[douglas]

For support ships, a single shield generator is probably enough. Depending entirely on self destruct devices, especially with designs that depend on lots of armor instead of shields, leaves you vulnerable to suicidal boarding tactics (one boarding escort for one big dreadnought warship is a really good deal for the guy with the escort, and the AI will ignore the SDD's presence). Master computers have no effect on boarding. For primarily armored warships, security stations are the best defense.