This book concentrates on the mooring systems of semi-submersibles, but the procedures and equipment used can apply to other types of specialist vessels. It includes practical guidance on topics such as anchor types. The text is supported by detailed diagrams of concepts such as deployment theory, as well as graphical presentation of anchor holding capacity. Other topics detailed include mooring equipment, the problems associated with anchoring equipment and advice on operational safety.

Part 1 Anchor Theory and Practice
1.1 Catenary mooring system theory
1.2 Design of spread mooring systems
1.3 Oil industry anchors
1.4 Anchor types and behaviour
1.5 Method of operation HHP anchors
1.6 Predicting holding power
1.7 Frictional resistance of the anchor line
1.8 Soil description and drag anchor factors
1.9 Soil classification table
1.10 Improving anchor performance
1.11 Anchor cable catenary data and its uses
1.12 Running HHP anchors in very hard ground
1.13 Mooring calculations
1.14 Working tension/initial pretension and storm loads
1.15 Anchor running tables (chain moorings)
1.16 Minimum deployed length – test and working tensions

Part 2 Mooring Equipment
2.1 Anchors
2.2 Anchor line – wire and chain
2.3 Anchor rigging
2.4 Anchor chasers
2.5 Drop anchor rigging
2.6 Permanent chain chaser pennants
2.7 Anchor shackles tables and dimensions
2.8 Bulldog grip table
2.9 Attachment of anchor to anchor line
2.10 Pennant connection pigtails
2.11 Pennant lines
2.12 Pennants – use of pigtails and rigging
2.13 Open and closed spelter sockets
2.14 Pennant wire – standard lengths and coding
2.15 Anchor buoys
2.16 Clump weights

Part 3 Anchor Patterns
3.1 Anchor patterns

Part 4 Planning Mooring Operations
4.1 Basic planning steps
4.2 Planning questions to be answered
4.3 Mooring plan
4.4 Anchor handling vessels
4.5 Positioning systems
4.6 Rig move procedure
4.7 Site surveys
4.8 Approvals and permissions
4.9 Positioning systems – requirements and capabilities
4.10 Anchor handling vessel requirements - what type and how much power is needed?
4.11 Briefing and discussion with workboats
4.12 Basic rules of anchor work
4.13 Operational cautions – notes on good practice
4.14 Going onto location
4.15 Departure from location
4.16 Crew deployment and briefing
4.17 Anchor handling orders/advice and vocabulary
4.18 Positioning system checks – going onto location
4.19 Re-running, test tensioning and final positioning
4.20 Verifying mooring line position in tight locations
4.21 Equipment checks for anchoring machinery
4.22 The anchor handling basket
4.23 Check list for anchor handling
4.24 Anchor handling plan and procedure
4.25 Marine procedures

Part 5 Running and Retrieving Anchors
5.1 Running anchors – summary of operations
5.2 Running anchors – sequence of events
5.3 Retrieving anchors – permanent chain chaser systems
5.4 Retrieving anchors – buoyed systems
5.5 Passing pennant wires
5.6 Breaking chain out of sticky ground
5.7 Racking anchors

Part 6 Specialised Anchor Work
6.1 Introduction to specialist mooring operations
6.2 Two boat operations – laying and retrieving anchors
6.3 Mooring on smooth rock bottoms
6.4 Confined space short mooring – doubled chain
6.5 Interference mooring
6.6 Anchoring sequence
6.7 Anchoring sequence – running anchor through flare bridge
6.8 Support mooring operation
6.9 Support mooring
6.10 Jack-up positioning/mooring operations with interference/cross line problems
6.11 Mooring over obstructions without support buoys
6.12 Installation of single buoy moorings (SBMs)
6.13 Special moorings

Part 7 Mooring Problems – piggy backing, fishing and fouling
7.1 Piggy back anchor work
7.2 Fishing and grappling
7.3 Problems with anchoring equipment
7.4 Gypseywear
7.5 Windlass drive teeth damage and wear
7.6 Spurling pipe wear

Part 8 Pipelaying Barge Mooring Work
8.1 Plotting anchor movements
8.2 Pipeline crossing operations
8.3 Temporary buoys
8.4 Temporary pipeline crossing arrangements
8.5 Beach pull operations
8.6 Cautionary note – limits of weather working

Part 9 Heavy Lift Barge Operations

Part 10 Operational Safety
10.1 Risks on the anchor handling boat
10.2 Risks on the barge

Part 11 Positioning Systems

Part 12 Boat Selection and Capability

Part 13 Mooring System Management
13.1 Introduction
13.2 Daily routine
13.3 Moving the vessel within the anchor spread

Part 14 Anchor Winch Operation
14.1 General remarks
14.2 Basic operational precautions
14.3 Specialised barge winches
14.4 Emergency release
14.5 Electrically driven winches – features
14.6 Notes on mooring line length and tension devices
14.7 Operators’ instructions
14.8 Trouble shooting
14.9 Weekly anchor winch tests

Part 15 Anchor Line Inspection
15.1 Chain mooring line damage types – symptoms, causes and remedies
15.2 Visual examination of chain cable
15.3 Detailed specialist examination
15.4 The use of replacement anchor chain studs (gem stud type)
15.5 Mechanical properties of chain grade steel
15.6 Procedure for chain inspection – notes
15.7 Wire mooring line inspection and maintenance guidelines

Part 16 Anchor Handling Reports

Part 17 Adverse Weather and Working Limits Data

Michael Hancox

Captain Michael Hancox is a Marine Consultant and former Director of Hancox Marine Services Limited.

Witherbys

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Witherbys staff have significant expertise in the fields of navigation and hazardous cargoes as well as in the presentation of complex subjects in a graphic and easy to understand manner.