It has always been a dream of naval architects and marine engineers to make an unsinkable ship that would never sink. Every year a lot of mariners lose their life to accidents at sea. The experts made many ships in the past that they claimed to be unsinkable.
One such well known ship was the Titanic that was doomed to end in a tragedy and sank in its very first voyage. When it sank nearly 1500 people on board the vessel died. This was the point when it was realised that perhaps man cannot fight the forces of nature.
Though the reasons for sinking of various ships could be different, and incidents such as the titanic could be possibly attributed to natural conditions, still in many cases the root cause could possibly be found in either carelessness or human complacency. So thought it might not be practically possible to manufacture unsinkable ships which do not fail under any circumstances, many mechanisms and safety features were devised which certainly reduced the risk to a great degree.
There have been incidents when ships went down for as simple a reason as the bulkhead doors not being closed properly and water gushed in during bad weather. There have also been incidents where bulkhead doors acted as a trap for the seaman where their locks could not be opened and this led to many deaths and accidents.
Hence a need was felt to device a system whereby bulkhead doors were fitted and had a provision for central locking from the single control point, normally the bridge in case of any emergency.
This apparatus that was used in this process was called the Stone Lloyd system. The apparatus became so successful that it was slowly used in most of the ships and currently is found on most water crafts.
Basically a bulkhead door refers to a opening at the exterior of the ship which can be closed in a watertight manner to prevent any inflow of water. Since there are many such bulkhead doors on a large ship, the seamen could possibly forget to lock one or more of these as a matter of routine.
bulkhead doors
With the invention of the bulkhead doors which could be closed from the deck or which could be connected to sensors and close automatically in case of conditions like fire (sensed by fire sensors) or unnoticed flooding (sensed by bilge float alarm), the safety factors has certainly gone up quite a lot.
Yet there is also a provision for manual override of the automatic closing mechanism for the simple reason that if any person is trapped inside the area, he or she could escape and not be a victim inside.
When such bulkhead doors was first launched, the crew members of the ships were against the idea. They did not like the thought of the doors being automatically being locked from the bridge. They thought that these doors will be fatal to them and they will be trapped inside when the ship hits bad weather.
They took some time to understand that this would actually help them. The bulkhead doors had levers at both the sides of the door by just lifting these levers the doors could be opened. This would ensure that the crew members can pass through the same. These can same lives and also ensure safety. The crew members were finally convinced and they accepted the idea.
The captain of the ship must be careful with the bulkhead doors as a little tampering with these doors can create a big problem. It is noted that the crew members tamper these doors and they don’t close later. To make the mechanism even better the captain can see the indicators that show which door is open and which is not. This will help them to check if the bulkhead doors are working fine. This also ensures safety of the ship.
The experts believe that hydraulic power is the best way to control the bulkhead doors this is why this mechanism is used. The hydraulic pressure pump has four capacious patent system and hydraulic accumulator these can supply power in the event of pumps stopping. The hydraulic and accumulators are above the water line. These pumps therefore cannot be going out of action due to the rising level of water.
The branch from the pressure mains go up to the bridge. Here the pressure can be turned into either of the two pilot mains. These run through the whole of the ship. These operate controlling valve at each door. These cause the door to close. The pilot main operates the power for the reverse action this causes the door to open.
These pumps are good as they need more force to open and less force to close. The doors can also be operated by hand wheel. These will ensure that the door can be opened and closed at times of emergency too. This is just like a backup plan that makes assurance doubly sure.
The crew are made aware of the bulkhead doors and its operations during the training sessions so that nothing goes wrong. There is a warning gong that goes on for twenty seconds before the bulkhead doors are closed. This warning gong prepares the crew. This also gives them the time to pass through the doors.
As we have already mentioned that even after the bulkhead doors closes if anyone remains inside then they can come out by using the lever. In time of fire when there is smoke around and the visibility is poor then one of the crew members hold the lever and when the lever is left after all have passed the door closes automatically. The water in the pressure mains can get over heated. This is exactly why the water is kept in constant circulation. This will keep the temperature in control. The bearings are smeared with glycerine from time to time. This ensures smooth operation of the ship. This bulkhead doors system requires good maintenance for smoother operation. This will make the joints smooth.
It has been observed that in times of emergency bulkhead doors proves to be very helpful. These ensure that the captain can close the doors in anticipation of an accident.
Some boats to ensure extra safety in time of fire fusible plugs placed in coal bunkers are used. These cause the door to close automatically. The bulkhead doors ensure safety as well as the possibility of anyone who wants to be safe to come out.
Many ships in the past were lost as the doors needed to be closed manually. This was perhaps the first step in making unsinkable ships. We will discuss some more of such contributions in our next articles which help to make ships unsinkable.
