The Radio Navigational Aids are publications utilized by mariners looking for details of radio stations that broadcast helpful information and provide services. Published annually, Pub 117 has a detailed list of services, carefully arranged into practical chapters. Many services will help seafarers in an emergency and include navigational warnings, medical advice, or emergency and safety guidelines.
Publication 117 provides radio stations such as the Global Maritime Distress Safety System. There are also detailed chapters that describe the AMVER system procedures, including communication requirements and emergency procedures to be followed in times of crisis. Pub 117 is available in a printed form and can also be found online in its entirety.