- Solid colored t-shirts are 100% combed ringspun cotton, however, heathered colors could contain a cotton/polyester blend
- Preshrunk to minimize shrinkage
- Double-needle sleeve and bottom hems
On October 1, 1998, Sailors serving as Ocean System Technicians were merged into the Sonar Technician rating. us navy e7 ocean systems technician (ot) blue rating badge The fact that sound travels quite well under water—and faster than it does through the air—was one of the reasons that sonar (SOund Navigation And Ranging) was developed as a submarine detection device. On November 26, 1969, the Secretary of Navy approved the establishment of the Ocean Systems Technician rating (OT).