The Recreational Craft Directive (RCD) introduced a compulsory set of standards and guidelines for the build of new leisure boats since 6 June 1998. Compliant vessels carry a CE Mark on a mandatory plate. This European legislation applies to most leisure craft that measure between 2.5m-24m.
The RCD subsequently introduced a section regulating sound emissions but these only cover the noise made by the boat and its machinery and have no bearing on sound signalling requirements. Indeed the RCD has no specific requirements for horns, whistles or bells.
Read this explanation which has been offered by Jan Mayerhöfer, Policy Officer for the Recreational Craft Directive at the European Commission. It clarifies that all craft CE-marked under the RCD still have to comply with the IMO ColRegs requirements for marine sound signals.