A defect in the hull structure, which could have been caused by grounding, berthing, or collision damage, or, more likely, a defect in the sea water pipeline system, could have led to flooding in the engine room. Both of these scenarios are possible.
There are some measures that can be taken in order to prevent or alleviate the flooding and I will mention them below. Please be aware that, although those measures are generally applicable, some of them can be vessel specific, therefore I would strongly advise to check the specific requirements for your vessel.
- Perform routine maintenance on the outside of pipelines, including tightening slack supports and replacing broken U bolts on pipe brackets, in order to minimize fretting in the path of support structures.
- Make sure that each of the ship’s side valves is used on a regular basis so that they can be easily operated whenever it is necessary. Valves that are normally open, such as the fire pump suction valves, should be closed and reopened on a regular basis to prevent a buildup of marine growth.
- Before opening any sea water filters for cleaning, make certain that the isolating valves are in their fully closed position by opening the vent in the cover of the filter. In any event, the cover joint needs to be broken open before any of the cover bolts can be removed.
- Care must always be taken when removing covers or opening any part of the sea water pipe system because valves that are indicated as being closed may not be fully closed. This applies to opening coolers and pipelines anywhere in the system.
- Caution is always required when opening any part of the sea water pipe system. Before removing the covers from any gate valves or through cocks that are used for draining and venting, you should rodding them to ensure that they are clear.
- If the source of the rapid ingress cannot be identified, close all remotely operated sea and ship side valves. This applies to both the ship and the sea. The completion of this action presupposes that the levels are now higher than the floor plates.
- Personnel should be familiar with the location of the bilge suctions and the pumps that may be utilized for bilge pumping duties. On some vessels, ship side valves can be closed from the remote stand if necessary. In addition to this, they should be familiar with the location of the main sea suction and the overboard valves, and they should be aware of which main sea suction is currently being utilized.
- The emergency bilge suction valve needs to be used on a consistent basis in order to function properly.
- After use, pipe cocks and caps with a double bottom sounding should be fastened securely.
In the engine room there are few pumps available for bilge pumping duties and I will mention few of them, but as I specified above every ship has its own particularities and you will need to be aware of them.
The engine room bilge pump is able to take suction from the engine room bilge main, but it is unable to discharge water overboard. Instead, water can only be discharged, usually to the following locations:
- The oily bilge tank
- The clean bilge tank.
- Cargo bilge holding tank (if available)
- Shore connections, which can be found on the upper deck, to either port or starboard side.
Suction can be drawn from the bilge main in the engine room by both the fire pump and the general service pump. Suction can also be drawn from a direct engine room bilge suction, which is usually situated at the forward end of the engine room. This suction can be drawn by one of the fire and general service pump.
Both the fire pumps and the general service pumps have the capability of discharging water straight overboard.
The cargo bilge pump (if available) takes suction from the bilge main located in the engine room. The water that is collected by the cargo bilge pumps can be discharged directly overboard.
Individual feed pump for the Oily Water Separator, if available, takes suction from clean bilge tank and the oily water separator is responsible for discharging the water directly overboard.
On some vessels one of the pump for the central seawater cooling system gets the suction it needs from its very own emergency bilge suction, which is controlled by an extended spindle that is positioned above the floor plate level.
On some other vessels, the emergency bilge suction is installed on the suction side of one of the ballast pumps. The reason of choosing these pumps (sea water cooling, ballast pumps) is mainly because of their high flow capacity and direct connection overboard.
Checking and cleaning the bilge suction strainers ought to be done whenever the opportunity presents itself. The likelihood of a strainer getting clogged and difficult to clear as a result of subsequent floods will be decreased if the strainer is checked and cleaned on a regular basis.
It is essential to get any bilge well that has an alarm on it down to the empty level as quickly as possible in order to provide as much advanced notice as possible in the event that flooding takes place.
Because the allocated water pump can be utilized to pump the bilges directly overboard, its use is restricted to only when an emergency situation arises. There is no 15ppm monitor installed in the discharge pipe because the sole purpose of this pump is to assist in emergency bilge pumping operations. Either flooding will be visually detected or it will be picked up by the engine room bilge well alarm system within a short period of time. Because of this, it is imperative that the duty engineer visually inspect any abnormality with the bilge alarm system, such as an unexpected or recurring alarm or an alarm that fails to clear.
In case of emergency, once the duty engineer has established that there is a flooding situation, he/she should proceed immediately to the nearest telephone and inform the bridge of the situation. The duty officer on the bridge should raise the alarm, as this will summon assistance. It should be noted that the duty engineer could also call the ship’s control centre if they suspect the wheelhouse to be unmanned (during port stay), or activate the general alarm if no reply is received.
The bilge suction valve is a manually operated valve so it must be opened by the duty engineer before the pump is started. The pump can be started also from local position and overboard valves can be opened from local solenoid panel or manually if here is no remote control on it. All of the other remotely operated sea or ballast system valves should be closed.
It is important to remember that when the pump has picked up suction on the bilges and the flood level is under control, the pump is not allowed to lose suction. The sea water suction should be utilised to control the rate at which flood water is removed until such times as the source of the flooding can be identified and eliminated.
Also, it is important to note that in case of emergency where the safety of the ship or personnel is involved the bilges can be pumped directly overboard, otherwise it must be ensured that no local or international anti-pollution regulations will be contravened. Pumping machinery spaces bilges overboard must be conducted using an oil content monitor EXCEPT in an emergency.
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