Sunday, 2 February 2014

FLAWED COPPER PIPE - THE TIP OF AN ICEBERG.

Natal Witness and Mercury, August 7, 1909

"The Mercury publishes information relative to the Waratah which tends to prove that several statements concerning the missing liner, relative to the voyage before reaching Durban, are incorrect."

Again we read about false newspaper reports delivering misinformation to the public.

"Reports are being circulated that the liner had already had her seaworthiness affected through damaged machinery before she left Durban."

"One of the Cape Town newspapers published a statement to this effect, adding that the steamer proceeded to Cape Town with her defects still unrepaired, because the work could not be effected in Durban."

"The whole of this story is entirely unfounded."

"Apart from the inaccurate reference to Durban, where of course, practically any repair to a damaged vessel can be undertaken, and expeditiously carried out - the condition of the Waratah's machinery was perfect, both when she arrived, and when she left, and she was thus reported to the Harbour Authorities, to the Collector of Customs, to Lloyd's surveyor (Captain Airth), and to the agents for the Blue Anchor Line (Messrs Cotts and Co)."

"The Waratah did have one small repair carried out here, but it was of so insignificant a character that the cost did not exceed 3 pounds 15 shillings.  Mr Booth (of R Booth and Son, engineers, Greyville), who effected the repair, as being the removal of a suction pipe from one of the auxiliary feed pipes, from what is known as the Weirs pump to the heater, which raises the temperature of the condensed water preparatory to its being fed again into the boilers."

Central to understanding the operation of steam propulsion is the basic steam cycle, a process in which we generate steam in a boiler, condense the steam into water, and finally feed the water back to the boiler. This is accomplished by a series of heat transfers and work exchanges throughout system..
There are limits to how much steam a boiler can produce. If excessive demand for steam is placed on a boiler, the amount of fuel or air which can be supplied to the boiler may be physically limited. This is the endpoint of combustion and it will result in improper combustion in the boiler furnace. Beyond this point, increased steam demand can actually cause liquid water to leave the boiler along with steam. This is the endpoint of moisture carry over and it is destructive to steam pipes, turbines, and other equipment. Eventually, excessive steam demand can even cause a disruption of the natural circulation process discussed previously. This is the endpoint of natural circulation. The superheater (heater) is usually a four pass heat exchanger closer to the flames of combustion than the generating tubes. As the steam travels through the superheater, its temperature is raised to 800-850F. Steam exiting the superheater is at 600 psig and referred to as "superheated", or more commonly, "main" steam.

"The job was quite a small one, and was needed owing to a fracture which having occurred in the pipe - a copper one - due to a flaw in the metal. This took place some time before the steamer's arrival in Durban, on the voyage from Australia."

The job may have been a small and inexpensive one, but the implications are very significant indeed.
If the copper pipe was flawed (and others similarly flawed) as reported, one shudders to think of steam 850 degrees F and under the equivalent pressure escaping into the engine room. In addition to this, if increased demands were placed on the boilers, incomplete combustion as stated could result in both steam and water leaving the boilers. This moisture in turn had potential to cause destruction of pipes. A breach in the copper pipe/s could theoretically cause a massive explosion which would be instant, unexpected and devastating.

"In addition to giving these particulars, Mr Booth narrates how the Waratah's engineer, Mr Hodder, told him that there had not even been a hot bearing since leaving Sydney."

"The chief engineer, referred in his conversation with Mr Booth, to a storm which the Waratah encountered after her departure from Australia, and stated that the engines maintained a speed of 12 knots through a heavy gale."

"She will stand any sea" was one of his remarks to Mr Booth.

It appears the Waratah passed her test as regards gales at sea, contrary to the Court of Inquiry's summation that the great storm of 28 July, was the first severe storm that the Waratah had encountered.

to be continued.....





reference:

www.fas.org/man/dod-101/navy/docs/swos/eng/60b-102.html



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