Escort tug design alternatives and a comparison of their hydrodynamic performance
Bibliographic record
Abstract
Escort tugs can generate forces for steering and braking a disabled tanker which are greater than the bollard pull delivered by the propulsion system. This is achieved by using a hull shape and appendages that can generate very high forces at yaw angles up to 45 degrees, combined with an azimuthing propulsion system to resist the resulting yaw moments generated from the hydrodynamic forces. This mode of operation is known as 'indirect steering' and results in a high degree of interaction between the flow around the hull and the flow due to the propellers. Model experiments are the most promising approach for studying these complex interactions, but there is very little model data published on the subject. Successful escort tug designs have resulted from different combinations of appendages and propulsion systems but there is no published data that compares the predicted performance of different alternatives. This paper attempts to fill this gap by presenting the hydrodynamic performance of three different combinations of hull shape, appendages and propulsion system, and uses the results to discuss the effectiveness of alternative design solutions for escort tugs with specified steering force requirements.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".