The Original Boiler
The boiler was wrought iron, rather than steel which made welding in patches a “no no” so it was important to check the state of the boiler shell. The shell and tubeplates showed little signs of corrosion though the tubes were totally life expired. It was obvious that the boiler would need to be retubed.The boiler inspector indicated that once retubed a ticket for 30psi was a possibility. As all we really wanted to do was turn the engine over we set out on that path thinking to preserve as much of the old as possible. New tubes were ordered and we got to work removing the old ones. There are 170 tubes and only 5 hand holes to access them for removal so this was no small task. The tubes were too far gone to hope to pull them out through the tube plates. They were cut close to the tubeplate at each end then manoeuvred out through the hand holes. It was particularly difficult to get the first ones out having to manipulate them past the remaining tubes and through a small hand hole,
When we got down to the last few Jo was removing the stubs of the cut tubes at the firebox end and set up a light to help see more clearly. Unfortunately the light showed up previously unnoticed cracks in the plate between the tubes.
The boiler inspector was called in to give his opinion on how to proceed. His view was that a specialty welder could probably repair the cracks but in his experience there was a very high chance that the plate had crystallized and that new cracks would occur the first time it was steamed. To have put in 170 tubes only to have to remove them to replace the tube plate was out of the question so it was decided to make a new boiler.