The correct answer is B. Communications involving safety of life at sea must always be logged, even if the compulsory vessel was not directly involved in such communications. The GMDSS (Global Maritime Distress and Safety System) regulations require that all communications related to the safety of life at sea be properly documented in the vessel's radio log. This is a critical requirement to ensure effective communication and coordination during emergencies. Option B is therefore false, as it suggests that such communications do not have to be logged. The other options are correct - GMDSS Radio Operators can perform maintenance on the equipment under the supervision of a licensed GMDSS Radio Maintainer (A), and each compulsory vessel must carry at least two licensed GMDSS Radio Operators at all times while at sea (C and D).