IPTI370 Design and Analysis of Floating Structures Introduction to Floater Types and Functions (Perryman)       

Introduction Key Requirements of Floaters Main Types of Floaters Floater Characteristics Functions of Deepwater Floaters Floater Project Requirements Classification

Basics of Hydrostatics and Stability (Halkyard)                      

Naval Architecture nomenclature How is Hydrostatics Applied - Examples Four Rules of Floating Platform Design Archimedes Principle Transverse Stability Example problem of Semi-Submersible Deck Load Capacity Effect of Partially Filled Tanks and Crane Operations Inclining Experiments Hydrostatic Curves Example Problem using hydrostatic curves Large Angle Restoring Moment How to Determine Righting Moment Curve Problem 3: Righting Moment Calculation Cross Curves of Stability for KZ Class Rules for Stability Watertight & Weathertight Integrity Stability Rules Applied to Different Platform Types Overturning Moment Curves – Wind Loads Example Spar Wind Area Damaged Stability Rules Compartmentation Criteria Software Available and Demonstration of Simple Program

Structural Design and Analysis (Halkyard)     

Hierarchy of Structural Elements Framing Design Process Rule Based Scantling Design and Structural Weight Estimating – Example Strength, Buckling and Fatigue Basics Global Analysis Process

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Loads and Load Mapping Semi/TLP/Spar Loading FPSO – Global Loads Rules vs. First Principle Approach

Global Design (Perryman) 

Check List for Global Design - Buoyancy = Weight plus Vertical Loads - Platform is stable (GM positive, meets rules) - Platform stays on location - Deck remains above the highest waves - Risers intact - Low motions - Water Depth - Environment - Add payload - Service Life

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General Global Design Process - Trial Size - Buoyancy Computational - Example: Buoyancy Calculation - Estimate Hull Weight - Outfitting Weight - Mooring Vertical Loads - Riser Vertical Loads - Variable Ballast - Example Problem - Other Criteria – Air Gap, etc. - Are Global Responses Acceptable?

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Configuration Freeze - General Arrangement Drawings - Hull Scantling Drawings - Weight Report - refined to an accuracy of at least ± 10%. - Mooring system has been sized - Global response and riser analysis will continue through the FEED process but should not alter the overall configuration. - Marine systems requirements

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Discussion Question

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Related Aspects of Global Design - Global Structural Analysis - Global Structural Analysis - Example - Critical Path for Global Design - Suction Piles for Spread Moorings - Model Testing - Marine Operations Manual

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Specific Platforms and Examples -

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SPAR Semi-submersible Tension Leg Platform FPSO

Review Questions

Mooring Design and Analysis (Halkyard)   

Definition of “Station-Keeping” Functional Requirements - Example Drilling Operations Production Offset Riser Limits

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Types of Station-Keeping Systems - Dynamic Positioning - Passive Mooring Systems - Catenary vs. Taut Mooring - Taut Mooring

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Example Problem: Taut Mooring (linear springs)

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Catenary Theory - Minimum Scope as Function of Tension (for no uplift on anchor) - Example Catenary Problem - Catenary Spreadsheet - Taut Mooring Solution (Spreadsheet) - Finite Element Approach - Finite Element Example

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Spread Mooring System Design and Analysis - Coordinate systems - Mooring Criteria – Recommended Practices - Combining Global Responses with Mooring Characteristics

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Mooring Line Components - Chain Types and Grades - Wire Rope Constructions - Synthetic Rope - Connectors - Chain Jacks & Fairleads - Mooring Winches (Wire Rope)

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Anchor Types

Global Responses/Hydrodynamics (Halkyard)    

The Importance of the Environment Sagging & Hogging in Waves Loads on Semis and TLPS Environments in the Design Basis -

Operational Seas Fatigue Bins Extreme Conditions Using Response Based Analysis

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Waves and Wave Theory - Airy Wave Theory - Higher Order Wave Theories - “Regular” vs. “Irregular” Waves - Wave Spectra

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Wind -

Wind Profile Wind Gusts – Short Term Wind Gust Spectra

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Currents - Storm-Driven Currents - Inertial Currents - Eddies - Cold Core Eddies

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Forces in waves - Radiation vs. Diffraction Forces - Added Mass (A) and Damping (B) Example - Example: WAMIT OUTPUT - Viscous and Inertial Forces - Wave Force on Slender Member d/λ < 5 - Froude Krylov Force - Diffraction Force on Segment of Cylinder - Morrison’s Equation

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Platform Motions - Equations of Motion - Computing Mass Properties: Mass Moments of Inertia - Mean, Slowly Varying and Wave Frequency Motions - Damping – Free Decay - Example: Solve for the natural frequency and amplitude of motion

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Steady State Responses - Reponses to Regular Waves: Response Amplitude Operators - Spectral Analysis - Example: Spar Motions in Waves

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2nd Order Forces Slowly Varying Force Newman’s Approximation Slow Drift Force on Vertical Cylinder Slow Drift: Frequency Domain Example: Extreme Value Combining Slow Drift and Wave Frequency Viscous Damping: Equivalent Linear Damping Wave Drift Damping Damping from Risers and Moorings Example: Wave Drift Damping in Irregular Seas Example: Heave Response of a Semi Time Domain Solutions Vortex Induced Motions Software Discussion

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Model Testing - Types of Model Tests - Selecting the Scale - Model Construction - Measurements and Data Analysis - Selected Model Basins

Construction and Installation (Perryman) 

Practical Aspects of Fabrication - Materials

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Example: Spar Hull Construction Steps Hull Dry Transport Heavy Transport Vessels Practical Aspects of Offshore Installation - Mooring Pre-Installation - Anchor and Mooring Installation Vessels

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Derrick Barges

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Example: Suction Pile Transport and Installation - Suction Pile Launch & Lowering - Wire Transportation

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Spar Hull Float Off from Dry Tow Vessel Truss Spar Wet Tow Truss Spar During Upending Truss Spar Upended Mooring Hookup Polyester Loadout Polyester Handling Onboard AHT Fixed Ballast Installation Topsides Lift Floatover Deck Installation, Example: Kikeh Safety - Actual Project Safety Incidents - How to Achieve a Safe Project

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TLP Construction and Installation Example: Marco Polo Project Discussion Question: What is the main difference between Spar and TLP hull construction? Semi-submersible Construction and Installation - Quayside Topsides Installation - Inclining Test-Wet Tow to Site

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FPSO Conversion - FPSO Hull Conversion Preparation - FPSO Conversion Scope of Work Example

Wrap Up Discussion

Design and Analysis of Floating Structures IPTI370 Updated July 2014

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