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www.marinelink.com 45mation to verify the design of the asset and provide input into fatigue calcula-tions for mooring lines and risers. Cur- rently, Þ nite mathematical modeling is carried out when designing the riser conÞ guration for the FPSO, but what is often lacking is the robust data to vali-date the actual local environmental con-ditions. Feeding this data into the design process can help to validate the accuracy of the modeling tools being used and re-duce uncertainty. The standard sensors and parameters that should be measured within the sys-tem include:? Meteorological ? the monitoring of the meteorological conditions offshore is critical to ensuring the safe operation of the asset. In 1981, the Civil Aviation Authority (CAA) and the Helideck Cer- tiÞ cation Agency (HCA) introduced the CAP 437 standard for the U.K. Conti- nental Shelf and currently recommends that meteorological parameters and mo-tion of the helideck are measured for an FPSO. Such parameters provide critical operational information which is sent back to shore so that companies planning any crew changes or helicopter opera-tions are fully aware of the weather status on the vessel before dispatch. Safety of employees is of the upmost importance, therefore companies want to ensure safe take-off and landing conditions ? Wave monitoring ? wave induced loads are the main source of fatigue for FPSO design and wave height is a sig-niÞ cant factor to consider for the design of the risers, as well as assessment of mooring fatigue life and hull integrity. Recording the extreme events in storm conditions also provides valuable input to the marine forensic investigation of any offshore incident ? Ocean current ? Surface currents can impact any ofß oading operations from the FPSO to the shuttle tankers and inß uence the response of the risers and moorings, resulting in fatigue loads ? Position and attitude ? measure-ment of the position of the FPSO is es-sential in storm periods to understand the vessel response to environmental forcing and the coupling of the resultant fatigue on risers and mooring lines. The posi- tion of the vessel is also critical in the assessment of any marine incident? Riser monitoring - a detailed un-derstanding of the environmental forc-ing to the FPSO combined with the riser response can aid the design process and provide the input to fatigue calculations ? Hull monitoring ? stress induced in the deck and hull of an FPSO can be monitored using a series of long base strain gauges positioned in strategic lo-cations on the deck and ß are tower. In addition, pressure sensors installed in the hull provide information on the vertical acceleration of the FPSO? Mooring line ? monitoring the mooring line is challenging and there is a scarcity of long term in-situ observed data sets for mooring line tension. For forensic engineering and validation of design codes, it is essential that mooring line tension is collected simultaneously with metocean parameters on a common time base.Each of the components mentioned ) O R 6 F D Q , Q V W U X P H Q W & R , Q F _ 6 H D W W O H : $ 8 6 $ _ H P D L O V D O H V # I O R V F D Q F R P I R U T X R W H V Read the Case Study Z Z Z I O R V F D Q F R P MR #10 (42-49).indd 45MR #10 (42-49).indd 4510/2/2013 4:31:48 PM10/2/2013 4:31:48 PM
