Procedure of Main Engine on Bridge and Crash Astern!!!

1. Introduction of Engine Telegraph

An engine order telegraph or EOT often also chadburn, is a communications device used on a ship for the pilot on the bridge to order engineers in the engine room to power the vessel at a certain desired speed, in early vessels, from the 19th century until about 1950, the device usually consisted of a round dial about nine inches in diameter with a knob at the center attached to one or more handles and an indicator pointer on the face of the dial. There would also be a revolution per minute (RPM) indicator worked by a hand crank. Modern EOT on vessels which still use them , use electronic light and sound signals.
Traditional EOT required a pilot wanting to change speed to ring the telegraph on the bridge moving the handle to a different position on the dial. This would ring a bell in the engine room and move their pointer to the position on the dial selected by the bridge. The engineers hear the bell and move their handle to the same position to signal their acknowledgement of the order and adjust the engine speed accordingly. Such an order is called a “bell”, for example the order for a ship’s maximum speed, flank speed, is called a “flank bell”
For urgent orders requiring rapid acceleration, the handle is moved three times so that the engine room bell is rung three times. This is called a “cavitate bell” because the rapid acceleration of the ship’s propeller will cause the water around it to cavitate, causing a lot of noise and wear on the propellers. Such noise is undesirable during conflicts because it can give away a vessel’s position.

2. Procedure of Main engine use on bridge

In our vessel, we can give the telegraph signal to the engine room but main engine can not be controlled from the bridge. The assigned officer who need to give the telegraph signal according to the master or pilot order.
When arrival or departure to/from the port of call, before using the engine, we need to get standby engine and the notice should be inform to engine room in appropriate time interval.
When we need to reduce the speed, we need to inform engine room to reduce the speed that the master or pilot order.
When we approach to harbour, we need to reduce the navigation speed to harbour speed at first and at the time we get the harbour speed we can reduce the speed by giving the telegraph signal.
After finishing the berthing, we will give to FWE (Finish with Engine) which means that main engine will not be use anymore.
When we proceed to the another port, we have to inform the engine room to increase the RPM as we require and if we posses the navigation RPM, we have to give the R/UP (Run up) engine at the time.
And then our vessel will be proceed with the sea speed and engineer will assume that no further engine manoeuvring will be used.
Every record of giving the telegraph signal should be written in the bell book with the specific time and all the times need to be synchronized with the bridge and engine room.

3. Crash astern

In a sea going vessel, unlike land transport, there are no brakes that are provided to stop the ship when need. The stopping of the vessel is done by reversing that rotational directional of the main engine and thereby the propeller. This stops or reduces the speed of the vessel heading towards the collision course.
The crash manoeuvring is usually done to avoid any type of collision or crashing of ship to any other ship or structure(Jetty,land,iceberg etc.). In this type of manoeuvring the main engine is subjected to severe stress and loading, but the safety of ship and life is assured.

4. How to perform Crash manoeuvring

Crash manoeuvring is turning the engine in opposite direction to reduce the heading speed of the ship. After certain time, the ship stops and starts streaming in astern direction. This is done by supplying starting air about 30bars from the air receiver to the engine. The stopping air is known as the brake air.
The brake air when sudden injected inside the engine cylinder, will try to resist the motion of the piston and the rotation of the propeller.

5. Procedure of Crash astern

Following procedure is to be followed when a navigational officer calls engine room and says that we have to stop immediately to avoid collision.
When there is an emergency like collision, grounding etc. the controls are transferred immediately into the engine room controls.
The bridge will give astern direction in the telegraph, acknowledge the same signal.
When the telegraph is acknowledge only the starting air cam will reverse its direction but the fuel cam will remain in its running position due to running direction interlock since engine is still running in the ahead direction.
The fuel lever in the engine room is brought to “0”
As soon as the RPM of the engine drops below 40% of the Maximum continuous rating or MCR rpm of the engine, give break air few times in short time frame.
When carrying out crash manoeuvring, some safeties need to be bypassed to avoid tripping of engine in mid of emergency.
When the ship stops and situation is under control, a detailed main engine inspection is to be carried out when there is a chance.