The Engine order telegraphs
An Engine Order Telegraph, or EOT, is used to send orders to the engine room. There are two sets of EOTs, one in the control room, and one in the conning tower. The left and right EOT represent the port and starboard engine, and can be operated independently of each other. Holding shift while clicking an order change will change both EOTs simultaneously.
The EOT can be used to set various speeds, forward and backward. A higher speed makes more noise, and uses more energy. While in electric mode, the u boat’s battery reserves are drained while moving. The cost of moving increases quadratically with speed, so moving at a slow pace is much more efficient. If the u boat is surfaced, the diesel engines may be started.
The diesel engines are faster, and can be used to charge the batteries. To start charging, start the diesel engines, and select charge battery. The u boat will continue to charge until the diesels are turned off, or the battery is full. The faster the u boat moves, the slower it charges the batteries. If the u boat dives with the diesels still running, the diesels will flood.
Use the EOT by clicking on it. The left and right EOT represent the port and starboard engine, and can be operated independently of each other. Holding shift while clicking an order change will change both EOTs simultaneously. Selecting the orders written in black makes the boat run forward and the red orders makes it run backward.