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Author Topic: 19th Century Reversing  (Read 3336 times)

BarryM

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19th Century Reversing
« on: March 20, 2010, 07:43:05 PM »

Prompted by the thread querying the reversing of marine diesel engines, I quote from the Marine Engineers Review and an article describing marine engineering in the late 19th Century.

"The low pressure paddle engines were very difficult to manoeuvre. They were equipped with a slide valve operated by a single loose eccentric on the paddle shaft through a disconnecting eccentric rod. This rod had a 'grab' or 'hook' at its inner end which engaged the valve spindle but could be released when stopping or manoeuvring. To reverse the engine, the eccentric rod was lifted clear of the valve spindle and the slide valve, that could weigh up to 60lb, worked by hand into mid-position, thus effectively stopping the engine while main steam was kept full on. The valve was then moved to reverse the piston stroke and when the piston started to drive astern, the eccentric rod was hooked back onto the valve spindle to run astern."

Apart from the fact that this arrangement would give the Bridge pause before they asked for too many engine movements, the mind boggles at the acrobatics and strength needed to reverse while having to maintain balnce on a moving platform.  Things (and men) were different then.

Barry M
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Bryan Young

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Re: 19th Century Reversing
« Reply #1 on: March 20, 2010, 08:10:20 PM »

Not so different at all Barry. Berthing an LSL backwards (or forwards even) took some forethought. I suppose it was a bit like having a pre-selector gearbox in ones head. Get it wrong and yet another letter beginning "We fail to understand...etc.). But (however it was done) the Steam Turbine guys were quick. BY.
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Colin Bishop

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Re: 19th Century Reversing
« Reply #2 on: March 20, 2010, 08:26:45 PM »

The Swiss lake paddle steamers have a technique of almost instant reversing which is quite amazing to watch.

Colin
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BarryM

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Re: 19th Century Reversing
« Reply #3 on: March 20, 2010, 10:50:01 PM »

Not so different at all Barry. Berthing an LSL backwards (or forwards even) took some forethought. I suppose it was a bit like having a pre-selector gearbox in ones head. Get it wrong and yet another letter beginning "We fail to understand...etc.). But (however it was done) the Steam Turbine guys were quick. BY.
Bryan,
It may have taken some forethought on the Bridge but the act of physically unhooking b*****y great eccentrics with valves under full pressure and swinging the whole lot over and then timing the re-hooking on again is mind-boggling to them what can appreciate what the description depicts. By comparison, manoevring modern turbines and diesels is a doddle.
Manoevring turbines was always very satisfying (unlike manoevring diesels when you were never 100% sure the damn thing would start); with a good team on the boiler front, spinning the throttles and hearing the whine of the turbines and the rumble of the gearbox was music to my ears.

Barry M
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Bryan Young

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Re: 19th Century Reversing
« Reply #4 on: March 21, 2010, 07:37:02 PM »

Bryan,
It may have taken some forethought on the Bridge but the act of physically unhooking b*****y great eccentrics with valves under full pressure and swinging the whole lot over and then timing the re-hooking on again is mind-boggling to them what can appreciate what the description depicts. By comparison, manoevring modern turbines and diesels is a doddle.
Manoevring turbines was always very satisfying (unlike manoevring diesels when you were never 100% sure the damn thing would start); with a good team on the boiler front, spinning the throttles and hearing the whine of the turbines and the rumble of the gearbox was music to my ears.

Barry M
Once again, a lovely answer.  But the "Bridge forethought" was not (in the early days) a matter for consideration. When the RFA "took over" the running of the LSLs the Ch.Engineer (under that regime) was the only officer allowed to operate the controls. As you may well imagine, this stuck in the throat a bit as far as the bridge staff were concerned. It was all a matter of education. Even people who remain clean and free of oil and grease stains can prove themselves receptive to what were considered to be the "black arts". Quick learners, us bridge lot.
But the main thing was to retain......or re-establish.....some sort of re-habilitation between the 2 departments. A lot of consideration was given to this problem by me , as all I had to do was to wander back and forth across the wheelhouse, take a bearing now and again and ponder the universe.
I got over this by heaving the "spare" (little) radar into the MCR, and giving the engineers a set of oudated charts (things they would normally have used as gaskets or something), and inviting off-duty engineers to the bridge at points of "stress" (as long as they kept their gob shut). A sense of "togetherness" quite quickly followed. But I never really managed to get the other deck officers to reciprocate (an engineering term?), but the clankies appreciated it. And so build relationships. BY.
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Bunkerbarge

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Re: 19th Century Reversing
« Reply #5 on: March 21, 2010, 08:45:55 PM »

I'll add an interesting story here.

Many years ago I considered myself lucky to be sailing on the last Doxford ever to go into service.  Doxford had pushed the envelope as far as they could to produce an engine that they hoped would compete with the likes of Sulzer and Wartsilsa and so to try to drag the opposed piston idea kicking and screaming into the competition they built a three cylinder medium speed opposed piston engine.  Fascinating to watch and an unbeleivable crankcase abd turned upside down everything I knew about engines up to that point.  It took about 10 minmutes to remove the top piston and get into the liner but about 2 hours to change a dam injector!!  Anyway the big problem was ring wear due to the increased speed and subsequent loss of compression.  The answer was to pour buckets of oil around the top piston during manoeuvring and seal the rings to ensure reliable starting. 

One morning at about 02.00 hrs we were manoeuvring in to Eastham Lock at the start of the ship canal and the Second Engineer was in the ECR.  I had gone out onto the aft deck for a smoke and watch us go into the lock before going down to relieve the second again, I was a fiver at the time.  The old man had been warned time and time again by the Chief that starting was not as reliable as it should be and this wouldn't improve until we could re-ring the engine so allow plenty of time for manoeuvres.  As we went into the lock and the rear gate flew past me on the aft end I thought "That's a bit brisk", then I heard the "chuff, chuff, cafuff, cafuff" from the funnel door as it tried to start.  Nothing.  Then again chuff, chuff, chuff, cafuff.  Again  nothing.  By this time I was taking the Board of Trade appropriate steps in the circumstances, i.e. very large ones!  As I reached the tops she went again, chuff, chuff, chuff, carumble, rumble, rumble.  How we missed the forward gate I have no idea but someone was on our side that night!

When we explained how close it had been to the old man he didn't seem in the slightest bit phased out by it all!!  He was Lithuanian so probably didn't realise anyway!!
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Bunkerbarge

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Re: 19th Century Reversing
« Reply #6 on: March 21, 2010, 09:47:07 PM »

As to Barry's comment about reversing a turbine as opposed to a diesel engine I'm afraid I will have to respectfully completely disagree.  My second trip to sea was on a Sulzer slow speed 7RND90 and the bridge control system failed so manoeuvring the engine had to be done from the platform.  The thing is with starting an engine of this size is it's all about the knack of using as little air as possible.  If you don't give it a big enough kick you won't get a start and you will have wasted the air.  If you give it too much you will guarrantee a start but again you will have wasted a lot of air so the measure of a good engineer was reliable starting but using a minimum of air.

If you think starting a turbine is something I don't think it can compare with starting a slow speed diesel, three storeys high with pistons 900 mm bore and weighing in at nearly two tons apiece!  Even on those opening and closing the main air start valve required all your shoulders in it and you didn't have time to mess around.  The main air valve was upside down on a Sulzer and about head height with a handwheel in the region of 3 foot across.  Once you had opened that the start lever was quite small but you had to operate the start lever with one hand and the considerably larger fuel lever with the other hand.  That also needed you to get your back into it.  Then as soon as it was running you had to close the air valve again.

I will never ever forget the unbelievable buzz though of starting one of these things manually.  Even after a few hours of standby with rotating the engineers on the platform every half an hour you still couldn't help a grin when she fired up and you adjusted the fuel lever to give you the speed to match the telegraph.  There would be a few colourfull words thrown in the direction of the bridge as well when the engine would just get to speed and the telegraph would ring stop again!
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BarryM

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Re: 19th Century Reversing
« Reply #7 on: March 22, 2010, 02:15:14 PM »

Bryan/BunkerB,

I think you two are chasing a rat up a scupper which doesn't exist. The main point I was trying to make was that 19th Century reversing on a paddler could be extremely slow, crude and physically demanding. The need of the Bridge personnel to think ahead was secondary. (Some might say that the power of thought on a Bridge was a revolutionary concept anyway but I could not possibly comment!  %) )

The reference to the manoeuvring of a steam turbine plant was to illustrate its lack of effort, simplicity and assured control compared to large marine diesels (of which I have manoeuvred far too many in my time) and BunkerB's description of manually operating a large slow-speed diesel proves my point.  There is no attempt on my part to suggest than manoeuvring a steam turbine is (usually) anything but a rather pleasant experience - and I would rather have a boiler full of steam to assure starting than a a couple of air bottles of limited capacity. Yes, juggling the air start and fuel was critical and something of an art but why make life difficult for yourself?

One time it was otherwise was during a dry-docking in Marseilles. We had initially moored at a wet berth for refit where one of the two main boilers was shut down. We then had to shift to the dry-dock on a single boiler and it was pointed out to the Old Man etc. that manoeuvring revs would be restricted and he could not expect the same response or power during the transit. "Of course, of course, I understand", he said and off we went.  Thankfully the crossing was not too far because I lost count of the number of 'Double Full Asterns" or 'Double Full Aheads' that were telegraphed. The more the Bridge failed to get the revs/response which they had been warned could not be delivered, the more frantic became the telegraph orders. We made it but only just.

Finally, I understand that Class and Government Agencies are growing concerned at the lack of manouvrability of the latest slow-speed diesels. The drive to produce the most fuel efficient plant has resulted in designs in which rev bands have become increasingly restricted at the bottom end of the range and some vessels now struggle to provide a 'Dead Slow Ahead' which is less than about 10/11 knots. Obviously this restricts the vessels ability to manoeuvre and puts greater demand on the tugs assisting.   (Now a turbine plant could be just tickled along at shaft revs of 5 RPM...) 

Cheers,

Barry M
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Bunkerbarge

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Re: 19th Century Reversing
« Reply #8 on: March 22, 2010, 04:50:19 PM »

All things are relative, as they say.  Nowadays I can have 11.75 mW of power started, up to speed, paralleled, on the board and sharing load within a minute and during the whole operation the manoeuvring of the main propulsion motors don't miss a beat or a movement.  That to me makes a turbine look slow, crude and physically demanding and I guess in years to come there will be something else to make my diesel electric plant look equally dated. 

In the meantime I suspect we will always have the same challenges and that will be to get engineers to look for the cause of a problem at the bottom rung of the ladder and not halfway up and to maintain an open, honest and respectful relationship with all other departments on the ship.
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Netleyned

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Re: 19th Century Reversing
« Reply #9 on: March 22, 2010, 05:23:28 PM »

All things are relative, as they say.  Nowadays I can have 11.75 mW of power started, up to speed, paralleled, on the board and sharing load within a minute and during the whole operation the manoeuvring of the main propulsion motors don't miss a beat or a movement.  That to me makes a turbine look slow, crude and physically demanding and I guess in years to come there will be something else to make my diesel electric plant look equally dated. 

In the meantime I suspect we will always have the same challenges and that will be to get engineers to look for the cause of a problem at the bottom rung of the ladder and not halfway up and to maintain an open, honest and respectful relationship with all other departments on the ship.

Would that be MW ?

Ned
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BarryM

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Re: 19th Century Reversing
« Reply #10 on: March 22, 2010, 05:58:11 PM »

Perhaps he's not allowed to play with the big stuff yet?

Barry M
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Colin Bishop

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Re: 19th Century Reversing
« Reply #11 on: March 22, 2010, 06:30:46 PM »

A 90,000 GRT ship seems a respectable size to me...

Colin
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BarryM

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Re: 19th Century Reversing
« Reply #12 on: March 22, 2010, 06:58:56 PM »

Just a bit underpowered with 11.75mW plant?
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Bryan Young

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Re: 19th Century Reversing
« Reply #13 on: March 22, 2010, 07:35:53 PM »

As a former deck officer I think that, in the main, I'll go along with Barry.
Far too many of my compatriots would rather have walked the streets than go "down" into an engine room and mix with the low life that lived there. After all, we had an "Officers Dining Saloon" and an "Engineers Mess". Says it all really, doesn't it.
One of my great delights was to be "off watch" on an old Cable Ship with 2 triple expansion engines during periods of heavy manouvring. Sheer dexterity and concentration. A lot of the engineers could tell, more or less instinctively, who was on the other end, and so disregarded some orders, knowing that the prior one would be cancelled out by the next. This gave me a great insight into ship handling in the future.
RFA "Retainer" had a Double Opposed Doxford engine. The top of the engine was only a few feet below a catwalk that I used to stand on and marvel at the writhing hoses and so on.
Over the years the "clankies" have been recognized as the mai "guys to go to" if you have a problem. I think that nowadays the bridge autocrat is more or less a fossilised relic...there may be a few left. Before I left the RFA the cadets training gave the deck cadets time in the engine room, and the engineer cadets time on the bridge. When I was a junior officer that would have been proffessionally suicidal, socially divisive and "frowned upon" by the owners.
And......the engineers are always up for a good natured arguement, no thumbs stuck up bums with them!. BY.
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Bunkerbarge

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Re: 19th Century Reversing
« Reply #14 on: March 22, 2010, 08:27:57 PM »

Just a bit underpowered with 11.75mW plant?

There's five of them
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BarryM

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Re: 19th Century Reversing
« Reply #15 on: March 22, 2010, 10:37:11 PM »

All 11.75 milliwatts?
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BarryM

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Re: 19th Century Reversing
« Reply #16 on: March 23, 2010, 09:16:42 AM »

"In the meantime I suspect we will always have the same challenges and that will be to get engineers to look for the cause of a problem at the bottom rung of the ladder and not halfway up and to maintain an open, honest and respectful relationship with all other departments on the ship."

This is very Zen (I think) but putting it through my Plain English Transcriber I think it means that Engineers are an unworthy species who should always hold themselves responsible for everything rather than question the actions of others and try to maintain goodwill with other disciplines. While I don't have a problem with the latter sentiment, the former is Bunk!

Oh and thank you Bryan for maintaining a sense of humour and proportion.

Barry M
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dreadnought72

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Re: 19th Century Reversing
« Reply #17 on: March 23, 2010, 06:45:43 PM »

I'm rather glad we didn't reverse in the 19th century. Else by now it'd be stuck in the late 1600's ...  %%

Andy - probably needing a lie-down
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