For adventure purposes I'm saying that the engine can be used for direct steam rocket propulsion to achieve 25-30 KPH underwater (it can do more than this but the propellers and fins are used for steering and attitude control and fairly ineffective at high speed), cruising speed (propellers only) is more like 10-15 KPH. The hull is designed for vacuum as well as pressure, and the engine is powerful enough to take it into orbit around Ceres in an emergency, but it lacks the steering engines of a real spacecraft - there's a little attitude control via compressed air jets but capacity is very limited, and steering isn't accurate enough for a safe landing, even on Ceres. You'd basically do this as a last resort, if you couldn't get back to your base, and someone would have to rescue you. The hull is rated to 4000 M on Earth, so should be good to about 120 Km inside Ceres.
No built-in weapons - it's intended for peaceful scientific exploration.
Later In answer to the points raised I've had another go - this one fixes the rear concavity and makes the ports smaller, and fixes a problem affecting compatibility with older versions of Acrobat, also somehow makes the file 250k smaller which is always useful!
But there are still only two pressure suits, and ordinary space suits are NOT diving suits. I'm a stinker, aren't I...