FPSO_Technical Specification for Marine Transportation

R:\Bonga\Clerical\Specs\Structural\BongaST007c(Supp 55 Marine Trans).doc Page 1 of 11

REVISION RECORD SHEET

C 15-Sept-99 Revised per Cost Challenge – Issued for Bid SM SM BJB

B 4-Dec-98 Issued for use on the Bonga Project SM SM BJB

A 21-Oct-98 Initial Issue – For Client Review and Approval SM SM BJB

Rev. Issue Date Description of Revision ENGRAPPR.

PROJ.APPR.

SDDSIApproval

Shell Deepwater Development Systems, Inc.Bonga Project

Document Title:

Supplement 55 – Technical Specification for Marine Transportation

DocumentNumber

BONGA – SPEC - ST - 007

Rev. No.

C

Page Total (Including this Cover)

11

Shell Deepwater Development Systems, Inc. Doc. No. Bonga-SPEC-ST-007Bonga Project Revision CSupplement 55 - Technical Specifications for Marine Transportation Date 15-Sept-99


Shell Deepwater Systems Supplement 55

Technical Specification for Marine Transportation

Shell International Exploration & Production Inc.

Issue 1.0

September 21, 1999



Shell Supplement 55

Technical Specification for Marine Transportation

DOCUMENT CONTROL SHEET

Reviewers: Roy Backstrom SIEPW. R. Ulbricht SDSJ. G. Mayfield ConsultantF. Bright SDSD. M. March SIEP

Issue Date Description Prepared By: Approved By:

1.0 September21, 1999

Issue for Use K. A. Digre W. L. Luyties

Signatures



TABLE OF CONTENTS

Section Description Page

1. GENERAL 5

1.1 SCOPE 51.2 DEFINITIONS 51.3 APPLICABLE DOCUMENTS 51.4 CONFLICT RESOLUTION HIERARCHY 5

2. TRANSPORTATION ENGINEERING AND PLANNING 6

2.1 SCOPE 62.2 LEVEL 1 TRANSPORTATION ENGINEERING 62.2.1 Environmental Transport Criteria 62.2.2 Transport Analyses 62.2.2.1 Strength Analyses 72.2.2.2 Fatigue Ana1yses 72.3 LEVEL 2 TRANSPORT ENGINEERING 82.3.1 Design Methods and Criteria 82.3.2 Localized Forces Introduced by Seafastening 82.4 COMMON TRANSPORTATION ENGINEERING REQUIREMENTS 8

3. MARINE EQUIPMENT 9

3.1 CARGO BARGES 93.2 TOWING TUGS 103.3 SPECIAL TRANSPORT VESSELS 10



1. GENERAL

1.1 SCOPE

This Technical Specification (Supplement) covers the transportation requirements forhulls, deck modules, vessels and subassemblies thereof, such as any tendons, buoyancytanks, rig components, riser assemblies, deck cranes and foundation piles.

1.2 DEFINITIONS

The following words used in this Supplement have specific definitions as follows:

"Component" shall mean the “Vessel”, hull, deck or deck modules, any subassembly ofthe hull or deck, tendons, or foundation piles.

"Drawings" shall mean the Approved Drawings and revisions thereof which define thesystem configuration in enough detail to allow material order and construction.Depending on the specification documents invoked by the CONTRACT, these mayalternatively be referred to as Approved for Construction Drawings (AFC Drawings).

"Transporter" shall mean the CONTRACTOR with responsibility for the transportationof the Component under consideration.

“Vessel” shall mean a combined hull and deck and/or deck modules.

1.3 APPLICABLE DOCUMENTS

In addition to conformance with this Technical Specification, the Marine Transportationportion of the Work shall be in accordance with referenced sections or paragraphs of thefollowing codes, specifications, publications and standards that shall be a part of thisTechnical Specification. Where reference herein is not limited to a specific section,paragraph, or topic, the entire Applicable Document shall be considered referenced.

a. American Institute of Steel Construction, Inc. (AISC), "Manual of SteelConstruction, Allowable Stress Design," Ninth Edition, 1989.

b. American Petroleum Institute (API), "Recommended Practice for Planning,Designing and Constructing Fixed Offshore Platforms," API RecommendedPractice 2A, Twentieth Edition, 1993.

c. American Bureau of Shipping (ABS), "Rules for Building and Classing MobileOffshore Drilling Units" (MODU Rules), 1991.

CONTRACTOR shall maintain copies of the referenced or applicable portions ofApplicable Documents at locations readily accessible to work sites.

1.4 CONFLICT RESOLUTION HIERARCHY

In case of contradiction between AFC Drawings, Specifications (including thisSupplement), or Applicable Documents, the following resolutions shall apply:

a. In case of contradiction between AFC Drawings and Specifications orApplicable Documents, the AFC Drawings shall govern.



b. In case of contradiction between any Specification and an Applicable Documentreferenced therein, the Specification shall govern, except as noted below.

c. In case of contradiction between lawful governmental regulations and, AFCDrawings, Specifications, or any referenced Applicable Document, thegovernmental regulations must govern if more stringent, regardless of whethersuch regulations are included in the referenced Applicable Documents.

d. In case of contradiction between referenced Applicable Documents, the morestringent requirement shall govern.

2. TRANSPORTATION ENGINEERING AND PLANNING

2.1 SCOPE

Planning for the tow is documented with a Marine Design Premise and a MarineTransportation Manual.

The Marine Design Premise defines and fully describes engineering to be performed byTransporter in preparation for the tow. The premise also identifies and justifies anyassumptions plus all design criteria.

The Marine Transportation Manual includes detailed engineering data for the marineequipment, other reference material useful to a tow master and a detailed towing plan.

2.2 LEVEL 1 TRANSPORTATION ENGINEERING

This section applies to Components identified in the CONTRACT - Scope Of Work or onthe AFC Drawings as requiring Level 1 Transportation Engineering.

2.2.1 Environmental Transport Criteria

For Strength Analysis. Transporter shall develop environmental transportcriteria for the purpose of Strength Analyses. The environmental transportcriteria shall include significant wave height, mean zero-crossing period andmean hourly wind speed.

The return period of the environmental transport criteria will be the return periodof the environmental conditions that have no more than a 5% chance of beingexceeded during the tow duration. (For example, if the most severe winterstorms in a region occur during a 3 month season, and the tow is entirely in thatseason and region and has a duration of 6 weeks, then a 10-year return periodwinter storm would satisfy the 5% requirement.)

The planned route and the time of year during which the tow will be conductedwill be considered in selecting these environmental conditions. Any studiesperformed shall be included in the Marine Transport Design Premise.

For Fatigue Analysis. For tows originating from sites that are not located on theU.S. Gulf Coast, Transporter shall also provide environmental data adequate forperforming a detailed transport fatigue analysis. These environmental data shallbe included in the Marine Transport Design Premise.



2.2.2 Transport Analyses

2.2.2.1 Strength Analyses

Transporter shall check the transport stresses in the transport vessel andin the Component's primary structure and design seafastening using theenvironmental transport criteria. Motions shall be computed in thefrequency domain utilizing spectral analysis with appropriate wavespectra and linearization of the transfer functions. The highest 1 in1000 waves response for each degree of freedom shall be determinedfor three seastate approaches: head seas, quartering seas, and beamseas.

Inertial and gravity loads due to the individual responses shall becombined as follows and applied to Component using a static structuralanalysis program:

HEADINGSURGE SWAY HEAVE ROLL PITCH YAW

Head Yes No Yes No Yes Yes

Quarter Yes Yes Yes Yes Yes Yes

Beam No Yes Yes Yes No Yes

In addition, direct wind force and the gravity load due to vessel heelunder wind load shall be added in the appropriate direction, assumingwind approach is identical to seastate approach. The design wind forceshall be computed using a one minute average wind speed and othercriteria per ABS MODU Rules.

Loads calculated for the design of the seafastening shall provide for theeffects of buoyancy and slam on any parts of the Component whichmight become submerged as a result of the vessel motions. Submergedseafastening members shall be designed for slam loads.

Transporter shall verify that bending moments in the transport vessel atall points along its length are within allowable levels, as specified bythe vessel owner or classifying authority, for the conditions prescribedfor Level 1 Transportation Engineering.

2.2.2.2 Fatigue Analyses

The objective of any fatigue analysis will be to demonstrate:

a. That the cumulative transport fatigue damage at any locationin Component in conjunction with the in-place fatigue damagedoes not exceed the allowable damage.



b. That the calculated fatigue lives of the seafastening membersand connections are at least five times the anticipated transittime.

The results of the analysis may require modifications to the towingplans, specifically with regard to the proposed tow route, proposeddeparture date, structural configuration, transport vessel, or other keyvariable. Transporter and Shell shall jointly decide on the appropriateremedial action.

2.3 LEVEL 2 TRANSPORTATION ENGINEERING

This section applies to Components identified in the CONTRACT - Scope Of Work or onthe AFC Drawings as requiring Level 2 Transportation Engineering. However, Level 1Transportation Engineering may be substituted where Level 2 is specified, atTransporter's option.

2.3.1 Design Methods and Criteria

Transporter shall design the seafastening for forces calculated with the equationsshown on Figure 2.3.1 assuming the following barge response criteria. Both aroll and a pitch response case shall be considered individually to determine thecontrolling design forces.

a. Roll Forces

Roll Angle = 20 degrees (single amplitude)Roll Period = 10 seconds (double amplitude)Heave Acceleration = 0.2 g

b. Pitch Forces

Pitch Angle = 12.5 degrees (single amplitude)Pitch Period = 10 seconds (double amplitude)Heave Acceleration = 0.2 g

Additional forces caused by wind shall not be added to these values. Thestructural framing and geometry of the entire system (i.e., barge, Component,and Component's support system) and the sequence of application of the forcesshall be considered in the distribution of these forces.

2.3.2 Localized Forces Introduced by Seafastening

The Transporter shall check that the Component and the barge deck are locallycapable of withstanding the forces being introduced by the seafastening. Shellwill accept responsibility for the remainder of the transport design of theComponent, provided any design assumptions included on the AFC Drawings orin the CONTRACT - SCOPE OF WORK are not violated.

2.4 COMMON TRANSPORTATION ENGINEERING REQUIREMENTS

This section applies to both Level 1 and Level 2 Transportation Engineering, and itsrequirements are in addition to those contained in Sections 2.2 and 2.3.



Stresses in the Component and seafastening shall be computed using the methodsdescribed in API RP 2A. Stresses that include the inertial forces resulting from thedesign environment shall not exceed AISC allowable values with a one-third increase inallowable stresses. Static stresses calculated for the seafastened configuration with noenvironmental loads shall not exceed AISC allowable values without the one-thirdincrease.

For cases where the Component's dead weight is transferred directly to the barge (e.g., asa module on launch skidways or a pile section resting on the deck of the barge), slidingfriction between the Component and the barge shall not be considered to reduceseafastening loads.

The seafastening shall carry the entire horizontal force. At a minimum, the seafasteningshall also be designed to carry a portion of the inertial vertical force in proportion to therelative vertical stiffness’ of the seafastening and the structure (or surface) which directlysupports the Component. If the seafastening also functions as the Component's supportstructure (e.g., cradles), the seafastening shall carry all of the vertical forces (dead weightplus inertial force).

Shell may elect to perform transport analyses similar to those being performed byTransporter. The results of the analyses will be compared as a check on the work of bothparties. A joint effort shall be made to determine the reason for any significantdifferences. The differences shall be resolved before the Marine Transportation Manualis finalized.

Seafastening material shall be tubular or structural shape. Wire rope or chain shall not bepermitted as the primary seafastening material, except for foundation piles and shippedloose items.

If acceptable locations for attachment of seafastening members are not explicitlyindicated on the AFC Drawings, Transporter may request guidance from Shell prior tosubmittal of the initial seafastening drawings.

3. MARINE EQUIPMENT

Requirements for major items of marine equipment are indicated in the following paragraphs.

3.1 CARGO BARGES

Cargo barges furnished for the transport of Components shall:

a. For transport from a U.S. port to another U.S. port - be U.S. fabricated and U.S.flagged vessels, unless it is clearly demonstrated that the use of foreignfabricated and/or flagged vessels will not be in violation of the Jones Act.

b. Be in a seaworthy condition and classed by one of the recognized classificationsocieties for the purpose intended. Bulkheads shall be watertight where shownon the Drawings and manhole covers intact, secured, and watertight. Costs forremedial work to bulkheads and manhole covers are the responsibility of theTransporter.



c. Satisfy the intact and damage stability requirements set forth in the ABS MODURules, when loaded with Component. The 100 knot wind requirements may bereduced to 70 knots for an inland tow.

d. Be delivered in a gas free condition with clean decks and dry tanks.

e. Have allowable deck load capacities of not less than 1500 pounds per squarefoot.

f. Be equipped with navigation lights and towing shapes which comply withapplicable governmental regulations.

g. Be equipped with a two-leg towing bridle in good condition, which shall beattached to suitable towing padeyes on the barge. Each leg of the bridle shallhave a minimum breaking strength of not less than 2.5 times the certified staticbollard pull for the attached towing tug.

h. Be equipped with a suitable emergency tow wire in good condition with aminimum breaking strength of not less than 2.5 times the certified static bollardpull of the towing tug. The emergency tow wire shall be fitted with a trailablepick-up line.

i. Be structurally suitable for all expected loading conditions. Barge stresses shallnot exceed the allowable values set forth by AISC or the barge's classifyingauthority.

j. Be equipped with suitable mooring cleats or equivalent to permit the barge to beadequately moored.

3.2 TOWING TUGS

Towing tug bollard pull shall be adequate to assure a minimum forward speed of oneknot when towing into a forty knot wind, a one knot current and an eight foot significantsea. The one knot current and eight foot significant sea may be disregarded for inlandtows. The bollard pull shall also be sufficient to maintain a minimum tow speed of fiveknots in calm environmental conditions. The last requirement may be waived for a wettow of the hull or Vessel depending on hull or Vessel shape.

3.3 SPECIAL TRANSPORT VESSELS

Special transport vessels which cannot be classified as cargo barges or tugs shall complywith the applicable requirements of this Technical Specification in order to be utilized forthe transport of Components.



FIGURE 2.2.1 TRANSPORT FORCES