The Cygnus pioneered technique is recommended by Class societies when measuring through coatings, as perfectively good coatings do not have to be removed.

Measurements are stored through a versatile flexible data entry system. Templates can be set up to cover any application on board and the results, are in a format compatible with standard software packages.

The Cygnus 3 Datalogger is supplied as a complete ready to use kit, including probe, software and spare parts.

MJInformation No: 18218 Dutch dredging and marine contractors Van Oord ACZ have commissioned the world's largest flexible fall pipe vessel (FFPV) following its conversion from a bulk carrier at the Keppel-Verolme Shipyard in Rotterdam.

The self-unloading bulker Kvitnes, built by the J J Seitas yard in Hamburg, was less than two years old when it was transformed into the Rocknes, a 166.3m LOA behemouth which with a 25,000 tonne FFPV loading capacity, exceeds that of the previous largest FFPV by some 40%.

The conversion is the latest venture in the 20 year relationship between Van Oord ACZ and the Norwegian Jebsen Group and is the result of a combined effort to achieve highly efficient, cost effective offshore rock placement.

In addition to its massive loading capacity, the Rocknes' production output has also been improved and its systems adapted for minimal, efficient maintenance.

Fall Pipe Vessels like the Rocknes are generally capable of placing sand and rock in both shallow and deep water. The Rocknes is designed to work to a depth of 1,200m with extreme accuracy. This is achieved by letting the material fall through a flexible fall pipe, a tubular structure whose length can be adjusted to the working depth.

Material is then discharged only a few meters above the seabed.

A powerful cylindrical shaped remotely operated vehicle is installed at the lower end of the fall pipe to funnel the sand and rock material. The ROV is equipped with the latest survey equipment such as subsurface positioning, sonar sensors, cameras and monitoring equipment. With the benefit of the flexible fall pipe, the operating crew is able to place material most efficiently and accurately and with minimal spillage. Rockberms may also be installed to provide a foundation for offshore structures in areas where soils are not suitable or the seabed is very irregular. This environmentally friendly solution for the protection of subsea structures has been applied extensively in the North Sea but is now gaining more attention in other parts of the world.

For all activities during pre-installation, installation and post-installation, a very accurate positioning system based on Real Time Kinematic (RTK) GPS, used in combination with DGPS receivers and subsea transponders, is used to feed the Dynamic Positioning system in order to ensure maximum accuracy.

MJ Information No: 18219