Numerical Simulation of Ship Maneuverability in Wind and Current, With Escort Tugs
Bibliographic record
Abstract
A number of recent large-ship accidents have compelled naval architects and engineers to advance the research on ship maneuverability and the prediction of ship response in the ocean environment. In the meantime, new maneuverability standards have been developed and the International Maritime Organization (IMO) has also proposed one such standard. This standard provides four ship-maneuvering performance criteria, and its latest version is dated December 2002. Simulation technology, in particular the simulation of ship maneuvering, has advanced considerably in recent years with the advent of computers. Computer programs using either numerically computed or experimentally determined hydrodynamics coefficients have allowed an accurate simulation of ship maneuverability for different types of vessels. Relatively good agreement has been reported by various researchers between simulated results and those obtained from full-scale ship trials. It seems that simulation can now identify acceptable ship maneuvering performance in calm seas. However, the effects of wind and current and escort tug assistance have not been that well studied and reported, and they are always important factors for ship maneuvering especially in restricted waters. The numerical simulation program presented in this paper (UBCManeuver) has been validated using data on the Esso Osaka 278,000 DWT tanker, a ship well tested for regular maneuvering tests. UBCManeuver is able to identify IMO class and non-IMO class ships according to the most recent IMO standards for ship maneuverability. A good agreement was obtained between simulation and the sea trials reported for Esso Osaka. After the validation of the code, the course-keeping abilities of this ship in restricted waters were studied in calm seas and under wind and current conditions. The effect of escort tugs on such an operation has also been quantified and Esso Osaka's maneuvering performance around Vancouver harbor simulated. The limits of current and wind strengths for "successful" operation with and without escort tugs have then been established. In addition, the effectiveness of multiple tug assistance in different positions is discussed in some detail.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".