The Five-Factor Perceived Shared Mental Model Scale: A Consolidation of Items Across the Contemporary Literature

Literature on Shared Mental Models (SMMs) has been burgeoning in recent years and this has provided increasingly detailed insight and evidence into the importance of SMMs within specific contexts. However, because past research predominantly focused on SMM structure as measured by diverse, context-dependent measures, a consolidated multi-dimensional measure of perceived SMMs that can be used across diverse team contexts is currently lacking. Furthermore, different conceptualizations of the dimensionality of SMMs exist, which further impedes the comparison between studies. These key limitations might hinder future development in the SMM literature. We argue that the field of SMMs has now matured enough that it is possible to take a deductive approach and evaluate the prior studies in order to refine the key SMMs dimensions, operationalizations, and measurement. Hence, we take a three-stage approach to consolidate existing literature scale-based measures of SMMs, using four samples. Ultimately, this leads to a 20-item five-dimensional scale (i.e., equipment, execution, interaction, composition, and temporal SMMs) – the Five Factor Perceived Shared Mental Model Scale (5-PSMMS). Our scale provides scholars with a tool which enables the measurement, and comparison, of SMMs across diverse team contexts. It offers practitioners the option to more straightforwardly assess perceived SMMs in their teams, allowing the identification of challenges in their teams and facilitating the design of appropriate interventions.

PRESSURE DISTRIBUTION DUE TO STERN TAB DEFLECTION AT MODEL SCALE

Trim tabs form an important part of motion control systems on high-speed watercraft. By altering the pitch angle, significant improvements in propulsion efficiency can be achieved by reducing overall resistance. For a ship in heavy seas, trim tabs can also be used to reduce structural loads by changing the vessel orientation in response to encountered waves. In this study, trials have been conducted in the University of Tasmania hydraulics laboratory using a closed- circuit water tunnel to measure model scale trim tab forces. The model scale system replicates the stern tabs on the full- scale INCAT Tasmania 112 m high-speed wave-piercer catamaran. The model was designed for total lift force measurement and pressure tappings allowed for pressures to be measured at fixed locations on the underside of the hull and tab. This investigation examines the pressures at various flow velocities and tab deflection angles for the case of horizontal vessel trim. A simplified two-dimensional CFD model of the hull and tab has also been analysed using ANSYS CFX software. The results of model tests and CFD indicate that the maximum pressure occurs in the vicinity of the tab hinge and that the pressure distribution is long-tailed in the direction forward of the hinge. This accounts for the location of the resultant lift force, which is found to act forward of the tab hinge.

PERFORMANCE PREDICTION OF A 112M WAVE-PIERCING CATAMARAN

The prediction of power required to propel a high-speed catamaran involves the hydrodynamic interactions between the hull surface and the surrounding fluid that may be difficult to compute numerically. In this study model-scale experiments are used as a basis for comparison to full-scale sea trials data measured on a 112m Incat wave-piercing catamaran to predict the full-scale powering requirements from model-scale testing. By completing water jet shaft power measurements on an Incat vessel during sea trials, comparison of these results was made to model-scale test results to provide good correlation. The work demonstrates that the International Towing Tank Conference (ITTC) extrapolation techniques used provide a good basis for extrapolating the data from model-scale to full-scale to predict the power requirements for the full-scale catamaran vessel operating at high Froude Number with water jet propulsion. This provides a useful tool for future designers and researchers for determining the power requirements of a catamaran vessel through model tests.

NON-DIMENSIONALISATION OF LATERAL DISTANCES BETWEEN VESSELS OF DISSIMILAR SIZES FOR INTERACTION EFFECT STUDIES

To date, most of the hydrodynamic interaction studies between a tug and a ship during ship assist manoeuvers have been carried out using model scale investigations. It is however difficult to establish how well results from these studies represent full scale interaction behaviour. This is further exacerbated by the lack of proven methodologies to non- dimensionalise the relative distances between the two vessels, enabling the comparison of model and full scale interaction effect data, as well as between vessels of dissimilar size ratios. This study investigates a suitable correlation technique to non-dimensionalise the lateral distance between vessels of dissimilar sizes, and a scaling option for interaction effect studies. It focuses on the interaction effects on a tug operating around the forward shoulder of a tanker at different lateral distances during ship assist operations. The findings and the non-dimensioning method presented in this paper enable the interaction effects determined for a given ship-to-tug ratio to be used to predict the safe operational distances for other ship-to-tug ratios.