[Suicide Junkie]

The leaky shields are achieved with the crystalline ability.
Given a large amount of crystalline ability points, shots impacting the ship will have on average 50% of their damage absorbed.
0% = shield skipping OR armor skipping damage
20% = Quad to shields damage
33% = Double to shields damage
50% = Normal
66% = Half to shields
80% = Quarter to shields.

In some cases, such as vs very low damage weapons, the absorption percent can be higher that that.

If you make the shield generators "armor", or have leaky armor, you can have the absorption percentage fall as the shields take damage, and the crystalline ability value becomes important.