General Dynamics Electric Boat of Groton, Conn., a wholly owned subsidiary of General Dynamics, has received a $32.9 million contract modification by the US Navy to procure three backup photonic masts for Virginia-class submarines. The masts – nonhull-penetrating imaging devices that do not extend physically into the control room – have replaced traditional periscopes in the submarines. Information is digitally recorded by cameras in the mast, transmitted through fiber optics into the ship and processed with onboard image processors. Each mast has a high-definition TV digital color camera, an infrared camera and a laser rangefinder.