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
Damage from accidents can be reduced more cost-effectively by reducing the likelihood of accidents than by mitigating their effects.