DP Stationkeeping Accuracy - A Calcuation Approach, Integration in - - PowerPoint PPT Presentation

▶
dp stationkeeping accuracy a calcuation approach
SMART_READER_LITE
LIVE PREVIEW

DP Stationkeeping Accuracy - A Calcuation Approach, Integration in - - PowerPoint PPT Presentation

Jan 18, 2023 284 likes •498 views

DYNAMIC POSITIONING CONFERENCE OCTOBER 911, 2017 PERFORMANCE DP Stationkeeping Accuracy - A Calcuation Approach, Integration in DP Plots and Results of a Case Study Hans Cozijn and Jorrit-Jan Serraris Marin DP STATIONKEEPING ACCURACY A

slide-1
SLIDE 1

DYNAMIC POSITIONING CONFERENCE

OCTOBER 9‐11, 2017

PERFORMANCE

DP Stationkeeping Accuracy - A Calcuation Approach, Integration in DP Plots and Results of a Case Study

Hans Cozijn and Jorrit-Jan Serraris Marin

slide-2
SLIDE 2

DP STATIONKEEPING ACCURACY

A CALCULATION APPROACH, INTEGRATION IN DP PLOTS AND RESULTS OF A CASE STUDY

Hans Cozijn and Jorrit-Jan Serraris

slide-3
SLIDE 3

2

PRESENTATION OUTLINE

  • Study Objective
  • Available Analysis Methods
  • Proposed Calculation Approach
  • Concluding Remarks
slide-4
SLIDE 4

3

STUDY OBJECTIVE

Propose a calculation method that combines the advantages

  • f time-domain simulations and static DP capability calculations.
  • Results give an immediate impression
  • f the vessel DP capability in a single diagram
  • Results include information on stationkeeping accuracy

and other operational parameters.

slide-5
SLIDE 5

4

PRESENTATION OUTLINE

  • Background
  • Available Analysis Methods
  • Proposed Calculation Approach
  • Concluding Remarks
slide-6
SLIDE 6

5

DP STATIONKEEPING ANALYSIS METHODS

  • Static Calculations
  • Time-domain Simulations
  • DP Model Tests
  • Sea Trials

+ Simple and fast + Easy to compare thruster types, sizes and positions + Easy to analyze effects

  • f thruster failure
  • Mean loads only
  • No stationkeeping accuracy
  • Difficult to compare calculations

from different sources

slide-7
SLIDE 7

6

DP STATIONKEEPING ANALYSIS METHODS

  • Static Calculations
  • Time-domain Simulations
  • DP Model Tests
  • Sea Trials

+ Complete simulation model

  • f DP vessel in wind, waves, current

+ Dynamic effects are included + Determine stationkeeping accuracy + Optimize filter and control settings + Investigate transient response

  • More input data required
  • Need to run many simulation cases
  • Run sufficiently long simulations
  • Post-processing of results
slide-8
SLIDE 8

7

DP STATIONKEEPING ANALYSIS METHODS

  • Static Calculations
  • Time-domain Simulations
  • DP Model Tests
  • Sea Trials

+ Complete representation

  • f DP vessel in wind, waves, current

+ All physics are included (possible un-expected behavior) + Safely investigate limiting cases + Optimize filter and control settings + Generic or commercial DP system

  • Costs
  • Risk of scale effects
slide-9
SLIDE 9

8

DP STATIONKEEPING ANALYSIS METHODS

  • Static Calculations
  • Time-domain Simulations
  • DP Model Tests
  • Sea Trials

+ "The Real Thing" + No simplifications or assumptions

  • Costs
  • Vessel availability
  • No control over environment
  • Too late for design changes

Photo : Havyard Design & Solutions AS

slide-10
SLIDE 10

9

PRESENTATION OUTLINE

  • Background
  • Available Analysis Methods
  • Proposed Calculation Approach
  • Concluding Remarks
slide-11
SLIDE 11

10

PROPOSED CALCULATION METHOD

  • Time-domain Simulation Model
  • Execute Simulations
  • Current; variation Vc, direction
  • Waves; variation Hs, Tp, direction (IMCA)
  • Wind; linked to waves (IMCA, ERN)
  • Swell; variation Hs, Tp, direction
  • Several 1,000 individual simulations
  • Store Results in Database
  • Apply Operational Criteria
slide-12
SLIDE 12

11

STEP-BY-STEP APPROACH

  • Time-domain simulation model
  • Execute simulations
  • Store results in data base
  • Apply operational criteria
slide-13
SLIDE 13

12

STEP-BY-STEP APPROACH

  • Time-domain simulation model
  • Execute simulations
  • Store results in data base
  • Apply operational criteria

 "CONDOR" batch simulations  250+ desktop PCs (in network)  20,000 or more cases  +/- 1 night, or 1 weekend

slide-14
SLIDE 14

13

STEP-BY-STEP APPROACH

  • Time-domain simulation model
  • Execute simulations
  • Store results in database
  • Apply operational criteria
slide-15
SLIDE 15

14

STEP-BY-STEP APPROACH

  • Time-domain simulation model
  • Execute simulations
  • Store results in data base
  • Apply operational criteria
slide-16
SLIDE 16

15

EXAMPLE - ACCESS SYSTEM MOTIONS

Gangway Stroke 5 m Gangway Stroke 7 m Gangway Stroke 9 m

Motions Exceeding Criteria; Gangway placed Midship and at Stern

slide-17
SLIDE 17

16

ADVANTAGES AND LIMITATIONS

  • Advantages
  • Evaluation of stationkeeping capacity and accuracy,

as well as other operational criteria (motions, accelerations)

  • Presentation of results in familiar polar plots
  • Set of operational criteria can be up-dated,

without the need to re-calculate

  • Limitations
  • More detailed input data required, compared to static calculations
  • Computational effort
slide-18
SLIDE 18

17

PRESENTATION OUTLINE

  • Background
  • Available Analysis Methods
  • Proposed Calculation Approach
  • Concluding Remarks
slide-19
SLIDE 19

18

SUMMARY REMARKS

  • Different Methods Exist to Evaluate DP Capability
  • Static
  • Time-domain
  • Model tests
  • Sea trials
  • Time-domain Simulation Based Calculation Method is Proposed
  • Presentation of results similar to static calculations
  • Benefits of a time-domain simulation approach
  • Evaluation of multiple operational criteria
slide-20
SLIDE 20

THANK YOU !

Hans Cozijn Senior Project Manager Offshore