1. Equip a Crew Theme of all females.
2. Equip Special Lieutenants that are all female. You can also just equip no Special Lieutenants.
3. Find an enemy ship and damage it until it anchors. (This is when you could normally board.)
4. Position the Adrestia perpendicular to the enemy ship.
5. Ram the enemy ship at full speed. This should cleave them in half, unlocking the achievement.