Motion-induced interruptions aboard ship: Model development and application to ship design

Abstract

The most severe direct motion induced effect on the ability of an individual to work in a moving environment probably occurs in gross body tasks requiring balance and co-ordination, be it the crew trying to undertake their task effectively or the passenger trying to walk around the vessel. During rough weather working in the ship becomes more difficult and even the most experienced sailor will experience events where they must stop their activity, be it a specific task or merely standing, and hold on to some suitable point to minimise the risk of injury; these events are called Motion-induced interruptions (MIIs). MIIs were recorded during the performance of a series of tasks on board a ship at sea in rough weather. The tasks were: standing facing aft, walking athwartships, a simulated weapon loading task, standing facing athwartships and a simulated fire-fighting task. Complex mathematical models of postural stability exist but currently lack the fidelity to accurately predict MIIs. This paper presents data from an empirical study in which MIIs experienced by subjects on a ship at sea were logged by an observer. Measurements of lateral and vertical acceleration of the deck immediately prior to the MII were made and thresholds of acceleration for undertaking task were determined. These so called tipping coefficients are presented for use with predictive tools in ship design.

The Effect of Wave Motion Intensities on Performance in a Simulated Search and Rescue Task and the Concurrent Demands of Maintaining Balance

“…Our finding that the SAR task performance decreased in the high-motion environment is consistent with prior work involving standardized physical tasks, including visuomotor tracking tasks, speed of lifting and lowering loads, speed of trackball manipulation, pen-and-paper tracing tasks, and computer tracing tasks (Crossland & Lloyd, 1993; Duncan et al, 2012; Pearcey et al, 2015; Wertheim, 1998). Our results are also consistent with previous research that demonstrated that vigilance performance in rough seas was reduced relative to the same participants completing the same tasks in mild seas (Yu, Yank, Katsumata et al, 2010, Yu, Yank, Villard et al, 2010).…”

“…Reactive stepping may distract from the SAR task. In the maritime engineering community, reactive steps are characterized as motion-induced interruptions (MIIs), and have been shown to increase the risk of human factors errors (Crossland et al, 2007; Graham, 1990; Lewis & Griffin, 1997). We recently demonstrated that detriments in the performance of a secondary task in maritime moving environments may be related to the increased cognitive and attentional demands required to maintain postural control (Duncan, Hickey, Byrne, 2018).…”

“…Maintaining balance in wave-induced moving environments is challenging, and often requires stepping responses to remain upright and avoid falls (Crossland & Lloyd, 1993; Duncan, 2013; Duncan et al, 2013; Duncan et al, 2014a). Humans can maintain balance during small perturbations without consciously focusing on external cues (Riley et al, 2003); however, more demanding situations may require additional attentional strategies (Andersson et al, 2002; Woollacott & Shumway-Cook, 2002).…”

Small Boat Recovery Task Performance in a Moving Environment

“…Of note, we did not observe any slips, slides, loss of balance, or temporary task abandonment indicative of a conventional MII (Baitis et al, 1984;Crossland & Lloyd, 1993;Crossland & Rich, 1998;Graham, 1990;Graham et al, 1992). We interpret the delay in attempting to connect the hook in higher sea states to be more characteristic of a motion-induced correction (Duncan et al, 2013;Matsangas & McCauley, 2013).…”

“…From a performance perspective, environmental motion during the small boat recovery task can lead to "motion induced interruptions -MIIs." Introduced in the 1980s, an MII was defined as an incident in which a standing individual slips, slides, or loses his/her balance because of environmental motion, or temporarily pauses or abandons performing his/her task to maintain or regain balance (Baitis et al, 1984;Crossland & Lloyd, 1993;Crossland & Rich, 1998;Graham, 1990;Graham et al, 1992). Later, the definition of an MII was expanded to include all task interruptions caused by motion (McCauley et al, 2005), and refined models were developed to assess human postural equilibrium in complex motion environments (Langlois, 2010;Wedge & Langlois, 2003).…”