MAP-01-011 HFI Technical Guide - Human Factors Integration ...

MAP-01-011 – HFI Technical Guide (STGP 11)DimensionHabitability FactorHFI Technical IssuesPhysical • Motion• Vibration• Noise• Atmosphere-Temperature, humidity, ventilation, pollutants• Lighting-visibility, readability, glare, adaptation, skin tone.• ClothingTable 13-1: Habitability Factors and Constituent Dimensions13.1.5 Ship Motion and SeakeepingPoor seakeeping performance in severe weather conditions can degrade thefighting capability of naval vessels, mainly due to the adverse effect the motion ofthe Ship has on crew performance. Therefore the adverse effects of ship motionon human performance need to be quantified, if possible, and minimised. Themain symptoms of human performance degradation are an increase in the timetaken to perform tasks, a reduction in output accuracy, and for physicallydemanding tasks a reduction in task safety.There are three categories to consider when evaluating the effects of motion onShip’s personnel:1. Motion Sickness – Motion sickness is generally associated with lowfrequency linear accelerations in the vertical axis, to which rolling andpitching contribute. Adaptation often occurs over 3-4 days unless motioncharacteristics change. Task performance may be degraded even whensymptoms of sickness are not visible and, in the worst case (when vomitingoccurs) task performance is reduced to zero. Excessive motion sicknessproblems will severely decrease the comfort of the crew, vessel habitability,and effectiveness of the Ship.2. Motion-Induced Interruptions (MII) – Ship’s motions can directly affectthe postural stability of personnel. Events known as motion-inducedinterruptions (MII) are particularly disruptive to short-term tasks that requirebalance and co-ordination. A model is available to assess the effects ofMII on the performance of non-seated tasks (refer to Institute of NavalMedicine (INM)).3. Motion-Induced Fatigue – Motion-induced fatigue is responsible for thefact that performing a physical task at sea is more fatiguing than carryingout the same task ashore. On smaller naval vessels, motion-inducedfatigue is probably due to the additional energy required to maintainpostural control. Fatigue and its effects are likely to accumulate duringextended periods at sea and factors such as work/rest schedules andsleep quality and quantity will be important.All of these effects can lead to degradation in performance of both physical andcognitive shipboard tasks. The categories of tasks whose performance are mostsensitive to ship motion need to be identified and the combined effects of themotion-induced symptoms assessed. The task descriptions for the platform willNov 2006 Page 13-6 Issue 4