An extra boarding crew would provide a +10 bonus to your boarding actions per crew, and I'd say your ship can fit three boarding crews aboard.  (one in the cargo bay, one in the luxury quarters, and one in the xeno habitat.  If your cargo bay were completely empty, you could add a fourth crew.)<br/><br/>Boarding crews provide their bonus until they lose a hit and run or boarding action, at which point they're too dead or disorganized to be useful.<br/><br/>Frigates carry 1 boarding crew, cruisers carry 2 boarding crews, and ships with barracks carry an additional 2 crews.  Orbital Defense platforms have 1 crew each, and Attica Station had 3 crews when it was functioning.  (one was the personal guard of the Commander, however)<br/><br/>When carrying extra boarding crews, a ship loses the bonuses of the components carrying the crews, and increases all morale losses by 1, plus 1 more for each additional crew beyond the second, due to overcrowding.  Ships with extra boarding crews reduce their supply duration by half