Handbook of best practices

Figure 3.1 a: Oceanographic buoy recovery on the ship’s stern during mooring maintenance procedures.
Possibly, and depending on specific activities, the vessel should also be equipped with two
winches, to wind the mooring rope in the appropriate direction for the deployment. This is
very important with mooring lines of several hundred meters.
Additionally, a small boat (ship’s tender, such as a rubber boat) to operate close to the
surface buoy, can be essential to minimize the risks of damage for the instruments,
especially with rough weather conditions.
Well-equipped research vessels are of course the best choice to conduct such a complex
maintenance procedures: additional instrumentation such as CTD-rosette system, precise
positioning systems, dry and wet laboratories, multi-beam or large-range echo sounders,
guarantee the highest quality and safety of the operations, particularly when the instruments
used on the mooring line require specific quality control tests (e.g. CTD casts prior and after
mooring recovery/deployment, water samples for data comparisons, etc.).
[1] Consideration should be given to using non-toxic materials for oceanographic mooring
ballast. It is generally agreed that the environmental impact of leaving chain or concrete
ballast on the seabed is minimal. As nearly all deep water (typically water depths greater
than 200 meters) moorings are designed on the sub-surface single point principle that uses
in-line instrumentation and acoustic releases to recover the mooring, it is very difficult to
recover the ballast. Any significant change in mooring design or attempts to recover the
ballast makes the deployment and recovery operation inherently more risky. This does not
need to apply to moorings with a surface buoy and no sub-surface in-line instruments.
[2] Finally, the operations manager (e.g. chief scientist) and other accompanying personnel
are normally responsible for the following:
• Assuring that all mooring components and support equipment are loaded aboard the
ship as scheduled;
• providing all required service, repairs, or adjustments to the buoy, mooring, or
payload as required;
• completing a thorough buoy inspection prior to the ship getting under way to assure
the seaworthiness of the buoy;
• recommending proper deployment techniques to the captain of the vessel to reduce
the risk of fouling the mooring in the propeller or damaging the buoy and its sensors;
• preparing a complete and accurate report of the operation including all pertinent test
data and configuration control information, accurate documentation on the asdeployed
mooring configuration, and any changes made to the existing mooring;
• assuring that safety of personnel is the primary factor controlling the operation.
[1] OGP – “HS&E guidelines for metocean surveys” - Report No. 348, December 2003
http://www.ogp.org.uk/pubs/348.pdf
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