What is the Shellback app? Shellback, formerly known as eDivo, is a free mobile app developed to support US Naval Surface Force (SURFOR) personnel in an easy-to-access offline environment. What is a Shellback? In naval tradition, a Shellback is a nickname for a Sailor who has crossed the Equator and thus transitioned from a novice Sailor, or Pollywog, to an experienced Sailor. Why do I need Shellback? Shellback provides Sailors the ability to download key SURFOR information on their own po