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Doxford Engines 3-legged

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  #51  
Old 4th October 2012, 19:41
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I was going to let that one slide, but as well as the issues that you raise Ian as the rpm increase the propellor efficiency starts to fall due to the effects of cavitation etc, whilst these can be alleviated by the use of tandem propellors the overall efficiency of conversion of potential chemical energy in the fuel to propulsive effort will fall. For most shipowners (warships being a notable exception) the overall plant efficiency for a given service speed is a prime concern. Also increasing RPM markedly will have considerable inertial effects which can be overcome by reducing cylinder diameter and increasing cylinder numbers which quite nicely brings us back where we started.
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  #52  
Old 4th October 2012, 21:02
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Quote:
Originally Posted by chadburn View Post
I have served on a Post War 3 cy unit which was in the Egton, however, the pre War 3cy was (barring for the Scott-Still) one of the most highly rated Marine Engine's available at a mechanical efficiency at about 82% other's being around 73%
EGTON'38 SR(RUNSWICK/GLAISDALE Doxford "Economy")
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  #53  
Old 16th October 2012, 00:34
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Quote:
Originally Posted by Chillytoes View Post
How about this 3-legger? And everything goes around as it should!

http://oi52.tinypic.com/2v0muyd.jpg
wow nice, where was this
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  #54  
Old 17th October 2012, 09:49
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3 -Legged Doxford's

* Wilton Fijenoord, Schiedam, Holland
(3 Legged for French Wine Tanker "BACCHUS"

* 3 Legged, Old Timer, during WWII

All 3-Legged without "Starting Assister" !!!!

Regards
Alfons
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File Type: jpg WFDOXFORD.jpg (129.5 KB, 89 views)
File Type: jpg Doxford002.jpg (101.6 KB, 77 views)
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  #55  
Old 18th October 2012, 17:00
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Quote:
Originally Posted by XFullFatTim View Post
I sailed as 2nd Mate and Chief Officer on 5 ships operated by Ellerman City Liners from 1981 though to 1988 that had the last Doxford 3 legged engines built. They weren't terribly reliable but once started they ran beautifully smoothly. The unreliablity was on the starting and stopping but this was resolved with some major redesigning of the liners and piston crowns of the City of Oxford that transformed the engine's manoeuvrability. Part of the starting problem was a "dead band" detector that soemtime didn't detect that all 3 units were "in line" and the start assister didn't engage to give the engine a half a turn by hydraulic ram............. IIRC
L.S (XFullFatTim;624748)
I am curious to know, what means exact the major redesigning of liners and pistons crowns which transformed in better manoeuvrability?
According DOXFORD the starting assiter was only necessary 1 in 100 times starting?
This was find out on the testbed, perhaps in reality it was different?
Awaiting your answer
Kind regards
ALFONS
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  #56  
Old 5th November 2012, 18:51
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Quote:
Originally Posted by averheijden View Post
L.S (XFullFatTim;624748)
I am curious to know, what means exact the major redesigning of liners and pistons crowns which transformed in better manoeuvrability?
According DOXFORD the starting assiter was only necessary 1 in 100 times starting?
This was find out on the testbed, perhaps in reality it was different?
Awaiting your answer
Kind regards
ALFONS
The piston and liner mods were to improve the compression, particularly when starting astern as there was a lead on the exhaust piston which made starting sometime a bit of a lottery with a bit of liner and piston ring wear!
I think the starting assister may have eventually been removed after a particularly exciting moment when it engaged on one ship when the engine was running at full speed
I seem to recally that the frequency of "dead band" stops was much reduced when we changed the phasing of the propeller in relation to the crankshaft
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  #57  
Old 8th November 2012, 11:00
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There is lots of interesting general Doxford stuff at www.doxford-engine.com
They have sent me lots of pics and meeting notes - quite poignant for me having been involved with the Js, JSs and, for my sins, the LBs. I must have been a very bad boy in my youth
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  #58  
Old 31st December 2012, 11:08
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L.S.
I never sailed with a 3-Legged, so I like to know, was that normal on a 3-Legged Doxford that you had 2 Spare Cylinder Liners on board?
That look much to me.

A HAPY NEW YEAR TO ALL THE DOXFORD LOVERS

Alfons
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File Type: jpg Spare Cylinder liners mv BELA.jpg (52.7 KB, 111 views)
File Type: jpg Ggevens Shell Tanker BELA.jpg (46.0 KB, 33 views)
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  #59  
Old 31st December 2012, 15:17
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Quote:
Originally Posted by averheijden View Post
L.S.
I never sailed with a 3-Legged, so I like to know, was that normal on a 3-Legged Doxford that you had 2 Spare Cylinder Liners on board?
That look much to me.

A HAPY NEW YEAR TO ALL THE DOXFORD LOVERS

Alfons
Certainly on the 58JS3s we only designed the ships to carry 1 spare liner but I seem to recall City of Bristol (2 x 60[?]LB3) that there were "quite a few" although I' not sure why as she ran on diesel and the wear rates were very low. However I think in her early days she had a few liners crack.
Someone was asking about the 58JS3s having the starting assister when the old LB3 didn't - I think that was 'cos the LBs had side cranks at 180 degrees to the main crank but all the turbo charged engines had the side cranks leading by about 8 degrees
B R
Tim G
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  #60  
Old 1st January 2013, 23:54
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I sailed on a four cyl Doxford which carried four spare liners, which did not inspire confidence.
Curiously, it carried only one of each top and bottom pistons.
I think that some companies used their ships as a sort of a spare gear store.

The picture in #58 does not appear to be a three legger. Looks suspiciously like a centre scavenge at top of picture.

Happy New Year

Derek

Last edited by eldersuk; 1st January 2013 at 23:56..
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  #61  
Old 2nd January 2013, 10:12
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Quote:
Originally Posted by eldersuk View Post
The picture in #58 does not appear to be a three legger. Looks suspiciously like a centre scavenge at top of picture.
Derek
Derek,
That is exactly what I thougt too, so I mailed this person for an explanation, but no answer yet
Although, this picture from the same ship (Shell Tanker mv BELA) looks like there are 3 starting air valves.
And I believe - I am not sure -, but you must know, that on a 4 cylinder there were 2 sets of 2 starting air valves?
Regards
Alfons
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File Type: jpg MV BELA Camshaft and Fuel Valve.jpg (187.2 KB, 99 views)
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  #62  
Old 2nd January 2013, 11:02
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I think Derek is confusing the prefabricated Top-Hat of which they are two in shot instead of the usual cast-steel T.H. and look similar to the scavange pump cowling.
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  #63  
Old 2nd January 2013, 23:43
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The way I see it, the bottom one in the pic is the usual cast aluminium bottle guide cover while the top one is a fabricated scavenge pump cover.

I must admit I am stumped by the pic of the three air start valves which indicate a three legger. Did any of them have a mushroom scav pump?
I never sailed on one.

Derek
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  #64  
Old 3rd January 2013, 10:08
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L.S.
I got this answer
"Hi Alfons

Yes that is the top of the scavenge pump which was on the back of the
engine behind number 2 cylinder. The seawater, fresh cooling water and
lubricating oil pumps were directly below, all driven by a rocker arm
from #2 cylinder cross-head. When I started with Shell as a fifth
engineer, I sailed fron New Zealand to Singapore as a passenger on a
Nowegian tanker. It was fitted with a six cylinder Doxford with the
scavenge pump between four and five.

The "B"s were unique in the Shell fleet. They were the only Doxford
engined ships although I understand that there were some equiped with
Doxfords later on when Doxford went onto HVF. All other motor ships in
the Shell fleet ran on HVF but the fuel valves fitted to the Doxfords at
that time wouldn't allow it. Personally I was pleased. HVF wasn't much
fun for the engineers. We had a lot of problems on a Harland and Wolf,
B&W copy, that I sailed on.

I didn't think about it at the time, but in retrospect, 2 spare liners
is a bit much but that's what was supplied. I doubt if they were ever
used. We did a re-ring on number two cylinder and the bore was in good
condition.

Using my images will be fine. Would yu like me to email higher
resolution copies?

Regards

Derek

( I found a picture on Internet concerning the mv Bela Engine Room, I enlarged it and give the Engine a color, so it is indeed a 3-Legged)
Regards
Alfons
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File Type: jpg ER BELA.jpg (26.2 KB, 79 views)
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  #65  
Old 3rd January 2013, 11:35
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The 3cyl. only had a side lever scavenge pump and were in the middles and could not be seen from the tops(as in the photo).The photo. shows the back of the engine tops(no hoses and protection covers).So the mystery deepens.(Center scavenge pump cowlings are much higher than the tops).
BELA /BORUS were a Empire "Intermediate" type.sisters EMPIRE COMMERCE,EMPIRE GAIN (BARBATIA),EMPIRE RUSSELL (BATISSA),EMPIRE CREST (BURSA),EMPIRE CROSS (BALEA),EMPIRE MALDEN (IMPERIAL HALIFAX),EMPIRE GANGES (BOLMA)(AUSTRALITY),EMPIRE ENSIGN (BRITISH DRUMMER),EMPIRE ARROW(BRITISH BUGLER),EMPIRE SENLAC (BULLINA)

Attachment 32478 Attachment 32480

Last edited by A.D.FROST; 18th July 2013 at 18:24..
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  #66  
Old 4th January 2013, 09:56
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Quote:
Originally Posted by A.D.FROST View Post
The 3cyl. only had a side lever scavenge pump and were in the middles and could not be seen from the tops(as in the photo).The photo. shows the back of the engine tops(no hoses and protection covers).So the mystery deepens.(Center scavenge pump cowlings are much higher than the tops).
A.D.F and other readers
I fully agree with your sight on the situation
So I asked Derek again, with a sketch, where I showed the direction of the yoke (transverse beam) in red, that it was NOT a Lever Driven Scav. pump.
Here was his answer:

Hi Alfons

The Bela had the lever type scavange pump. The six cylinder Norwegien Doxford had the crank driven pump. The Bela engine was basically laid out as shown. I think that the perspective in the photo is confusing. The top of the pump was lower than it appears. Unfortunately the old photographs are beginning to fade and are not in very good condition now.

I'm not certain about the horsepower but I think that it was around 3000. I could be wrong though. It was almost 60 years ago. I remember that it was similar to the much larger six cylinder B&W four stroke. Much against my wishes I had to give up the sea after 2 1/2 years because my father wanted me to help him start up a Motor and General Engineering business.
Regards
Derek


I give up now!
Regards
Alfons
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  #67  
Old 19th April 2013, 16:03
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Quote:
Originally Posted by demodocus View Post
There was a 3 cylinder Doxford on at least 1 of the following China Nav. ships ..... Shansi, Soochow, Szechuan, Sinkiang all built UK 1945/46
L.S.

DOXFORD ENGINES: China Navigation Co and TAIKOO built DOXFORD's

http://users.telenet.be/doxford-matt...20HONGKONG.pdf

Regards
ALFONS

Last edited by averheijden; 19th April 2013 at 16:08..
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  #68  
Old 19th April 2013, 17:53
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Originally Posted by averheijden View Post
L.S.

DOXFORD ENGINES: China Navigation Co and TAIKOO built DOXFORD's

http://users.telenet.be/doxford-matt...20HONGKONG.pdf

Regards
ALFONS
YUNNAN, YOCHOW 670LB5 and NINGHAI 670LB6

Last edited by A.D.FROST; 19th April 2013 at 18:04..
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  #69  
Old 19th April 2013, 19:16
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YUNNAN, YOCHOW 670LB5 and NINGHAI 670LB6
Thanks Tony, soon I will add it to the list
Alfons
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  #70  
Old 16th October 2013, 07:57
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Alfons asked:
Who can tell more about his experience with the starting assister?

I was on the builder's sea trials of the "City Of Plymouth" out of Appledore Shipbuilders and I believe the problem with the over-enthusiastic dead-band assister occurred during that trial. I can't supply much detail as I kept out of the way, it seemed to me that the Doxford men had enough on their plates without me poking my nose in as well.

I thought it best to concentrate on the Blackstone generators that I was there to look after, but I seem to remember they had quite a bit of bother with flexible pipes failing and covering the job in oil prior to the big bang. The engine was a 58JS2, I believe.
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  #71  
Old 16th October 2013, 10:27
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http://www.wikiswire.com/wiki/Soochow_III
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  #72  
Old 24th October 2013, 22:54
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Was the Doxford engines built under licence by John Lewis fitted in the Lammermuir and a coaster and those from Ailsa three cyl?
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  #73  
Old 24th October 2013, 23:04
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Quote:
Originally Posted by japottinger View Post
Was the Doxford engines built under licence by John Lewis fitted in the Lammermuir and a coaster and those from Ailsa three cyl?
Just checked
Lammermuir Eng no284 Not sure this engine was not actually built by Doxford
Trials 12 June 1950.
3 Cly, dia 440mm combined stroke 1440mm
Scavenge pump bore 1250mm x 387 stroke
At 950bhp speed 12.63 knots
At 1030 BHP 13.33 knots
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  #74  
Old 25th October 2013, 00:25
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I have posted copies in the Gallery, taken from the Motorship November 1949 which gives a good account of the engine. Built by Doxford and the ship towed to Sunderland for the installation.
I have a little more information if anyone is interested. Thanks to John ( Jack ) Jordan, who kindly gave me this information
Hamish
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  #75  
Old 25th October 2013, 09:44
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J.Lewis and Alisa had licenses to build baby Doxfords(medium speed)
(Lew.BEN LUI,CARDIFFBROOK,SOLON)(Ala.CENTURY,NOUTHUMBRIAN PRINCE,RONA,WARRING)
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