I think this is the last piece from the Terror from the Deep book that I'll post. There are a lot of good illustrations in there but I shouldn't post the entire book
This is the Barracuda submersible fighter used by Triton. Much like the Omega alien tech fighter this uses an anti-gravity drive as it's main source of propulsion. It's capable of flight in air like a conventional fighter, but is also designed to dive and fighter under water. It's armed with 2 large rail guns, 4 dart rifles mounted in turrets, and torpedos.