The smoke sides of the boiler must be cleaned very diligently in a periodical manner (say once in three months) supervised by the chief engineer himself. On older ships, the economizer tubes were having clamps and such clamps must be checked very thoroughly by going inside and spending some time here because if they keep rubbing against the tubes, we will surely have a leak and it is rather difficult to find out the location of such leaks. Many junior engineers argue that we have soot blowers so why open and clean them. Such persons will learn later with experience that soot blowing is not enough.
In case of fire in the tubes, stop the engine, cover the turbocharger filter fully and shut off the blower supplying air to this filter. This will stop the air draft. After some time the fire will go away. We can introduce CO2/ DCP inside through ingenious means. Do not use soot blowers. Circulation of water should be maintained as far as practicable. Water may be used inside the casing in a well-directed manner for effecting cooling if practicable. But waiting and watching for some time is preferred. Same thing happens with under piston scavenge fire. Reduce RPM suitably, cut off fuel to effected unit and wait for 15 minutes. In most of the cases the fire will be doused. In one case, the burning material was burning close to the under piston scavenge door and one inspection glass got overheated and a hole was created in it, wearing asbestos gloves and taking cover, I had introduced foam through portable extinguisher via this hole. But, in both the cases, Chief engineer and deputy engineer must undertake thorough cleaning periodically.
A note of caution is needed here, do not wash the economizer if a long pilotage is to follow because sparks keep on coming for long and pilots get worried and may even complain. Generally the Chief leaves at this point to provide information to captain and the watch incharge makes a cup of coffee, relieved of maneuvering, till he suddenly finds hotwell overflowing and safety valve lifting. Then, there occurs big commotion. The boiler tube plugs are supplied with the new ship and kept in the spares box but with the time they vanish. It will not be out of place to say here that a junior engineer ( fifth engineer or TME) is very useful and all of us must demand that one such young person be provided on all ships. I must confess that in my long sea service, these boys helped me immensely.
While inspecting the boiler structure, the flue tube (cylindrical structure between the furnace and the tube plate) must be ultrasonically gauged. In some makes of the boilers, there is water space below the furnace bottom plate and there is some shoring structure. This bottom plate must also be cleaned and its thickness must be gauged. We are seamen and we love to perform difficult jobs.
(The views expressed by the author in the article are his/her own.)