Human responses to noise and vibration aboard ships

Within the EU FP7 project SILENV, noise and vibration measurements were carried out on several ships. These objective measures were accompanied by subjective measures recorded through questionnaires. With this, we developed models describing the relationship between the levels of noise and vibration on board ships and subjective ratings on comfort of passengers and performance of crew. The various ordinal subjective ratings that were obtained were reduced through correlation, factor analyses and common sense. Rated annoyances were used to predict passenger discomfort, work quality impairments to predict crew performance. The relationship between dependent (subjective ratings) and independent variables (explanatory variables and noise/vibration levels) appeared to be non-linear. Models with good fitness and highly significant model parameters were obtained by binomial logistic regression. Ordinal subjective ratings were therefore transformed into dichotomous variables using the categories "a little" or less, and "moderately" and up (annoyed, work impaired). As such, the models predict the probability of feeling discomfort or work quality impairment on an individual basis or as a proportion of a population with a given demography. Besides level, age was predictive for noise annoyance too – the higher the age, the less annoyed – and gender for vibration annoyance – males being less susceptible to vibration than females. The models can be used to evaluate the effect of countermeasures intended to increase human comfort and performance and may serve to assess advisable levels of noise and vibration.