The Culture: Superlifter Kiss My Ass

This is my interpretation of this ship from The Player of Games novel. A superlifter's purpose is towing (or slowing down) other ships to very high speed.
At first it appears in its everyday configuration, the one it uses for its own mobility. Then the traction field is deployed. This is an amplification and control system with separate relays set in three stages. The size adapts to that of the vessel being towed.