The following is an extract from Annie Boyd's superb 'Koombana Days':
'The Clayton’s system consisted mainly of a combustion chamber and
a large fan. In the combustion chamber, rolled sheets of sulphur, placed
on trays, were ignited to produce a large volume of sulphur dioxide gas
which was then forced into the sealed hold to starve the fire of oxygen.
For most fires the method was extremely effective. If time were allowed
for the hold to cool before fresh air was admitted, total extinguishment
was the usual result. But spontaneous combustion in wool or fodder was
notoriously difficult to extinguish, because the seat of the fire was hidden
somewhere within a steaming, smoking mass. The problem for the
Clayton’s apparatus, or for any system that relied upon a retardant gas,
was that the gas did not always penetrate to where it was most needed.
Naked flames on the outside of a wool bale would be quickly suppressed,
while the glowing source remained hidden and insulated, like the buried
ashes of a camp fire. After ordering the system activated, Rees allowed it to run continuously
for thirty hours before opening the hold to check the results. As fresh
air flowed in, the fire quickly re-established itself. He ordered the hold
resealed and the process begun again.'
This extract gives an excellent description of the Clayton's firefighting system. But as the author points out, it had limitations. A fire deep within a coal pile would not necessarily respond to this method. Smouldering coal deep within the pile would be immune to reduced oxygen within the air space.
It was an unwise practice to seal off a coal bunker hoping that the sulphur dioxide would extinguish such a fire. Sealing off a bunker also prevented crew from working down the pile and monitoring progress of the fire.
I believe there was a fire on the Waratah, and as in the case, December 1908, the emphasis would have been on pumping water into the affected compartment. This could be very effective but depended on the capacity to remove (bilge pumps) the excess which in turn had a direct impact on stability - ballast distribution and overall weight.
In the case of the Koombana, the fire did progress out of control - damp wool caught fire in one of the holds. Captain Rees made for the nearest port and fortunately arrived before the fire caused excessive damage and presented a threat to the souls on board. Passengers remarked that they awoke due to the smoke and found themselves in port.
The Koombana was a similar (but smaller) triple deck steamer to the Waratah. She disappeared after sailing into a cyclone off Western Australia.