All electronic products including LED floodlights, LED navigation lights and searchlights emit electromagnetic noise, which can cause problems. The question is only, if the level of noise is above what is acceptable for your application?

This video will give you a very simple explanation of both conducted and radiated electromagnetic emissions. For marine applications (and many others) the solution is to look for MIL-STD-461F or IEC60945 or IACS E10.1 No.19, all concerning Radiated Emission, when it comes to Electromagnetic Interference (EMI) and Electromagnetic Compatibility (EMC).