The Thornback Submarine is a Cobra diesel-electric stealth craft, with the shape of a ray (cartilaginous fish). It has a displacement of 2,900 tons when submerged and 2,100 tons when on the surface. The submarine has a maximum submerged speed of 32 knots and a maximum surface speed of 15 knots, with a maximum range of 6,000 nautical miles.
- G.I. Joe: Field Manual Vol 2