Basic

Question 1

What is Consequence analysis?

Answer 1

• A software function by the DP system.

Question 2

Why is consequence analysis used

Answer 2

-To assess the ability of a vessel to maintain position after a given failure.

Question 3

Who uses consequence analysis?

Answer 3

• DP Class 2 and 3 vessels.
• It is required to comply with class regulations.

Question 4

What is the feed forward function?

Answer 4

-Wind sensors directly sends measurements to the thruster controller.
-Allows fast reaction to rapid changes in wind strength and direction.

Question 5

What is fan beam?

Answer 5

-Laser positioning system (Range - Bearing).
-Outputs range. And relative bearing to the DP.
-Local positioning-reference system.

Question 6

What are the main components of a fan beam system.

Answer 6

-Laser Sensor.
-Monitor.
-LED Keypad.
-Processor.

Question 7

What are the advantages of a fan beam system?

Answer 7

-High accuracy when distance is short.
-Easy to install.
-Passive target and requires no support when installed.

Question 8

What are the disadvantages of a fan beam system?

Answer 8

-Inoperative when sun shining directly into the lenses.
-Lenses can be affected by consideration, rain and salt spray.
-Vulnerable to fog, snow and heavy rain.
-May be confused by bright lights/reflective items near the target.

Question 9

What is CyScan?

Answer 9

-Laser positioning system (Range - Bearing).
-Outputs range and reflective bearing to the DP.
-Local position-reference system.

Question 10

What are the Main components of CyScan?

Answer 10

-Laser Sensor.
-Power Supply.
-PC Console/Monitor

Question 11

What are the advantages of CyScan?

Answer 11

-High accuracy when distance is short.
-Easy to install.
-Passive target(s) and requires no support when installed.
-Intelligent algorithms built in to avoid false targets.
-Auto-levelling: Compensating for pitch/roll.

Question 12

What are the disadvantages of CyScan?

Answer 12

-Vulnerable to sun shining directly into the lenses.
-Lenses can be affected by condensation, rain and salt spray.
-Vulnerable to fog, snow and heavy rain.
-Rotor vulnerable to
Ice build up between rotor and gearbox cover.

Question 13

What is HPR?

Answer 13

• Hydrostatic, Position, Reference

Question 14

What is HiPAP

Answer 14

-High, Precision, Acoustic, Positioning

Question 15

What is the Purpose of HRP & HiPAP?

Answer 15

-A HPR/HiPAP system positions a vessel/rig relative to transponder, based on the principle of sound in water.

Question 16

What is SSBL?

Answer 16

-Super Short Base Line.

Question 17

What is SBL?

Answer 17

Short, Base, Line

Question 18

What is LBL?

Answer 18

Long, Base, Line

Question 19

What are the advantages to SSBL?

Answer 19

-Only requires one transponder/responder.
-Quick to do, only needs calibrated once.
-Easy to use and train people.
-Most vessels have one fitted.

Question 20

What are the disadvantages of SSBL?

Answer 20

-Requires VRU and Gyro - deep water high accuracy is expensive.
-Position accuracy degrades with increasing water depth.
-Limited on ranges approximately 2.5-4km slant range.

Question 21

What are the advantages to LBL?

Answer 21

-High positioning accuracy, better than 1m in 1500m depth.
-Position accuracy is independent of Depth.
-Vessel motion compensation not necessary for the LBL calculation.

Question 22

What are the disadvantages to LBL?

Answer 22

-Time-consuming transponder deployment.
-Calibration after deployment.
-Complicated operating procedures.
-Position update rate not as quick as SSBL.

Question 23

What are the advantages of a Taut Wire system?

Answer 23

-Accurate.
-Not dependent upon third parties.
-Easily deployed and re-deployed.

Question 24

What are the disadvantages of a Taut Wire system?

Answer 24

-Wire may bend in strong tide.
-Less accuracy in deep water.
-Limited operational area in shallow water.
-Limitation in use in areas with equipment at seabed.
-The risk of dragging the weight.