# The Doxford Nemstop



## Jocko (Oct 31, 2011)

I`m almost certain that it was on the Doxford engine where we had a third lever on the controls called Nemstop.
To stop the engine faster this lever opened the air injection valves and stopped the engine in half the time.
Obviously emstop is Emergency Stop but what I want to know is what did the N stand for? I hope I got the details correct but it`s been a long, long time since I stood on the plates.


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## Jocko (Oct 31, 2011)

Sorry I think I got that wrong. Didn`t it inject air into the rising pistons to act as a brake?
If I didn`t hit it I staggered it!!!!


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## bill mc guire (Jun 10, 2010)

my only experiancr with doxfords was on aj type and a l/b and if you tried to stop them with air injection you only made them turn faster


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## hamishb (Oct 23, 2008)

Jocko said:


> I`m almost certain that it was on the Doxford engine where we had a third lever on the controls called Nemstop.
> To stop the engine faster this lever opened the air injection valves and stopped the engine in half the time.
> Obviously emstop is Emergency Stop but what I want to know is what did the N stand for? I hope I got the details correct but it`s been a long, long time since I stood on the plates.


Hi, I am fairly sure that the NEM stop was a modification used by North Eastern Marine Company. Alfons will have more info on the subject.
Regards
Hamish


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## Jocko (Oct 31, 2011)

Thanks Hamish, I`ll settle for North Eastern Marine.
I`ve only been with Ships Nostalgia for a couple off months but this is what does. It brings back lots of things long forgotten. Pure magic.


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## Mike S (Dec 27, 2005)

Ah memories..........North Eastern Marine.......nemstop......
At the time I saw one in operation on the MV Rosetti while on trials in 1956 it was fitted to a 5 cyl Doxford. My dear long departed father was the MD of NEM at the time and I was able to go on the trials. Jackie Stevens was outside manager at NEM then and he was on the controls and it did work well. How I am not sure although I seem to recall something about it opening ports in the cylinder. 
Jackie (Mr Stevens to all other than his closest) was heard to say that "The Doxford was the closest thing to perpetual motion that man ever made!" 
He was also the holder of the most starts record when they did the starting tests on trials. He gave a wee demo on that trip and I think they lost count somewhere in the forties and the Bridge rang down and said "OK can we go now!"
There were some larger than life characters around that river then.


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## stores (Apr 8, 2007)

*re doxfords*

hi. would that rosetti be the woodford on charter from watts watts, ?


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## Jocko (Oct 31, 2011)

I`m not sure what you mean by 40 starts Mike? Did that not include stops etc. The reason I ask is that I was on the controls of a Doxford, with Nemstop lucky enough. We were docking in New Zealand, it might have been Port Chalmers, my memory is a bit hazy. Anyway we had a kamikaze Pilot on the bridge and he placed us alongside between two other ships. He managed to shear off the flagpole plus flag of the ship forward of us with our bow.
I distinctly remember that we had an amazing 56 movements in our log and we were quite chuffed with ourselves with the poor Compressor running like crazy.
I don`t recall how they patched up relations with the other ship but we had a great time that night talking about it accompanied with a large amount of grog.


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## Ian J. Huckin (Sep 27, 2008)

Jocko said:


> I`m not sure what you mean by 40 starts Mike? Did that not include stops etc. The reason I ask is that I was on the controls of a Doxford, with Nemstop lucky enough. We were docking in New Zealand, it might have been Port Chalmers, my memory is a bit hazy. Anyway we had a kamikaze Pilot on the bridge and he placed us alongside between two other ships. He managed to shear off the flagpole plus flag of the ship forward of us with our bow.
> I distinctly remember that we had an amazing 56 movements in our log and we were quite chuffed with ourselves with the poor Compressor running like crazy.
> I don`t recall how they patched up relations with the other ship but we had a great time that night talking about it accompanied with a large amount of grog.


40 starts with the air comps off. i.e. 40 starts out of the start air receiver(s) without them topping up at the same time.


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## ted harrison (Oct 16, 2009)

*newmstop*

Yes, it was a pattent of the North Eastern Marine Engineering Co. Ltd of Wallsend on Tyne.
The Common Bros IRON ORE had the device fitted and the 2/e in 1960 (Billy Newton from Sunderland) tried it out successfully. It's long time ago but I think the action of the nemstop was to introduce compressed air into the converging pistons (ie, the opposite to the staring action which of course blows them apart)
It was a very effective device.
The ''stops & starts'' were a (Lloyds) performance requirement where alternate 12 ahead and 12 astern movements from a full receiver with it's inlet valves shut off. 24 such movements could be a bit of challenge to the un-initiated but in the hands of the likes of Jack Stevens, it was made to look easy.
There is a picture of the 'nemstop' in our gallery.
Happy Days


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## Jocko (Oct 31, 2011)

Thanks Ian, That is truly is a lot of starts from one Air Receiver. If I had been asked that question I would probably have guessed about 12. You learn something everyday.


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## eldersuk (Oct 24, 2005)

I sailed on a Nemstop Doxford many years ago. My (often unreliable) memory seems to tell me that this gadget opened the cylinder relief valves in a sequence that put the engine seriously out of balance, thus causing it to give up the struggle and stop. I know the Chief put a complete ban on its use except in emergency, which is probably why we ran into the quay in Bergen.

Derek


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## Mike S (Dec 27, 2005)

The Rosetti was a new build at the time I think for Lamport & Holts but hell it was a very long time ago.


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## Jocko (Oct 31, 2011)

Hello Eldersuk, What was the problem with that chief restricting the use of the Nemstop.? As I recall we used it anytime you got a double ring on the telegraph which was almost all the time.
God I loved docking when you could put your big powerful engines to use and knowing that when you got "Finished with Engines" you were going to get showered and head ashore for a piss up with some very good mates.
We are lucky to have memories like that, even to this day I pity those who never ventured away from their birthplace.


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## Jocko (Oct 31, 2011)

I`ve just watched a Doxford Seahorse running on the S/N TV channel. It seemed to be running awful fast almost like a wee generator. The controls were like nothing I would ever remember and all covered in a drab steel casing. It seems like the days of beautiful gleaming brass and copper pipes have disappeared.
Strangely enough the engineer looked awful clean, spotless in fact.


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## eldersuk (Oct 24, 2005)

_What was the problem of that chief restricting the use of the Nemstop?_

He had a thing about cyl relief valves. Anyone who lifted one had to remove it and o/haul it at the first opportunity.

Derek


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## Mike S (Dec 27, 2005)

My old Uncle Ronnie Smith C/E in Headlams (I think.......Runswick Bay was one ship) used to joke that the best way to test a relief valve was to lift it. He was sailing with a Master who was very nervous when within 5 miles of the shore and with the fiddly forward of the funnel on one ship he used to delight in firing off a couple on the first astern movement. The Masters reaction was to run around the bridge wing like a headless chook.
Well that was the story Uncle Ronnie used to tell.........and he did not let the truth get in the way of a good story.


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## Frank Moorhouse (Sep 19, 2010)

*Doxford Nemstop*

I personally Have never heard of the Nemstop but on E D's Aureol there was a button on the controls which allowed the operation of a brake on the propshaft. I believe the instruction was not to be used above 30 RPM.


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## Derek Roger (Feb 19, 2005)

The Doxfords being 2 stoke engines did not have any valves ; therefore the only way to slow the engine down after the fuel was shut off was to introduce starting air to the cylinders ; timed out of phase with the normal starting air sequence ; so that the air into the cylinders caused the engine to slow down . This was the Nemstop .

Dont know what is so difficult to understand .

On a Sulzer ; 7 RD 760 ; the same effect could be obtained ; shut off the fuel ; put the telegraph to astern and wait until the servo clicked into astern then apply starting air . The air ( trying to start astern ) would very quickley slow down the engine and eventually start it to run astern ( used a lot of air but was only for use in emergencies )

Must check my diagram of the Mahout system of control to see if this function was available when on bridge control . I think perhaps not .

Derek


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## uisdean mor (Sep 4, 2008)

Derek 
Absolutely not available re Mahout system. We had enough trouble with enthusiastic and overly ambitious use of the system. Air usage has been mentioned previously on here. Not sure if multiple firing has been discussed previously whereby an attempt to start ( whether ahead or astern) has not met the pilot's or other navigating panjandurum's expectations and they have decided to "give it another shot" without giving the system enough time to actually do its business. A few relief valves tested that way. Not to mention deck wallahs hearing aids as the blast echoed round the funnel space.
Rgds 
Uisdean


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## JET (Oct 22, 2005)

The quickest way to stop a Doxford - Permanently, is to compress water between a pair of opposed pistons when kicking the engine over on air.

John


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## john g (Feb 22, 2005)

uisdean mor said:


> Derek
> Absolutely not available re Mahout system. We had enough trouble with enthusiastic and overly ambitious use of the system. Air usage has been mentioned previously on here. Not sure if multiple firing has been discussed previously whereby an attempt to start ( whether ahead or astern) has not met the pilot's or other navigating panjandurum's expectations and they have decided to "give it another shot" without giving the system enough time to actually do its business. A few relief valves tested that way. Not to mention deck wallahs hearing aids as the blast echoed round the funnel space.
> Rgds
> Uisdean


We often had to ask the bridge to go easy on the starts as the two Hamworthy compressors were rapidly loosing ground. Can't remember there ever being a problem stopping the Sulzers quickly , would have thought the motion of the vessel would have an effect. Then there was Calcutta manovering into the docks.....hey ho a long time ago.


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## averheijden (Jan 23, 2007)

hamishb said:


> Hi, I am fairly sure that the NEM stop was a modification used by North Eastern Marine Company. Alfons will have more info on the subject.
> Regards
> Hamish


*L.S. (Hamish)

Here is some more information on the NEM-Stop

http://users.telenet.be/doxford-matters/NEM-STOP.html

or:
http://www.shipsnostalgia.com/galle...cpage/39/title/doxford-opposed-piston/cat/525


Regards
Alfons*


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## Malky Glaister (Nov 2, 2008)

Alfons.

Very interesting article. Thanks

regards Malky


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## averheijden (Jan 23, 2007)

JET said:


> The quickest way to stop a Doxford - Permanently, is to compress water between a pair of opposed pistons when kicking the engine over on air.
> 
> John


*For water between the pistons, see the story of the EASTERN ROVER

http://users.telenet.be/doxford-matters/tekst/Re-alignment Eastern Rover.pdf

For more DOXFORD ACCIDENTS see:

http://users.telenet.be/doxford-matters/doxforddamages.html

Regards
Alfons*


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