Cort bow thruster

[RTNerd]

According to the Society of Naval Architects and Marine Engineers paper on the Cort,
"The decision to use two tunnels rather than one was based on thruster diameter and desire to keep the tunnels submerged at light draft. A single tunnel would have required a larger diameter (at the time) and necessitated a deeper draft to keep it submerged"

The thruster and unloading system motors are modified DC railroad traction motors rated 750 hp each with intermittent power capability of 1000 HP.

[Guest]

She has twin bow and stern thrusters. I would assume it's for when she's empty and riding high so that they're still effective where a large one might not be completely submerged.

[GrohsPhotography]

She has two bow thruster forward and two aft thrusters aft.

[Guest]

What is the reason for the cort having two tunnels for a bow thruster, or is one ballast inlet or outlet?