Computer Based Systems (CBS) and Integrated Bridge Systems (IBS) are being introduced. They provide enhanced navigation capabilities and promote ship safety. However, they are highly complex and are becoming the primary source of data/information used to navigate ships. CBS issues have arisen that challenge current safety assurance and certification practices. This paper explores the potential contribution of System Safety Engineering including technical, operational management and crew capability contributions to CBS/IBS safety. A six step roadmap for the production of best practice guidance for the safe development and operation of such systems is presented.