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Discussion Starter #1 (Edited)
I had thought that the majority of my sea time was spent with LB Doxfords but looking back into my discharge book I realise that was not the case – it just seemed that way ‘cos lots of “stuff” happen during those times!
The Doxford engine, with its uniflow scavenging and constant pressure fuel injection, certainly had the best fuel consumption of its time and, with no combustion loads transmitted to the structure, were relatively vibration free but …… it was so mechanically complicated!
Main bearings was in a spherical pocket, and each unit had two pistons and so many bearings; three bottom end bearings in spherical housings, three crosshead bearings and slippers, two side rod bearings and a big centre bearing in the transverse beam.
Despite this, the engines up to 670mm bore seemed to run quite well but, of course, the number of components resulted in a large maintenance load compared with single piston engines even when they were running well.
For my sins most of my time was spent with 75LB6 engines and because I didn’t know much different I didn’t realise at the time how bad they were. I think there were only 12 of this size built and our company had six of them and I sailed on 4 of those.
Before they were 4 years old, all our engines had to have new crankshafts due to a design defect. However, they still had a weakness in that No 3 forward and No 4 aft crankwebs were highly stressed at the internal fillet with the adjacent main journal. This wasn’t helped by the fact that the ships themselves were very flexible and resulted in having to be careful with crankshaft alignment and I became quite proficient at threading a piano wire through the engine and the aft engine room bulkhead to the aft peak bulkhead. However that didn’t stop us finding a large fracture in No.4 on one ship and having carried out a sort of repair sailed back to the UK to discover another fracture at No3 as the engine was being dismantled to receive it’s third crankshaft in 12 years.
All these engines kept the likes of Andrews Master Hones and Golten Marine in business machining our journals and pins in situ as we had numerous bearing failures. For reasons I can’t remember we has several failures of bottom end bearings resulting from the white metal breaking up like crazy paving. Other failures probably resulted from locked sphericals and dirt and water contaminated lube oil.
Being non-diaphragm engines it was a battle to keep the oil clean, not helped by high piston ring and liner wear rates, so we fitted larger bottom piston scraper drains and run purifiers continuously and injected trisodiumphosphate to decrease the acidity .
Water contamination was a problem because the bottom piston cooling water system, in addition to the usual gland problems, also suffered for severe erosion and despite setting off with lots of elbows and pipes, there never seem to be enough.
As a consequence of dirty, wet oil we ended up with a very severe microbial attack on one ship and a lesser attack on another that resulted in more profits for the in situ machiners and the airlines flying crosshead pins back to the UK for microfinishing.
This size engine also seemed to suffer for disproportionally high were rates with the transverse pin bearings compare with the smaller bore engines. I wonder if this had anything to do with the exceptional flexibility of the crankshaft? We had a good example of this with the engine with the fractured crasnkshaft; a large steel strap has been fitted around the crankweb and we had to cut a bit of the bedplate away to allow it to rotate. However when we started the engine we found the strap was fouling the bedplate despite there being ample clearance in the static condition!
There were many more issues but I don’t remember feeling bad about them – in my ignorance I just thought that was the way of things when you went to sea as an engineer in the '60s. But then I did my “steam time”………….. and my eyes were opened!
 

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I had thought that the majority of my sea time was spent with LB Doxfords but looking back into my discharge book I realise that was not the case – it just seemed that way ‘cos lots of “stuff” happen during those times!
The Doxford engine, with its uniflow scavenging and constant pressure fuel injection, certainly had the best fuel consumption of its time and, with no combustion loads transmitted to the structure, were relatively vibration free but …… it was so mechanically complicated!
Main bearings was in a spherical pocket, and each unit had two pistons and so many bearings; three bottom end bearings in spherical housings, three crosshead bearings and slippers, two side rod bearings and a big centre bearing in the transverse beam.
Despite this, the engines up to 670mm bore seemed to run quite well but, of course, the number of components resulted in a large maintenance load compared with single piston engines even when they were running well.
For my sins most of my time was spent with 75LB6 engines and because I didn’t know much different I didn’t realise at the time how bad they were. I think there were only 12 of this size built and our company had six of them and I sailed on 4 of those.
Before they were 4 years old, all our engines had to have new crankshafts due to a design defect. However, they still had a weakness in that No 3 forward and No 4 aft crankwebs were highly stressed at the internal fillet with the adjacent main journal. This wasn’t helped by the fact that the ships themselves were very flexible and resulted in having to be careful with crankshaft alignment and I became quite proficient at threading a piano wire through the engine and the aft engine room bulkhead to the aft peak bulkhead. However that didn’t stop us finding a large fracture in No.4 on one ship and having carried out a sort of repair sailed back to the UK to discover another fracture at No3 as the engine was being dismantled to receive it’s third crankshaft in 12 years.
All these engines kept the likes of Andrews Master Hones and Golten Marine in business machining our journals and pins in situ as we had numerous bearing failures. For reasons I can’t remember we has several failures of bottom end bearings resulting from the white metal breaking up like crazy paving. Other failures probably resulted from locked sphericals and dirt and water contaminated lube oil.
Being non-diaphragm engines it was a battle to keep the oil clean, not helped by high piston ring and liner wear rates, so we fitted larger bottom piston scraper drains and run purifiers continuously and injected trisodiumphosphate to decrease the acidity .
Water contamination was a problem because the bottom piston cooling water system, in addition to the usual gland problems, also suffered for severe erosion and despite setting off with lots of elbows and pipes, there never seem to be enough.
As a consequence of dirty, wet oil we ended up with a very severe microbial attack on one ship and a lesser attack on another that resulted in more profits for the in situ machiners and the airlines flying crosshead pins back to the UK for microfinishing.
This size engine also seemed to suffer for disproportionally high were rates with the transverse pin bearings compare with the smaller bore engines. I wonder if this had anything to do with the exceptional flexibility of the crankshaft? We had a good example of this with the engine with the fractured crasnkshaft; a large steel strap has been fitted around the crankweb and we had to cut a bit of the bedplate away to allow it to rotate. However when we started the engine we found the strap was fouling the bedplate despite there being ample clearance in the static condition!
There were many more issues but I don’t remember feeling bad about them – in my ignorance I just thought that was the way of things when you went to sea as an engineer in the '60s. But then I did my “steam time”………….. and my eyes were opened!
Tim
Would you be talking about the Ripon class when you say the company had 6.
I did 3 trips as Cadet in the Ripon and first trip Third Mate in her.

Alan
 

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Discussion Starter #5
Tim
Would you be talking about the Ripon class when you say the company had 6.
I did 3 trips as Cadet in the Ripon and first trip Third Mate in her.

Alan
Yes Alan, it was that class and she was my first 75LB6 Doxford. I sailed as Engineer Cadet on her in 1962 (my God , that's over half a century ago!). Apart from a 24 hours stoppage in the Red Sea I don't recall much else about her although I have this silly idea that the GA drawing in the alleyway said the funnel was 49'10" high . Could that possibly be true ?!
Next up was the ' Newcastle, my first 2/E job and not many fond memories of her and certainly none regarding trying to sort out a serious problem with No.4 main bearing prior to her being sold to Ben Line in 1968.
That was soon followed by the fateful trip on the 'Colombo when we found the crankshaft fractured and I subsequently stood-by her in Sunderland whilst the the crankshaft was being replaced.
My first C/E job was the 'Winnipeg of which I have few memories but I have many memories of my last trips to sea - back to the dreaded 'Colombo for a couple Canada - India trips.
The class association didn't end there as I had the 'Colombo & 'Newcastle as two of my ships as a Superintendent. It seems that, like the poor, they are always with you (A)
 

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Discussion Starter #6
..... I think there were only 12 of this size built and our company had six of them and I sailed on 4 of those..... [/QUOTE said:
I'm may be wrong about there being only 12 built as, in addition to the ones I knew about, a friend of my mine told me the other day that he was almost certain NZS had some. Can anyone confirm that ?
 

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Interesting stuff, takes me back to my Elder Dempster days over fifty years ago, nearly all Doxfords with the odd one or two B&W's. I have just been looking at the old Port Sydney on YouTube but I cannot remember what the small wheel was for on the left of the controls!! Time to book into the Old Peoples Home I think!!
Can anyone refresh an old brain??
Cheers
Cliff
 

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Interesting stuff, takes me back to my Elder Dempster days over fifty years ago, nearly all Doxfords with the odd one or two B&W's. I have just been looking at the old Port Sydney on YouTube but I cannot remember what the small wheel was for on the left of the controls!! Time to book into the Old Peoples Home I think!!
Can anyone refresh an old brain??
Cheers
Cliff
Fuel pressure, after starting you had to keep fuel pressure up at 600 psi range.
Dannic.
 

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I had thought that the majority of my sea time was spent with LB Doxfords but looking back into my discharge book I realise that was not the case – it just seemed that way ‘cos lots of “stuff” happen during those times!
The Doxford engine, with its uniflow scavenging and constant pressure fuel injection, certainly had the best fuel consumption of its time and, with no combustion loads transmitted to the structure, were relatively vibration free but …… it was so mechanically complicated!
Main bearings was in a spherical pocket, and each unit had two pistons and so many bearings; three bottom end bearings in spherical housings, three crosshead bearings and slippers, two side rod bearings and a big centre bearing in the transverse beam.
Despite this, the engines up to 670mm bore seemed to run quite well but, of course, the number of components resulted in a large maintenance load compared with single piston engines even when they were running well.
For my sins most of my time was spent with 75LB6 engines and because I didn’t know much different I didn’t realise at the time how bad they were. I think there were only 12 of this size built and our company had six of them and I sailed on 4 of those.
Before they were 4 years old, all our engines had to have new crankshafts due to a design defect. However, they still had a weakness in that No 3 forward and No 4 aft crankwebs were highly stressed at the internal fillet with the adjacent main journal. This wasn’t helped by the fact that the ships themselves were very flexible and resulted in having to be careful with crankshaft alignment and I became quite proficient at threading a piano wire through the engine and the aft engine room bulkhead to the aft peak bulkhead. However that didn’t stop us finding a large fracture in No.4 on one ship and having carried out a sort of repair sailed back to the UK to discover another fracture at No3 as the engine was being dismantled to receive it’s third crankshaft in 12 years.
All these engines kept the likes of Andrews Master Hones and Golten Marine in business machining our journals and pins in situ as we had numerous bearing failures. For reasons I can’t remember we has several failures of bottom end bearings resulting from the white metal breaking up like crazy paving. Other failures probably resulted from locked sphericals and dirt and water contaminated lube oil.
Being non-diaphragm engines it was a battle to keep the oil clean, not helped by high piston ring and liner wear rates, so we fitted larger bottom piston scraper drains and run purifiers continuously and injected trisodiumphosphate to decrease the acidity .
Water contamination was a problem because the bottom piston cooling water system, in addition to the usual gland problems, also suffered for severe erosion and despite setting off with lots of elbows and pipes, there never seem to be enough.
As a consequence of dirty, wet oil we ended up with a very severe microbial attack on one ship and a lesser attack on another that resulted in more profits for the in situ machiners and the airlines flying crosshead pins back to the UK for microfinishing.
This size engine also seemed to suffer for disproportionally high were rates with the transverse pin bearings compare with the smaller bore engines. I wonder if this had anything to do with the exceptional flexibility of the crankshaft? We had a good example of this with the engine with the fractured crasnkshaft; a large steel strap has been fitted around the crankweb and we had to cut a bit of the bedplate away to allow it to rotate. However when we started the engine we found the strap was fouling the bedplate despite there being ample clearance in the static condition!
There were many more issues but I don’t remember feeling bad about them – in my ignorance I just thought that was the way of things when you went to sea as an engineer in the '60s. But then I did my “steam time”………….. and my eyes were opened!
Trisodiumphosphate? we used that as cooling water treatment!!
Dannic.
 

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Trisodium phosphate , a strong alkaline has many uses , even in some food stuffs , but we used it at Babcock as a initial boil out additive to the boiler water when first firing after construction to ensure all heat exchange surfaces were absolutely clear of any contamination especially grease and oil etc .
Came the day when we were commissions a new packaged Steambloc fire tube boiler at the Air New Zealand workshops at Auckland airport.
The burner cut out had been set to shut off the fire at just above 50 lbs/sq inch
But the fact was that the steam safety valve, normally tested and set at 155 Psi was slackened back to about 45 psi.
Bang off she went spraying highly corrosive steam and water over the staff car park. Thank God for an easterly wind , had it been a prevailing westerly we would have doused a whole Douglas DC10 over its aluminium hull which might have desolved before our eyes.
Insurance covered us but the payout was huge as every man and his dog made a claim for even the slightest damage to their cars,
The one I fell sorry for was the young typist with a brand new pumpkin coloured Fiat 500, the body work paint was right off.
Well Off thread but a memory brought on by Doxford stories!

Bob
 

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Discussion Starter #14
Trisodiumphosphate? we used that as cooling water treatment!!
Dannic.
Interestingly, we also found that the TSP injection considerably increase the amount of crap removed by the centrifuges
 

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Trisodium phosphate , a strong alkaline has many uses , even in some food stuffs , but we used it at Babcock as a initial boil out additive to the boiler water when first firing after construction to ensure all heat exchange surfaces were absolutely clear of any contamination especially grease and oil etc .
The one I fell sorry for was the young typist with a brand new pumpkin coloured Fiat 500, the body work paint was right off.

Bob
As Sub Ltn't Phillips would have said, " Oooooo Narsty" ' Left hand down a bit '.

Just looked up in my copy of Southern's Marine Oil Engines,
during manoevring keep pressure at 6000lb/ in 2, never let fall below 4000 psi.

That TSP gave a yellow tinge to the cooling water on our ships.
 

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I seem to remember the mechanical fuel injectors, the type with the cage over the nozzle assembly.
They would regularly jam open when the engine was stopped and fuel pressure 6000psi to zero instantly. Then an Engineer running round the middles with the fork to close and isolate the defective injector. Sometimes the relief valve would lift at next start due to fuel in the cylinder.
All in all not my favourite engine.
My last ship was a Wartsila Rt.Flex and they have gone to common rail with a large fuel ac***ulator but no priming pump.
 

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Was the yellow stuff not Potassium Chromate? IIRC you were not meant to use it in systems with a jacket evaporator for potable water as it was poisonous. I only used Nitrate based ones, but the Chromate was also used as an indicator in Nitrate titrations for Chloride contamination.
 

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I seem to remember the mechanical fuel injectors, the type with the cage over the nozzle assembly.
They would regularly jam open when the engine was stopped and fuel pressure 6000psi to zero instantly. Then an Engineer running round the middles with the fork to close and isolate the defective injector. Sometimes the relief valve would lift at next start due to fuel in the cylinder.
All in all not my favourite engine.
My last ship was a Wartsila Rt.Flex and they have gone to common rail with a large fuel ac***ulator but no priming pump.
Would that be AB Dobbie, known for scooping up 45 gallon of HFO and pouring it down a fuel vent, that suddenly appeared overnight as deck cargo on a former Strick Line ship known for these antics because of a design fault, circa 1982.
 

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Potassium Chromate , sounds familiar as well, could well have been that. Nasty stuff. The slight leaks at pump glands would crystalise to a white greenish deposit due to the copper parts in the system.

Did anybody use that Shell oil like cutting fluid used in cooling systems that when mixed with lube oil turned to a grey sludge when coming out the LOP. I was on an MAN 1956 vintage that used it.
Flying Bedsteads had the best idea, oil cooled top and bottom pistons on telescopics, any leak into the crankcase didn't matter.
The slight downside was in high sea temps you needed both oil pumps on to increase circulation, but no big deal.
 

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Would that be AB Dobbie, known for scooping up 45 gallon of HFO and pouring it down a fuel vent, that suddenly appeared overnight as deck cargo on a former Strick Line ship known for these antics because of a design fault, circa 1982.
Former Strick Line ship???
Fuel oil on deck??? unheard off.
 
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