooring equipment. The PSA will closely monitor developments in the months to come.


Links:
Mooring seminar 1 December 2005 (in Nowegian)
Relevant article: Notification of order following chain deployment on Ocean Vanguard 25 May 2005


Sprekk i ankerkjettingOn Monday, 3 December, the PSA organized an industry seminar to exchange experience and promote a debate regarding incidents and measures implemented over the past two years. (See all presentations in the link box).
The number of chain deployments, breakage in chains, couplings and fiber lines remains high. The PSA sees a need for better securing of necessary holding power in the anchors, and takes a positive view of the fact that the industry has now started to test the use of pre-installed anchors. has adopted safer mooring as a new high-profile issue. The Norwegian Shipowners' Association is responsible for this issue, and has prepared concrete goals intended to reduce the number of incidents. The PSA is monitoring the effectiveness of this program with great interest.

Management responsibility
The contribution made by management in the various companies' is among the PSA's priority commitment areas. Management involvement in preventing major accidents must also include shipping companies that operate mobile facilities and vessels. Management's responsibility for organizational factors, training of personnel and technical factors must be emphasized.
Raising the standard of equipment and competence will require both human and financial resources. Management has a particular responsibility for following up to ensure compliance with its own management systems.

Competence challenge
The industry faces significant challenges in training and educating a sufficient number of personnel to man the large number of new vessels that will become operational in the next two years.
In this respect, it is positive that the industry is also using simulator training to help meet these needs. In addition to the traditional education offered, some shipping companies have begun to use simulators both at the shipping offices and on board the vessels.

More remote control
Important work is being done in the vessel industry to improve working conditions for groups at risk. The use of new technology means that the crew is less exposed to risky work operations on the deck of the vessel. The industry has developed and is in the process of implementing various types of remote-controlled equipment and tools that enable crews to stay in safe areas.

In the same manner as the drilling industry has largely succeeded in automating operations on the drill floor, a comparable effort is needed for crews exposed to risk on the deck of the vessel.
In connection with development of new vessel technology, it is also important that players who operate in the interfaces, such as the supply bases and permanent and mobile facilities, implement measures so that modern equipment can be fully exploited. One example of this could be modernization of coupling options for loading hoses.

Deployment of chain from mooring winches
The regulations require that each mooring winch have two independent brakes engaged at all times. Both brakes would have to fail in order for the chain to deploy. The high number of incidents involving failure of both brake systems resulting in chain deployment indicates that the error frequency remains high.

The PSA believes that several of these incidents would not have occurred if the industry had better systems for training and exchanging experience. The crew should have better knowledge about how mooring winches and brakes function, as well as better training in evaluating the quality of the chain - so-called visual inspection.

Chains
The comprehensive effort to replace older chains in the past year is a positive development, in the opinion of the PSA. Fatigue breaks in anchor chains are caused by the chain being used too long, or that it has been exposed to damage - such as loose stud links.

As regards the latter, there have also been breaks in newer chains. The inspections and repairs in connection with certification and recertification are essential in order for the chain to meet the applicable quality requirements. This year, the PSA has intensified requirements for inspection of chains that are more than 20 years old.

Shackles
The PSA has registered about as many breaks in shackles as in chain links, and both types of breaks result in unintentional drift. Since the number of shackles is small compared with the number of chain links, each single shackle has a considerably higher breakage rate than the chain links. We believe that particular attention must be given to shackle selection, and in connection with evaluating the condition of the shackles. The PSA is pleased that the number of shackles will now be limited.

Fiber rope
Use of fiber rope may, in some cases, be beneficial in both safety and operational terms. However, fiber rope has proven to be very vulnerable to contact with steel wires. The PSA is of the opinion that the activities must be better organized so as to take the vulnerability of the fiber lines into account.

Anchor holding power
Before an anchor is used at a location, the anchor is subjected to a test load. For a number of years, this test load has been too light - with the consequence that the anchor has dragged. Experience has shown that anchor dragging can lead to breakage in the neighboring line. Drilling facilities are often moored in areas where there are many subsea facilities, so that dragging could damage other facilities.

The test loads have increased, and no anchor dragging incidents have been recorded in the past year. It is positive that analyses are being made of the consequences of dragging, so that this risk can be managed. Checks to ensure that the anchor has been properly set have improved significantly.

Raising standards and responsibility
Many of the mooring incidents on the shelf have occurred when the facility was connected to the well, or moored alongside another facility. The shipowner is responsible for the equipment on the facilities, and this is followed up through the AoC system. The operator is responsible for the site-specific evaluation, and this is followed up through the consent process.

Contact in the PSA:
Odd Rune Skilbrei

For press inquiries:
Inger Anda, press spokesperson
E-mail: inger.anda@ptil.no
Telephone: +47 970 54 064