Original sentence: Apart from that, any devices such as dredging-type crafts or small submarines equipped (e.with grab or suction devices) to capture submerged divers are either currently nonexistant or classified
Edited sentence: Apart from that, I have not come across in the real world of any such thing as a dredging-type craft or a small submarine equipped (e.with a grab or suction device) to capture submerged divers, but such a device may be possible