captain jonathan mills. noble denton marine assurance, dnvgl oil & gas - offshore rig moves from...
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DNV GL © 24th June 2015 SAFER, SMARTER, GREENER DNV GL © Noble Denton Marine Assurance & Advisory
24th June 2015
Captain Jonathan F B MIlls
OIL & GAS
Noble Denton Marine Assurance & Advisory
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Mobile Offshore Unit (MOU) Moves from the
Marine Warranty Surveyor & Towmaster Perspective
DNV GL © 24th June 2015
Noble Denton Marine Assurance & Advisory
Introduction
Marine Warranty – Why?
Marine Warranty – Wet & Dry Tows/Moves
The Towmaster & Marine Representative
Tow Vessel Suitability – First Impressions
Practical Challenges
Jack-Ups in Particular
MWS Approvals, Best Practice & Competency
Tow Vessels What to Look for Inside & Out
Constant Issues
Questions
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DNV GL © 24th June 2015
Noble Denton Marine Assurance & Advisory
Marine Warranty
A Marine Warranty Survey
is the Review, Supervision and
Approval of complex marine
operations such as “Rig
Moves” in the interest of
Client’s Insurance Company
and Underwriters.
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The extent of review and supervision is dictated by the insurers within their Warranty Clauses.
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Noble Denton Marine Assurance & Advisory
Marine Warranty
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MOU moves are basically of two types:
Wet Tow
Dry Transportation.
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Noble Denton Marine Assurance & Advisory
The Towmaster
The Tow Master, also known
as the Rig Mover, is
responsible for the
operational manoeuvring of
the MOU from one location to
another in accordance to the
approved towing plan.
The Tow Master instructs the
main and assist towing
vessels with regard to tow
wire deployment and the
various courses & speeds to
follow.
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Noble Denton Marine Assurance & Advisory
The Tow Master is not in
overall control of the unit and
the OIM at all times remains
responsible for the overall
control of the unit. The Master of
lead towing vessel is legally
responsible for the tow.
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Noble Denton Marine Assurance & Advisory
Marine Representative
Suitably experienced marine professional stationed on board the MOU who
represents the marine related interest of the Chartering Oil Company. Works
closely with, or reports directly to, the Company Man.
Ensures that the Oil Company’s applicable policies are adhered to at all times
during the move and installation of the MOU.
Ensures that the Oil Company’s assets are protected at all times.
Is responsible for monitoring all marine vessels under the responsibility of the Oil
Company.
Closely liaises with the OIM, Tow Master and MWS with regard to rig move
status.
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Noble Denton Marine Assurance & Advisory
Practical Challenges During MOU Operations
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Poor Performance by Main Towing and Assisting Vessels.
Towing and assist vessels should be
inspected prior to move to ensure they
meet all Class and Port State Regulations
as well as against established technical
standards
Competency of Crew – with particular
regard to towage experience
DNV GL © 24th June 2015
Noble Denton Marine Assurance & Advisory
Practical Challenges During MOU Operations
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Bad Weather Accurate, continual and reliable
weather forecasts from a reputable weather forecasting company (x2)
Local anomalies Weather Routing – good and bad Watertight Integrity Shelter Areas and Safe Ports
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Practical Challenges During MOU Operations
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Determining unpredictable motions in seemingly good weather
Deceptive long period swell can induce extreme motions on a rig
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Noble Denton Marine Assurance & Advisory
Practical Challenges During MOU Operations
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Geographical and Location challenges
Tow to pass under bridges, power cables etc. Tow to pass over shallow areas, reefs etc. River passages, TSS transits etc.
DNV GL © 24th June 2015
Noble Denton Marine Assurance & Advisory
Practical Challenges During MOU Operations
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Jack up installations – Punch Through, stability, mechanical failures etc.
DNV GL © 24th June 2015
Noble Denton Marine Assurance & Advisory
Jack-ups - Briefly
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Jack up is MOU comprising of hull, legs and jacking system such that it can be towed to a location, legs lowered into seabed and hull elevated to operating air gap.
Since the legs of jack up are supported by seabed, the soils have to be proven as a reliable foundation via preload operation which is simulation of maximum anticipated storm footing reaction by adding equivalent ballast weight.
DNV GL © 24th June 2015
Noble Denton Marine Assurance & Advisory
Challenges with Jack-Ups
Leg Run, Punch Through: Seabed soils
can be unstable during installation or
even after the jack-up is elevated
particularly due to the presence of
stronger over weaker soil layers. In
this type of soil, rapid leg penetration
or drastic drop in the soil resistance
(“punch through”) may occur. If not
anticipated properly, a punch through
can cause major structural damages
with severe consequences.
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Noble Denton Marine Assurance & Advisory
Challenges with Jack-ups
Interaction with Existing Footprints:
Many times jack-ups have to be installed
on disturbed seabed adjacent to or
overlapping with existing footprints. This
could lead to issues like leg sliding,
eccentric loading and rack phase
differences which results in difficulty
positioning the rig at the intended
location safely.
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Noble Denton Marine Assurance & Advisory
Challenges with Jack-ups
Scour: Scour is associated with
jack-up deployment on a sandy
seabed with high bottom current.
Potential erosion of the spudcan
bottom contact with the seabed
may lead to eccentric support
and settlement of the spudcan
which affect the jack-up
behaviour and potentially
compromise structural integrity.
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Noble Denton Marine Assurance & Advisory
Can be Mitigated by Integrated Structural & Geotechnical:
Leg Penetration Analysis
Punch Through Analysis
Site Specific Engineering Assessments
RPD Analysis
Spudcan Scour Potential & Protection Analysis
Seismic Assessments
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DNV GL © 24th June 2015
International Association of Marine Warranty Surveyors IAMWS
Established in 2013
Accreditation of MWS to minimum professional standard and code of ethics
Competency measured through testing and continuing professional development
Individual membership rather than tied to individual companies
Technical forum to share ideas, best practice and lessons learnt
Promotes open dialogue between MWS, underwriters and other stakeholders
Insurers & Underwriters have begun to assess the capabilities of MWS companies
– Local and global capability assessment
– Using pre-qualification criteria
– Scope of Work will state IAMWS accredited Surveyors
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DNV GL © 24th June 2015
Noble Denton Marine Assurance & Advisory
MWS Approval Process for Wet & Dry Tow
Class, Port State etc.
Calculation of Bollard Pull Requirement for the tow
Review the Main and Emergency Towing Gear strength
Inspection of Towing Vessels
Motion Response & Longitudinal Strength Checks
Cribbing Strength and Positioning
Seafastening
Stability
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DNV GL © 24th June 2015
Noble Denton Marine Assurance & Advisory
Check the vessels Class Certificates and the Towing Equipment
Certification first; that will give a good indication of the standard a
vessel is managed at.
PMS - CEO
Towing Log – Last Tow
Navigation Systems, Chart Corrections (Latest N to M)
ISM – DPA - Ask
Maritime Labour Convention – Rights, Complaints Procedure
Sanitary Certificate – 6 months
LSA & FFE Maintenance Logs
Certificates of Equivalency
DP Certificates and Log Books
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Tow Wires, Sockets, Pennants, Winches – Condition/Maintained/Op
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Towing Pins, Karm Forks, Shark Jaws, Stern Roller, Shackles
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Engine Room, Emergency Generator, Steering Gear & Thruster Spaces
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Bridge Equipment, Documents, Vision/View
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Constant Issues
HRU’s & Liferaft Service Dates – Correct Installation
Crane Certification
Engine Room & Steering Gear bilges
Housekeeping
Oxy/Acetylene Cylinders
Fire Hoses
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Noble Denton Marine Assurance & Advisory
Constant Issues
Watertight Integrity
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DNV GL © 24th June 2015
SAFER, SMARTER, GREENER
www.dnvgl.com
Questions
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Captain Jonathan F B Mills
+65 97 595441