Reconstructing ships so that they have a double hull can protect them from serious damage in the roughly 20 percent of shipping accidents that unavoidably result from severe weather conditions  Avoidable human error, however, causes about 80 percent of shipping accidents
It would ttherefore be far more cost-effective to reduce damage to ships by retraining sailors than by reconstructing ships
One should always try to reduce the severity of the damage caused by each individual accident rather than try to minimize the number of accidents.