I've noticed that when I turn using the mouse it only partially turns, even tho I have not returned the mouse back to central position. I've tried using the keyboard for turning but it's too fast.

Is it possible to have the mouse continually turn until it's brought back to original position?

Sounds like the wrong tool for the job.

VO's got two mouse steering modes. Mouselook, and non-mouselook. Neither one works like the way you're describing.

You can get that sort of behavior with a joystick or gamepad though.

I have it set as "keyboard - mouse" under the 'control' settings.
But as I attempt to catch the ship behind me the mouse will rotate my ship but only part way ,
I have to repeat the motion to eventually face the enemy ship.
needless to say, I'm not having much success in fights.

I wondered if this was an issue with Linux (Ubuntu 13.10) or a setting I could adjust in VO.

Nope, mouse behavior is the same across platforms. The only current options are the ones abortretryfail listed. In case you aren't familiar with them, with mouselook off, your view and your ship's orientation are solidly linked, and mouse movements directly control ship movements. With mouselook on, your view and ship orientation are more decoupled; you can look around freely as fast as you wish, and the ship will attempt to catch up.

Mouselook can be toggled on the fly by pressing the semicolon key, and has nothing to do with the "keyboard - mouse" setting in the controls.

I have also wished at times for a control scheme like the one you described, so I just proposed it in the suggestions forum.
http://www.vendetta-online.com/x/msgboard/3/28403