Innovative ship design concepts sometimes require technical and functional solutions which may conflict with the prescriptive requirements implicit in the current rules. For those cases, a number of provisions have been made in SOLAS to allow the development, evaluation and approval of such solutions, referred to as Alternative arrangements.

SafetyatSea has undertaken alternative design and arrangement studies in relation to life-safety appliances, means of escape routes, damage stability and fire safety for ropax and cruise vessels.

Alternative design & Arrangements

Alternative design and arrangements means measures which deviate from the prescriptive requirement(s) of SOLAS, but are suitable to satisfy the intent of those requirements. The term includes a wide range of measures, including alternative shipboard structures and systems based on novel or unique designs, as well as traditional shipboard structures and systems that are installed in alternative arrangements or configurations.

Since 1974, more than 100 approved alternative arrangements have been submitted to the International Maritime Organisation. The majority of these cases relate to provisions in Chapter II-1, II-2 and III of the SOLAS convention.

Safety equivalence

Safety equivalence studies may be required to demonstrate that an alternative design arrangement is at least as safe as an arrangement which complies with the prescriptive rules. Safety equivalence studies involve qualitative as well as quantitative assessments supported by necessary engineering calculations and follow a specific workflow described in guidelines and recommendations developed by the IMO (link to home > publications / other information).

Further information

Luis Guarin (l.guarin@safety-at-sea.co.uk)