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Author Topic: Titanic, was the wheel turned the wrong way?  (Read 23926 times)

gingyer

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Re: Titanic, was the wheel turned the wrong way?
« Reply #50 on: October 09, 2010, 11:42:04 pm »

I thought the Oberons had conventional power plants?????

Oberon's were diesel/ electric subs definitely not nuclear
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derekwarner

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Re: Titanic, was the wheel turned the wrong way?
« Reply #51 on: October 10, 2010, 12:40:56 am »

Yes....& very quiet too.....one of our OZ Oberon Commanders got into a lot of trouble when one of his crew sold a photograph to a Perth newspaper of the USS Enterprise CV?? in the perescope cross hair viewer during a combined exercise north west of Exmouth in WA .....like  :police: this cannot happen  >>:-( >>:-( ...like this was not supposed to happen  :kiss: :police: ....but it did!

The minister for Defence at the time was that {-) {-) Mr Beazley.........& instead of egg on his shirt [he was a very messy eater onboard HMA vessels] it was his face......  %) ....

I have tried to GOOGLE this story.....but as expected ....back then it was declared by our D of D as a hoax .........to save face for our US....friends........Derek
« Last Edit: October 10, 2010, 12:48:43 am by derekwarner_decoy »
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Derek Warner

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derekwarner

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Re: Titanic, was the wheel turned the wrong way?
« Reply #52 on: October 10, 2010, 01:45:16 am »

Sorry...I know this is getting a little off track....but here is an extract from a much later incident....."New Depths in Australian - US Relations - the Collins Class Submarine"...where they acknowledge that a quiet sub can breach US defences ....Derek

"viii. American Recognition
Horden Wiltshire, former Commanding Officer of HMAS Sheean, has recorded of the
Collins submarines that the ‘media smoke screen has disguised the full potential of
the platform which, in an uncertain strategic environment, remains one of the most
versatile and potent in the Australian Defence Force’.110 The US too were soon to
discover just how potent. More positively for those associated with the Collins
project, such was the lauded but little reported, success of HMAS Waller at Nthe
RIMPAC 2000 naval exercises off Hawaii in May, that the US interest was
heightened. Despite being restricted by some aspects of its noise performance and
limitations in the combat system, Waller, in these structured events, pursued and
'sunk' a Los Angeles class nuclear submarine and in taking periscope photographs of
the aircraft carrier, Abraham Lincoln, demonstrated that it could enter into torpedo
range of the carrier denying detection.111 Just why there was such a dearth of
publicity surrounding Waller’s success may indicate further, the strength of the
interest in securing US involvement.
« Last Edit: October 10, 2010, 05:52:20 am by Martin - admin. »
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Derek Warner

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nsa66

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Re: Titanic, was the wheel turned the wrong way?
« Reply #53 on: October 10, 2010, 08:56:59 am »

On the subject of turbines and superheat, to the best of my layman's knowledge turbines generally require dry, though not necessarily superheated steam. The Isle of Man Steam Packet had been operating turbine vessels for close to fifty years before the first superheated boiler (Babcock & Wilcox sectional header type fitted to Manxman in 1955) was used.

I think (and I'm happy to be corrected in any of this) that it is the presence of condensate which leads to problems with out-of-balance forces and eventually blade erosion. How dry the exhaust from a reciprocating engine is I wouldn't know. I suspect that the overall design of the plant would a) design the main engines to leave the exhaust sufficiently dry  b) construct the turbines with adequate strength to cope with the expected saturation level  c) ensure sufficient vacuum at the condenser to minimise condensation within the engines. Certainly exhaust turbines were in use for a very long time, though I suspect that main turbine propulsion came first.
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gondolier88

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Re: Titanic, was the wheel turned the wrong way?
« Reply #54 on: October 10, 2010, 11:35:13 am »

I thought the Oberons had conventional power plants?????

You may be right Colin, one of the lads at work was project manager at Vickers on the first nuke subs there, I thought those were the O-boats, but I may be wrong.

Either way, the first nuke powered subs built there were turbines of course, and they had no superheaters and their turbine's worked with seven stages, the last being almost water; the real point of the post.

On the subject of turbines and superheat, to the best of my layman's knowledge turbines generally require dry, though not necessarily superheated steam. The Isle of Man Steam Packet had been operating turbine vessels for close to fifty years before the first superheated boiler (Babcock & Wilcox sectional header type fitted to Manxman in 1955) was used.

I think (and I'm happy to be corrected in any of this) that it is the presence of condensate which leads to problems with out-of-balance forces and eventually blade erosion. How dry the exhaust from a reciprocating engine is I wouldn't know. I suspect that the overall design of the plant would a) design the main engines to leave the exhaust sufficiently dry  b) construct the turbines with adequate strength to cope with the expected saturation level  c) ensure sufficient vacuum at the condenser to minimise condensation within the engines. Certainly exhaust turbines were in use for a very long time, though I suspect that main turbine propulsion came first.

You are correct in saying it is condensate which is the major unbalancing force in a turbine- rather like throwing ball bearings into a food blender. The turbines I mentioned in the early nuke subs at Barrow had specially designed blades on the last two stages to cope with the high saturation.

Recip's need dry steam in the cylinders, however the exaust in a condensing plant should be as wet and cool as possible- tjis means it's giving up as much energy as possible in working the engines, which as you also correctly say is reliant on having a large air pump to shift as much condensate as possible.

Turbines and exhaust turbines were actually developed along with each other as they were seperate technologies in themselves, yet lent themselves to being utilised in the same engineroom. Certainly in some o;ld steam manuals I have it mentions them both together around 1911 as bedfellows.

Greg
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nsa66

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Re: Titanic, was the wheel turned the wrong way?
« Reply #55 on: October 11, 2010, 09:30:48 am »

Just out of interest, since yesterday's post I've been doing a bit of digging on the nature of steam. There seems to be a bit of a grey area in the definition of wet, saturated, dry and superheated steam.

From my experience of land-based steam usage (primarily for heating purposes) I have always used the term 'dry' quite loosely to describe steam which contains no obvious water droplets. In this instance it would be fair to say that the steam leaving the boiler was saturated, and indeed dry, but would become progressively wetter as it cooled on the way to its destination. Even with the best lagging in the world there must be some degree of condensate mist bound up in the flow by the time the steam comes to be used. The only way to avoid this situation is by superheating the saturated steam so that any cooling does not progress beyond the point at which condensation appears - i.e. the steam continues to behave as a gas until it begins to work expansively.

It appears that there are only really two important definitions here:

1. SATURATED STEAM - Steam at which the temperature of the steam corresponds to its boiling point at its current pressure.

2. SUPERHEATED STEAM - Steam which has been further heated until its temperature exceeds its boiling point at the current pressure.

From this it can be seen that any steam even fractionally cooler than Saturation Point will contain condensate and could be described as wet. Saturation therefore describes a boundary between wet and superheated steam. So DRY steam has to be either precisely on the boundary or it has to be superheated.

Thus much so-called dry steam is technically at least partly wet. In a theoretical sense there cannot be any absolutely dry steam in a non-superheated installation. In practice I think my definition of dry steam being that which contains no excessive presence of water droplets is probably the one which is generally recognised.
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nick_75au

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Re: Titanic, was the wheel turned the wrong way?
« Reply #56 on: October 11, 2010, 09:59:07 am »

Doesn't superheat depend on pressure as well as temp, Ie steam could still be considered superheated at 70 Deg C providing the absolute pressure was at -11 psi ( cheated a little here and looked it up) ;D
Most turbines use condensers after the final stage to ensure the maximum is extracted out of the steam, I know power stations utilise wast heat in between turbine stages as well to reheat the lower pressure steam.

Nick
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tony52

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Re: Titanic, was the wheel turned the wrong way?
« Reply #57 on: October 11, 2010, 10:00:59 am »

Like yourself nsa66 I have been further researching this subject and I hope you don't mind me adding the following to your research. Again like yourself my experience is of land based steam (mainly for heating purposes) and throughout the distribution network the steam mains would fall and be trapped at the lowest part, commonly known as a dirt leg, this would be to keep the saturated steam as dry as is practical. Steam mains were never designed with level pipe runs and branch 'take offs' were always on the top. Sometimes when a steam pressure reducing station was used a degree of superheat would occur over the reducing valve's seat.

Returning to the Titanic's power plant installation I came across this on tinternet. The article shows (in Part 3) that this type of installation, which uses a turbine to be driven from the exhaust steam from a recip plant was to save coal, rather than increase speed. The item's author is not 100% correct as the Titanic's tonnage is stated as 60,000 whereas Colin Bishop has already identified this to be incorrect.

http://www.history.rochester.edu/steam/parsons/part1.html

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nsa66

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Re: Titanic, was the wheel turned the wrong way?
« Reply #58 on: October 11, 2010, 10:06:41 am »

Doesn't superheat depend on pressure as well as temp, Ie steam could still be considered superheated at 70 Deg C providing the absolute pressure was at -11 psi


Yes, that's right. The definition I have is that Superheated Steam has to have a temperature which is above its boiling point at its current pressure. So yes, if the BP of steam at -11psi was less than 70c then steam at 70c would be superheated.
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nsa66

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Re: Titanic, was the wheel turned the wrong way?
« Reply #59 on: October 11, 2010, 10:10:59 am »

.. steam mains would fall and be trapped at the lowest part, commonly known as a dirt leg ...


Oh yes, and steam traps seemed to give trouble in inverse proportion to their size. The smaller the trap the bigger the pain in the @r5e!
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tony52

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Re: Titanic, was the wheel turned the wrong way?
« Reply #60 on: October 11, 2010, 12:18:19 pm »

the bigger the pain in the @r5e!

Far worse were Spirax's modern replacement of the Ogden Pump. That was a pain in the ****

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nsa66

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Re: Titanic, was the wheel turned the wrong way?
« Reply #61 on: October 11, 2010, 12:48:54 pm »

Far worse were Spirax's modern replacement of the Ogden Pump. That was a pain in the ****



Oh yes I remember it well. Only ever saw the Spirax and it was not held in the highest regard by those familiar with the "Oggy". Why pump the condensate back to the boiler when you can leave it sitting in the pipework. Someone's bound to come and drain it off eventually.
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gondolier88

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Re: Titanic, was the wheel turned the wrong way?
« Reply #62 on: October 11, 2010, 09:42:49 pm »

From my experience of land-based steam usage (primarily for heating purposes) I have always used the term 'dry' quite loosely to describe steam which contains no obvious water droplets. In this instance it would be fair to say that the steam leaving the boiler was saturated, and indeed dry, but would become progressively wetter as it cooled on the way to its destination. Even with the best lagging in the world there must be some degree of condensate mist bound up in the flow by the time the steam comes to be used. The only way to avoid this situation is by superheating the saturated steam so that any cooling does not progress beyond the point at which condensation appears - i.e. the steam continues to behave as a gas until it begins to work expansively.

It appears that there are only really two important definitions here:

1. SATURATED STEAM - Steam at which the temperature of the steam corresponds to its boiling point at its current pressure.

2. SUPERHEATED STEAM - Steam which has been further heated until its temperature exceeds its boiling point at the current pressure.

From this it can be seen that any steam even fractionally cooler than Saturation Point will contain condensate and could be described as wet. Saturation therefore describes a boundary between wet and superheated steam. So DRY steam has to be either precisely on the boundary or it has to be superheated.

Thus much so-called dry steam is technically at least partly wet. In a theoretical sense there cannot be any absolutely dry steam in a non-superheated installation. In practice I think my definition of dry steam being that which contains no excessive presence of water droplets is probably the one which is generally recognised.

You are correct on every count- permit me to clarify one point though- DRY STEAM is the boundary line between superheat and saturated- ANY steam taken from the boiler is going to be saturated, no matter what pressure it is at (though this doesn't really include flash steam for anyone that feels like being pedantic), however this can be overcome by the use of a STEAM DRYER, this usually looks very similar to a superheater but differs in detail- it has far less surface area and usually a single pass, allowing the steam to move at the same velocity as it would in the main steam pipe.

The purpose of this device is to keep the steam at the same temperature (within a few degrees) but drys it very well.

The reason for this device was that Recips with superheated steam needed constant maintainance- the high pressures and temperatures involved meant slide valves couldn't be used and had to have piston valves- which need a good oil film to work reliably- something that is hard at superheat temperatures.

Greg
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nsa66

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Re: Titanic, was the wheel turned the wrong way?
« Reply #63 on: October 14, 2010, 10:23:02 pm »

Thanks Gondolier, that tidies up the definitions nicely.

The description of the "steam dryer" is interesting. I'm not sure I've come across that before (or if I have, I may have confused it with a superheater). Would the dryer be incorporated into the boiler in the same way as a superheater? Whereabouts would this be fitted in, say, a scotch boiler?
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gondolier88

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Re: Titanic, was the wheel turned the wrong way?
« Reply #64 on: October 15, 2010, 10:56:00 am »

Hi nsa66,

In a Scotch it would normally be located in the dryback combustion chamber- if it was a wetback I imagine it would be in the flue smokebox, though I can't say I've seen any diagrams of them used in a wetback.

Greg

Ps- a quick search on Google books with 'steam dryer' brought up quite a few interesting publications with the definition and practical use of the 'steam dryer'.
« Last Edit: October 15, 2010, 11:05:50 am by gondolier88 »
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victorian

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Re: Titanic, was the wheel turned the wrong way?
« Reply #65 on: October 16, 2010, 04:46:25 pm »

There is one book (actually two very large volumes) that actually contains facts in immense detail about these ships rather than endless speculation. It's called "Titanic": The Ship Magnificent and has a web site here. The content is of great interest to period ship modellers and explains the ship's fittings as well as the detailed construction of the hull and machinery. Copies are on Amazon at modest prices (Vol1 is most likely to be of interest to us) and as a bonus it doesn't contain a single sinking theory or survivor's recollection!
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nsa66

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Re: Titanic, was the wheel turned the wrong way?
« Reply #66 on: October 18, 2010, 03:12:52 pm »

... this doesn't really include flash steam for anyone that feels like being pedantic ...

Am I right in assuming that "flash steam" is essentially superheated steam in that (due to the nature of a flash boiler) it is further heated away from contact with the water - i.e. in effect the flash boiler acts as both steam generator and superheater in a single unit?

I have never come across flash steam except in magazine articles describing its use in very high speed steam-powered models. Has there been much use of flash steam (as opposed to conventionally generated superheated steam) in full size vessels? I suppose early attempts at high-speed running may have been candidates - light weight installation etc.
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gondolier88

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Re: Titanic, was the wheel turned the wrong way?
« Reply #67 on: October 18, 2010, 10:04:45 pm »

Am I right in assuming that "flash steam" is essentially superheated steam in that (due to the nature of a flash boiler) it is further heated away from contact with the water - i.e. in effect the flash boiler acts as both steam generator and superheater in a single unit?

Yes, you assume correctly- the pressure vessel is kept at a very hot temperature- 'dull straw' if you were annealing steel to the same colour.

Some experiments (by White Steam Cars Inc, if I remember correctly) used a thick steel barrel at around 30" dia wrapped in spring steel to an overall thickness of around 2" had working pressures of 1500psi. Though quite how you would use steam at that pressure and temperature in a reciprocating engine I don't know!!!

We have a flash steam plant at the Steamboat Museum- SL Bat has a Stanley Steam Car boiler and Lifu burner. It has around 200 1/2" steel tubes in a 24" dia X 30" barrel supplying a 14hp Vosper-Thorneycroft compound engine.

Greg
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Bryan Young

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Re: Titanic, was the wheel turned the wrong way?
« Reply #68 on: October 19, 2010, 07:32:18 pm »

We seem to have digressed just a little from "Titanic" to an exposition on semantics by members of the dirty boilersuit brigade. How did that happen? I'm sure that there must be other web sites where Impulse turbines versus reaction ones can be argued. Steam is steam as far as most of us are concerned. Normal, flash, superheated or just the stuff coming out of a kettle spout is enough.
GIVE IT A REST for goodness sake! Either that, or take it somewhere else.
Nothing against the engineering fraternity, but really, is this the place for all that? BY.
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gondolier88

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Re: Titanic, was the wheel turned the wrong way?
« Reply #69 on: October 19, 2010, 08:36:25 pm »

Forgive me Bryan, but are you not the author of one of the longest posts on the forum regarding your experiences and exploits while at sea- but this is a model boat forum, not an online memoir?

I read your posts, not always understanding what you write- not always wishing to- yet I understand your experiences bring aspects of the hobby to life for modellers that may never have even been on a boat, yet alone to sea for any period of time.

Perhaps you could be gracious enough to realise that not everyone is interested in you, yet we don't tell you so (before now).

Best of regards and no hard feelings,

Greg
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Bryan Young

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Re: Titanic, was the wheel turned the wrong way?
« Reply #70 on: October 19, 2010, 09:39:31 pm »

Forgive me Bryan, but are you not the author of one of the longest posts on the forum regarding your experiences and exploits while at sea- but this is a model boat forum, not an online memoir?

I read your posts, not always understanding what you write- not always wishing to- yet I understand your experiences bring aspects of the hobby to life for modellers that may never have even been on a boat, yet alone to sea for any period of time.

Perhaps you could be gracious enough to realise that not everyone is interested in you, yet we don't tell you so (before now).

Best of regards and no hard feelings,

Greg
Point taken. Put it down to an age related moment. Sorry.
But if you can't understand what I'm writing about then perhaps I should just quit now instead of befuddling others.
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gondolier88

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Re: Titanic, was the wheel turned the wrong way?
« Reply #71 on: October 19, 2010, 11:04:05 pm »

Point taken. Put it down to an age related moment. Sorry.
But if you can't understand what I'm writing about then perhaps I should just quit now instead of befuddling others.

Apology accepted :-))

If we understood everything we would never ask questions- as I said I sometimes feel I don't wish to understand, feeling that an understanding would not enlighten me in any way- a little knowlege and all that, though perhaps also an arrogance on my part.

Now that is not to say that 100, 200, 300 people havn't read your posts and have gone on to research some little snippet of information or anacdote, perhaps knowing freinds or relatives in similar situations that never talk about thier experiences, whatever, there are many people, including myself, that look forward to your postings and I sincerely hope you don't stop any time soon.

Greg
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BarryM

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Re: Titanic, was the wheel turned the wrong way?
« Reply #72 on: October 19, 2010, 11:04:47 pm »

Bryan,

As a fully paid up deep-sea member of the Dirty Boiler Suit Divinity I can only extend my sympathy to you in your  unenlightened condition which prevents you appreciating the true glory of steam.

On the other hand, as the best story-teller on the forum bar none, I suggest that you ignore any tetchy lake paddler's comments and carry on regardless.  :-))

Barry M
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tony52

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Re: Titanic, was the wheel turned the wrong way?
« Reply #73 on: October 19, 2010, 11:18:41 pm »

Bryan does make a valid point in that threads do go off the original subject, and this is not something I would even attempt to have an answer for.
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pugwash

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Re: Titanic, was the wheel turned the wrong way?
« Reply #74 on: October 19, 2010, 11:33:28 pm »

Greg 24900 people can't be wrong? Thats how many have read and most probably enjoyed Bryans post's
I think only   "name that ship" or "name that part" are more popular.  It is far more lucid and relates more
to ships and crews and other things nautical than some of the dross subjects that get created.
Geoff
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