Improving crashworthiness calculations for safe containment of hazardous fuels

In order to reduce its environmental footprint the maritime community wants to replace fossil fuels by alternative energy carriers such as methanol, hydrogen and ammonia. In the recent past, these substances were not allowed on board as fuels, because of their hazardous nature. Currently however, regulations are being developed within the international maritime organisation’s (IMO) regulatory community, allowing these substances. This permission is subject to additional requirements, intended to attain a safety equivalent to conventional fuels such as heavy fuel oil (HFO) and marine gas oils (MGO). A major issue, although sometimes not yet fully recognized, is positioning of tanks for alternative fuels, because of prescribed safety distances related to collision protection and poor volumetric energy densities, posing severe design restrictions. This paper outlines how crashworthiness can be exploited to bring some relief in this matter. The outline is largely based on the experience with designing for crashworthiness in inland water way tanker shipping. Based on this experience, the paper proposes aspects of further research that should lead to improvements upon the current crash calculation practice in the maritime domain.