Site Specific Assessment (SSA)

Longitude provides engineering services relating to the location approval for jack up units. Our expertise in this field is a result of the significant experience of our marine and engineering staff with respect to the operational safety of these vessels.

Specialists in Site Specific Assessment

Longitude has developed an extensive in-house database of jack up units and together with our services relating to soil characterisation and evaluation, we are able to undertake site specific leg penetration and extraction studies.  Where required a full site-specific assessment can be undertaken taking into account both geotechnical and structural considerations.

Longitude Engineering undertakes our assessment to recognised codes, which include SNAME 5-5A and or ISO 19905-1.

Site Assessment Engineering

In order to assess the suitability of a site for jack up vessels, our engineers can provide the following assessments as part of a location approval by MWS:

  • Leg Penetration Analysis (LPA)
  • Site Specific Assessment based on ISO or SNAME Requirements
  • Punch Through Survival and Recovery
  • Dry Transportation Design and Verification
  • Scour and Leg Extraction
  • Site Spot Metocean Report
  • Site Zoning and Preload optimisation
  • Leg Seabed Impact Analysis
  • Operability Analysis

For floating units such as drillships and semi submersibles, we provide anchor patterns, mooring analysis, line profiles and riser analysis.

Mitigation Measures

Our experience enables us to recommend mitigation measures where the safety of jacking operations has been identified as a risk, these may be as follows:

  • Alternate Location
  • Reduction in Pre-Load
  • Operate in Weather Restricted Mode with ‘Cut and Run’ Approach
  • Jetting
  • Ground Improvement e.g. stomping or rock dump placement
  • Spud-can modifications

Key Contacts

Oil & Gas Market Lead, Longitude

London, Longitude

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Managing Director, Longitude USA


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Lead Geotechnical Engineer

Newcastle, Longitude

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