In recent years electromagnetic interference has become an increasing problem on merchant ships. This is due mainly to the increases in the power of shipboard radar and telecommunication equipment and increases in the size and complexity of ships electrical installations. At the same time the amount of electronic equipment has increased. It is anticipated that these trends will continue into the future.

Unlike naval vessels, merchant ships are not constructed at present with a view to the prevention of electromagnetic interference and problems are dealt with on an ad-hoc basis as they occur. It is unlikely that rigorous naval installation standards will ever be applied to merchant ships, however for the reasons given above it is becoming increasingly important that merchant shipbuilders have a fundamental understanding of the causes and effects of electromagnetic interference and of installation techniques and practices which will minimise the likelihood of significant problems occurring in future.

There is also a need for shipyard personnel to have access to a reference book covering the international standards and legislation covering future buildings. This will be enhanced by further guidance covering the basic terminology of electromagnetic interference.

This guidebook has been written with the above factors in mind. It is intended as a working document to be used by shipyard design and installation personnel.