This Annex describes the recommended site-assessment practice for jack-ups operating in the Gulf of Mexico during hurricane season.
The jack-up’s manned site assessment criteria assume the rig can be evacuated within a period of time, typically 48 hours, prior to the arrival of a Tropical Revolving Storm. This Annex is to be used in conjunction with the current revisions of SNAME Technical & Research Bulletin 5-5 “Guidelines for Site Specific Assessment of Mobile Jack-up Units” (Guideline) and Bulletin 5-5A “Recommended Practice for Site Specific Assessment of Mobile Jack-up Units” (5-5A).
The purpose of this Annex is to provide technical modifications to these references and to address unique characteristics of the Gulf of Mexico site assessment approach. The assessor may alternatively use both the Guideline and 5-5A. The Gulf of Mexico is unique in that it is a relatively benign environment except when a major hurricane enters the region. Modern forecasting and storm tracking techniques generally provide a significant warning period in advance of the arrival of severe weather, except perhaps when a Sudden Tropical Revolving Storm (TRS) forms within the Gulf (sudden hurricane). The standard practice is to evacuate all personnel prior to the arrival of severe weather. In the case of a sudden TRS it may not be possible to evacuate personnel; however, historical met-ocean data indicates that tropical storms or hurricanes that develop within the Gulf are much less severe than the major hurricanes that develop in the Atlantic basin and migrate into the Gulf. This Annex addresses both the major hurricane situation in which the jack-up is assumed to be unmanned and the sudden TRS situation where the jack-up may be manned, but the storm potential will be much less severe. Site Assessment for Winter Storms should use the 5-5A approach.