The FLISH is an unofficial pin that cryptologic direct support (DIRSUP) officers and enlisted deployers historically wore on their belt buckles or command ball caps signifying they deploy on submarines, aircraft or surface ships. 

Uniquely Naval Security Group (NSG), the designer took specific features from the submarine warfare pin, aircrew wings pin and the surface warfare pin and combined them into one pin.  The FLISH can also be found on several NSG command plaques associated with DIRSUP.

But what is the origin of the pin that so many DIRSUPers proudly displayed over the years?

According to Guy Thomas CDR (Ret.), he first saw the pin in 1970 or 1971 after returning from DIRSUP operations off Vietnam.  It was on a belt buckle worn by a newly arrived LT.

At that time, Thomas was told the meaning of the pin and that it came from NSGD Yokosuka, where it had originally been designed for the Technical Guidance Unit (TGU) riders, but the DIRSUP deployers at NSGA Kami Seya adopted it with the full support of their CO, CAPT (later RADM) Pat March.

When Thomas arrived at NSGA Misawa in January, 1972 the pin was everywhere and he asked who came up with the design.  He was told it was a CTTSN Parker at NSGD Yokosuka in 1969.

Can anyone confirm this?