API RP 95F:2006 pdf download
API RP 95F:2006 pdf download.Interim Guidance for Gulf of Mexico MODU Mooring Practice- 2006
Hurricane Season.
9.2 LOOP AND EDDY CURRENTS
When a MODU is in a loop or eddy current, the Drilling Contractor and/or Operator must determine (he mooring line adjustments required to maximize mooring line safety factors under combined loop/eddy and hurricane conditions. Adjustment of the mooring lines becomes a matter of abandoning the MODU in a condition that provides its best chance of riding out the storm with due consideration to the existing surface current Velocity and direction.
Note: The Drilling Contractor and/or Operator should obtain the thllowing information:
Existing line payouts and tensions
• Latest nieasureincnls of the currents, pwticularly velocity and direction at the sea surface
• Any forecasts of the Ioopieddy current velocity and direction
The Drilling Contractor andor Operator shonld determine the optimum line payouts and/or pretensions that serve to maximize intact mooring line safety factors without exceeding equipment limits or endangering human life. The envimnmenial conditions used for analysis should include the following weather combinations:
• Omnidirectional hunicane metocean criteria should he used
• I lurricane-driven surface currents should be vectorially added to the local eddy current
• The payouts and/or pretensions shøuld he updated a’. surface current headings or velocities change
9.3 MODU RECOVERY
All units should be prepared to the extent feasible tir towing. Each MODU should be equipped with a primary and secondary line. Transportation and marine vessels should receive priority allocation in any recovery operations immediately following passage of a hurricane for the purpose of MODU recovery.
9.4 CONTINGENCY PLANNING
Contingency plans shall address operations identified as critical to both hurricane survival and resumption of normal activities. The contingency plans shall address the need to have suitable personnel available to respond to the problem at hand. For example, if a mooring winch is inoperable and cannot be repaired. then it is necessary to have a mo ring analyst determine suitable payouts and/or pretensions on the remaining lines that maximize survivability.
9.5 MODU TRACKERS”
Satellite location transponders shall be installed and tested on board all moored MODLJs operating in the Gulf of Mexico. These transponder systems shall be function tested prior to Hurricane Season to ensure the system is functioning propedy. Sufficient care shall be given to ensure these systems have adequate battery backup to enable the transponders to function after the MODU has been abandoned for a minimum period of seven days. Sufficient battery life should allow for reasonable assurance that the system will be operational through a given Hurricane Event and for a period of time after potential passage of the storm, to allow for speedy recovery operations in the event of mooring failure. The tracker system should be fully operational with seven day capacity within 48 hours of reboarding the MODIT.
Redundancy in systems should be considered.
9.6 RESPONSE PLAN
MODU tracker data shall be made available to the USCG as one element of a comprehensive response plan. The information update frequency and content shall be defined in the response plan.
9.7 POST-STORM DATA
For all MODU’s exposed to6O knot winds (I-minute at 10 meters) or greater during a storm, the Drilling Contractor should fill out an information forni capturing the MOI)L3 particulars and any storm related consequences. Appendix Ill contains a form that may be utilized for this purpos.APl has granted license, without restriction, for reproduction of Appendix Ill for this purpose.
9.8 STACKED MODUS
These guidelines siniilarly apply to MODUs that are not working and “stacked.” MODUs that are not actively working should be moored in accordance with the provisions of this document to minimize the likelihood of breaking free and inflicting damage.
