5. The Six Degrees of Freedom
P I T C H
R O L L
H E A V E
SURGE SWAY YAW
Measured by means of position reference systems Measured by means of gyro
PITCH ROLL HEAVE
Measured by means of vertical reference sensor. VRS, VRU, MRU
Controlled by means of thrusters
8. DP definitions - IMO
IMO
DP-vessel:
Dynamically positioned vessel (DP-vessel) means a unit or a
vessel, which automatically maintains its position, (fixed location
or predetermined track), exclusively by means of thruster force.
IMO
DP-System:
Dynamic Positioning system (DP-system) means the complete
installation necessary for dynamically positioning a vessel comprising
the following sub-systems:
DP-control system
Thruster system and
Power system
9. What is a Dynamic Positioning System
IMO (International Maritime Organization)
“the complete installation necessary for dynamically
positioning a vessel comprising of the following sub-systems”
10. DP Definitions - IMO
DP Control System
DP Control System means all control components and systems,
hardware and software necessary to dynamically position the vessel.
The DP control system consists of computer and joystick systems,
sensor system, display system (operator panels), position-reference
systems and associated cabling and cable routing.
11. DP System - IMO
• Power system
• Thruster system
• DP Control system, with:
- Computers
- Joystick systems
- Sensors
- Position Reference-systems
- Display system
- Operator panels
- Cabling and cable routing
12. Main Purpose of a DP system
• Provide single Joystick control of all thrusters
• Maintain position and heading of the vessel by automatic
control of thrusters
• Change position and heading by automatic control of
thrusters
14. DP Main Modes
• Standby mode
• Joystick mode
• Auto Position mode
15. Standby Mode
• Standby Mode is a waiting and reset mode in which the system is in
a high state of readiness, but in which no vessel control commands
can be made
16. Joystick Mode
Main Functions
• Provide single Joystick control of all thrusters
• Possibility for Environmental Force Compensation
• Possibility for Mixed Joystick/Auto mode
17. Auto Position Mode
Main Functions
• Present Position
• Change Position
• Present Heading
• Change Heading
41. Advantages / Disadvantages of DP
Advantages
No mooring lines / anchors
No tugs required
Quick and easy setting up
Can shift quickly
Rapid response to weather
Various modes of operation
Ability to work in any depth
Task completion more quickly
No damage to sea bed
Disadvantages
Equipment failure
Higher fuel consumption
May “Run Off”
Problems in shallow waters
Position Reference Systems
Redundancy for most tasks
Competent staff
Higher day rates