double acting diesels

BERRIET
21st April 2008, 13:09
Good morning everyone ,

did anyone deal with two stroke , double acting MAN diesel engines? D 8 Z 72/120 type ? with roots blowers ?

thanks for any infos !!(Thumb)

steve2
28th November 2008, 17:04
Similar to the H&W-B&W double actors. The roots blowers were chain driven from the crankshaft. Lots of air used when manoevering from ahead to astern and a great thump when the flap valves in the blowers went across. Reversing the engine also reversed the blowers so the flap valves corrected the flow of scavenge back to the engine.
Wonderful watching these engines in operation, pistons flying everywhere as the upper exhaust pistons were yoked to the lower. When overhauling a unit the top platform was a mess of gear.
Most engines had conventional camshafts, fuel pumps and fuel injectors but some had gas pumps and injectors. (but that's another bag of worms)
Best regards
Steve2

Blackal
30th November 2008, 22:19
Were the H&W engines not "Exhaust Piston" type, rather than true "double-acting"? I seem to remember them as having the exhaust piston coupled to the crankshaft via a crosshead and eccentric, rather than a crank.

Al:)

steve2
28th December 2008, 19:34
Hi Al,
In the H&W engine the lower exhaust piston was strapped to the upper exhaust piston via yokes and driven by excentrics as you say. The main piston between them was driven by the crank. So as there were fuel injectors in the upper and lower compression spaces this made them double actors. Hope I'm making sense!
Best Regards, Steve.

cubpilot
30th December 2008, 14:08
Steve, if i understand you the engine had 3 pistons? if so with the bottom being coupled in some way to the top did this lower piston have the main piston rod passing through it and some form of stuffing box?

I once sailed on an MAN engined ship built immediately after ww2 in denmark. it was loop scavenge with side rods from the crossheads driving scavenge air pumps and also utilised the under piston method with flap valves to increase scavenge air pressure. all very normal but the bug bear with the engine were the stuffing boxes on the piston rods. on each rod there was a main set located at the bottom of the cylinder liner to seal against the scavenge pressure and then a smaller set on the crankcase top to seal the crankcase. the gap between was exposed and you could see the piston rod moving up and down.
the stuffing box rings were cast iron segments and were size matched to the rod diameter. regularly we would get siezed rings and then if the engine was not slowed down promptly the fuel pump on the affected cylinder lifted and liberal quantities of oil squirted onto the rod then in short time the rod would start to build up heat and could become cherry red. highly conducive to a crankcase explosion. if a rod did go red it would also bend. in that case we would end up with a major stoppage and change pistons. the ship carried more than the normal stock of spare piston rods and we became quite adept at rebuilding piston assemblies whilst at sea.

i bet those H&W engines were a nightmare

Archie NS
30th December 2008, 17:07
There's a good description of a Harland & Wolff opposed piston double acting engine by C.C. Pounder. Lots of drawings.

http://www.rakaia.co.uk/downloads/hw-da-engines.pdf

I never sailed on a double acting H&W but plenty of opposed piston ones, somewhere in the far past I was told that the reason H&W went with the eccentrics was due to a patent dispute with Doxfords. This may be a myth I'm not sure

sidsal
30th December 2008, 20:21
Fascinated by you engineer wizards. I was 3rd mate on a tanker F J WOLFE of the Anglo American Oil Co just after ww2. She had twin MAN engines which were rogue engines in all senses of the word. The engineers kept watch in swiming trunks due to the oil squirting everywhere. Most places we called at we stayed a week at least whilst they tinkered with the engines. There have been quite a few Threads about her recently. I joined her in Barrow for 3 months where she had gone as engineers from the MAN works were working there on peroxide propulsion for submarines ( superceded by atomic power). She was just as bad after their attentions. She had sister ships with similar problems and once we rowed over piston rings to one of them in the Arabian Sea where she was wallowing.
Incidentally our Rotary visited a most intersting engine museum at Poynton Cheshire - the Anson Museum. It is on an old colliery site and has lots of old engines which are in working condition. As you chaps probably know, Manchester had about 6 engine builders ) Mirlees, Gardener, Crossley and so forth. Sadly all now gone.
Best wishes
PS Mirlees was taken over by MAN a few years ago - and shut down except for a department maintaining Mirlees engines. The main factory is demolished and office blocks just built there ( all empty of course). Paradoxically, someone told me that they make more money now than they did when building engines. It's a crazy world.
Sid

steve2
31st December 2008, 10:19
G'morning Cubpilot.
Yep- the piston rod for the main piston passed through a stuffing box in the centre of the lower exhaust piston and also through the entablature above the crankcase. The lower exhaust piston had a yoke from which rods went up to the upper exhaust piston, driving it in tandem. Lots to watch on those old engine rooms. There was no underpiston scavageing as this was provided by rooted blowers. As Archie points out- CC Pounder wrote the bible! Unfortunately most of us dummped our copies when the dinosaurs died out!
Sid- Liverpool Nautical mueseum also has a latge collection of working models of various engines built to fit into local built ships. Camel-Lairds even built an engine called the Fulgar(?) Engine where the main piston of one unit drove the exhaust piston of the next. Talk about man's inhumanity to man! I believe that this engine was nicknamed the fullofgear engine.
All the best for the New Year. Steve

david freeman
31st December 2008, 11:00
Good morning everyone ,

did anyone deal with two stroke , double acting MAN diesel engines? D 8 Z 72/120 type ? with roots blowers ?

thanks for any infos !!(Thumb)

Question Were Gotoverken Engines ever produced as a double acting version, if so they must have been quite a joy?

cubpilot
31st December 2008, 13:15
I like the comment that it was a simple engine to overhaul.
i forgot to mention that on that 1946 built MAN if the ship was loaded evenly we had no problem but if any hogging sagging or twist in the hull then we suffered. luckily average passage length was a week and i suspect on a bad passage there were words from the chief to captain.
my other MAN engine experiences on mid 70s built engines were a delight. in 5 years i think we only had one stoppage due to an engine problem when a cam profile broke.

BOB.WHITTAKER
15th November 2009, 23:37
My first ever ship was MV Salamanca , one of PSNC "S" boats,I joined it in Hull whilst she was in drydock. All of the S boats had 8 cylinder double acting B + W main engines,I couldnt believe my eyes the first time I saw the engine run,did a few runs round the land then deep sea on the Somers Isle,she had a 4 cylinder single acting B + W. Then back onto the Salamanca as 4th engineer, the only highlights really were the occasional scavenge fire, the engine though labour intensive(24 pistons,numerous fuel valves, air start valves,relief valves and stuffing boxes) did to my memory anyway seem reasonably reliable.I seem to recall spending more time gassing up the deck fridge containers under the Chiefs (George Hawkins) instruction than anything else .

tugtere
16th November 2009, 02:02
I did a stretch on Nauru Island in the power house in the 1980's. There were two Mirlees, two Fulagar's and a pair of "Crossley-Pielsticks" installed.I was supposed to dismantle the Fulagars for scrap but the new Crossleys were so unreliable(from brand new) that the old girls were retained as standbys.They are probably still there now.They were an amazing thing to watch with bits n pieces jumping up and down.Regards Ray

Philthechill
16th November 2009, 07:13
I doubt if there's anyone old enough on SN to have sailed on White Star's "Brittanic" but I believe her, and her sister-ship ("Olympic"?) had double-acting FOUR strokes!

I'm sure I've seen a picture of one of these engines, somewhere, but I'm not 100% certain.

I seem to remember looking at the forest of push-rods and thinking what a nightmare they must have been for maintenance.

Can anyone confirm whether I'm right---------------or is it time to call for "the-men-in-white-coats"? Salaams, Phil(Hippy)

BOB.WHITTAKER
16th November 2009, 10:24
Double acting fourstrokes ,I never sailed on one but " I know a man that did ". In the late sixties and into the seventies Houlder Brothers had a group of stalwarts who used to cover most of the relieving duties in the U.K. Three of the engineers were Alex (the Silver Fox), Ronnie Angel and Alec Cowderoy . Many a long "smoko" in the duty mess (whilst alongside) was spent with Alec in particular regaling all present with his tales of past engines.He could go back to prewar days and he gave vivid descriptions of sailing on double acting fourstrokes regards the maintenance levels and also their function, allways interesting was his explanation of the mechanisms involved in getting the engine to run astern. These sessions were as informative as any of the E.K. lectures when I did 2nds and Chiefs at South Shields .

chadburn
16th November 2009, 10:54
Not as yet for the white coat's Phil, these engine's were built by B&W. It was considered to be a very important development of the marine diesel, a single cylinder engine was built at their experimental station at Christianshavn which gave a reading of 1,000BHP, it ran day and night for a month and B&W were highly delighted with it. It was of course all to do with poweeeeeeeeeeer. Up till this engine appeared B&W max was 300 BHP per Cylinder, the reason for the building of the double acting for was for the fast Liner market which meant that large fast Liner's could be built with twin engine's at that time without the normal distribution of shaft's and prop's with other forms of propulsion. Never worked on one a bit before my time, I thought Doxford's had way to many extra bits hanging about never mind this engine!!!

Philthechill
16th November 2009, 17:41
First things first, then the nitty-gritty!

Thanks Bob and Geordie Chief for saving me from spending the rest of my days doubting my sanity (however, come to think of it, I do that on a daily basis anyhow!!!).

I said that I thought the ship, with the double-acting four-stroke engines was "Brittanic". I was wrong as she actually had a combination of up-and-downers and turbines.


I found-out, from t'Internet, ( Pounders 8th. Edition), that there were two ships fitted with the B&W four-strokes and they were the Swedish America "Gripsholm", (1925-built), and Union-Castle's "Caernarvon Castle" of 1926. (Incidentally there's very little to be found-out, even from said Internet, about these engines, although having just typed that, I never looked on B&W's site (if they have one) to see if they have a historical section. Memo to self:- Your next task, after submitting this, is to check for a B&W site!!!!).

Now, being as "Caernarvon Castle" wasn't scrapped until 1963 surely there's someone who sailed on her, (who is on this wonderful site), can give us a bit of an insight as to what these engines were like to work on?

Or was the ship re-engined at some time?

Thanks, again, Bob and Geordie Chief. Salaams, Phil(Hippy)

surfaceblow
16th November 2009, 17:55
There is an article on B & W Number 1 at Christianshavn with pictures at the link below. One of the other Dieselfacts is a short movie on the first Diesel Ship I forget which issue but you can have an interesting time looking at the new and old stuff in most issues.

http://www.manbw.com/files/news/filesof6176/Dieselfacts_2007_1.pdf

Joe

hamishb
17th November 2009, 15:47
First things first, then the nitty-gritty!

Thanks Bob and Geordie Chief for saving me from spending the rest of my days doubting my sanity (however, come to think of it, I do that on a daily basis anyhow!!!).

I said that I thought the ship, with the double-acting four-stroke engines was "Brittanic". I was wrong as she actually had a combination of up-and-downers and turbines.


I found-out, from t'Internet, ( Pounders 8th. Edition), that there were two ships fitted with the B&W four-strokes and they were the Swedish America "Gripsholm", (1925-built), and Union-Castle's "Caernarvon Castle" of 1926. (Incidentally there's very little to be found-out, even from said Internet, about these engines, although having just typed that, I never looked on B&W's site (if they have one) to see if they have a historical section. Memo to self:- Your next task, after submitting this, is to check for a B&W site!!!!).

Now, being as "Caernarvon Castle" wasn't scrapped until 1963 surely there's someone who sailed on her, (who is on this wonderful site), can give us a bit of an insight as to what these engines were like to work on?

Or was the ship re-engined at some time?

Thanks, again, Bob and Geordie Chief. Salaams, Phil(Hippy)

Hi Phil, A picture of the Double Acting 4 stroke engines built by Kincaids in the 1920s. The photo shows the dreaded blast compressors on the end of the engine. Quite a lot of these were built, must have been a nightmare to maintain. As an apprentice I worked on spare pistons cylinder covers and other bits for these engines in the 1950s.
Regards
Hamish

chadburn
17th November 2009, 16:22
The thumbnail picture by Hamish is about the same profile as the single cylinder 1923 test engine, unfortunatly I have changed to Vista and I am having difficulties posting photo's as the system will not accept my server for some reason otherwise I would have posted the photo I have from the old B&W house mags which I received when I worked for Maritime O. The companies engine's were mainly B&W and the companies Senior Engineer's were on the mailing list.

Long gone
17th November 2009, 19:11
I have a book in my possession, 'British Ships Illustrated' by A.C. Hardy, published in 1933. The 1929(?) 'Georgic' and 'Britannic' are described.

It says she has 'twin screws each driven by a large Harland-B&W 4-cycle double acting internal combustion engine, each developing about 10,000 horsepower, and the two of them giving the ship at sea a speed of about 18 knots'....Later on it says 'each engine has 10 double-acting cylinders' It doesn't say whether these were O.P. though.

As an aside, The White Star Line seems to have been quite an innovator when it came to engine design, the engine spec. on the previous 'Britannic' being a case in point; the first ships to use an L.P. exhaust turbine in combination with recip. engines.

chadburn
18th November 2009, 11:34
It is also indicates that the new engine may also be built as a long stroke engine for a single screw ship, this being a substitute for the twin screw config on larger cargo and passenger vessel's which may have been formerly provided with B&W short stroke engines with a similiar economy being secured. The new type can be built with power in the region of 5,0000/6,000bhp

Philthechill
18th November 2009, 15:25
Hi Phil, A picture of the Double Acting 4 stroke engines built by Kincaids in the 1920s. The photo shows the dreaded blast compressors on the end of the engine. Quite a lot of these were built, must have been a nightmare to maintain. As an apprentice I worked on spare pistons cylinder covers and other bits for these engines in the 1950s.
Regards
HamishHamish! Thanks very much for putting this picture of the, Kincaid-built engine, on here but I'd already "clocked" the picture in The Gallery and added a couple of comments about it. Salaams, Phil(Hippy)

hamishb
19th November 2009, 19:13
Hamish! Thanks very much for putting this picture of the, Kincaid-built engine, on here but I'd already "clocked" the picture in The Gallery and added a couple of comments about it. Salaams, Phil(Hippy)

Hi Phill, I have posted a picture of a side view of an engine built for Clan Line.
Kincaid built engines, with a few exceptions were built on a B&W sub lisencs from Harland & Wolf.
The 3 camshafts are visible along with the upper pushrods.
I will scan and post a picture of a Single Acting engine of the same era for comparison.

hamishb
19th November 2009, 20:59
Hi Phill, there are enough pictures and some other inieresting info. in the gallery under Clan MacDonald so I won't add another picture.
Single acting engine is in.
Regards
Hamish.

Philthechill
20th November 2009, 17:55
Hi Phill, I have posted a picture of a side view of an engine built for Clan Line.
Kincaid built engines, with a few exceptions were built on a B&W sub lisencs from Harland & Wolf.
The 3 camshafts are visible along with the upper pushrods.
I will scan and post a picture of a Single Acting engine of the same era for comparison.Going astern with such an engine must have been quite an undertaking I would imagine!

The maintenance of a double-acting four-stroke must have been a nightmare what with the numbers of valves to look after! I bet the engineers couldn't believe their luck when double-acting two-strokes became the order-of-the-day. Thanks again Hamish. Salaams, Phil(Hippy)

Billieboy
20th November 2009, 18:38
Going astern with such an engine must have been quite an undertaking I would imagine!

The maintenance of a double-acting four-stroke must have been a nightmare what with the numbers of valves to look after! I bet the engineers couldn't believe their luck when double-acting two-strokes became the order-of-the-day. Thanks again Hamish. Salaams, Phil(Hippy)

This was before the days of hydraulic nuts and bolts, it was all hand hammer work!

ken dag
21st November 2009, 15:36
Copenhagen - 3rd Sunday of month at 11am in Diesel House Museum
8 cyl double acting 2 stroke 840mm bore B&W diesel built in 1932 runs for 10 minutes. (video of engine was on www.dieselhouse.dk)

double acting
30th November 2009, 21:31
A the joys of changing bottom exhaust pistons on the Stirling Castle. She was too large to have chain driven scavenge blowers, hers were independent from the main engine, driven by large electric motors

Peter B
30th November 2009, 22:01
Copenhagen - 3rd Sunday of month at 11am in Diesel House Museum
8 cyl double acting 2 stroke 840mm bore B&W diesel built in 1932 runs for 10 minutes. (video of engine was on www.dieselhouse.dk) (http://www.dieselhouse.dk))
Actually that is 1st and 3rd sunday of month (Thumb)

MWD
2nd December 2009, 11:48
First things first, then the nitty-gritty!

Thanks Bob and Geordie Chief for saving me from spending the rest of my days doubting my sanity (however, come to think of it, I do that on a daily basis anyhow!!!).

I said that I thought the ship, with the double-acting four-stroke engines was "Brittanic". I was wrong as she actually had a combination of up-and-downers and turbines.


I found-out, from t'Internet, ( Pounders 8th. Edition), that there were two ships fitted with the B&W four-strokes and they were the Swedish America "Gripsholm", (1925-built), and Union-Castle's "Caernarvon Castle" of 1926. (Incidentally there's very little to be found-out, even from said Internet, about these engines, although having just typed that, I never looked on B&W's site (if they have one) to see if they have a historical section. Memo to self:- Your next task, after submitting this, is to check for a B&W site!!!!).

Now, being as "Caernarvon Castle" wasn't scrapped until 1963 surely there's someone who sailed on her, (who is on this wonderful site), can give us a bit of an insight as to what these engines were like to work on?

Or was the ship re-engined at some time?

Thanks, again, Bob and Geordie Chief. Salaams, Phil(Hippy)

HI!

I have just checked in Duncan Hawes Merchant Fleets Union Castle edition and it seems the original Winchester Castle of 1929 was double acting 4 stroke, however, re-engined in 1938 with B&W double acting two stroke units to meet the new mail schedules.

Caernarvon of 1926 apparently always had two stroke units.

Two trips in early 50's in Roslin Castle with the B&W double acting exhaust piston two strokes was enough to turn me into a steam engineer!

Hope this helps.

MWD.

Peter B
7th December 2009, 23:08
Video of the engine at Dieselhouse Museum in Copenhagen:
http://www.youtube.com/watch?v=D24EMlA8Bzc&feature=related

MarcelB
8th December 2009, 03:16
Question Were Gotoverken Engines ever produced as a double acting version, if so they must have been quite a joy?

I was an oiler on a ship called the St.Lawrence Prospector and it had a Gotoverken (6 cyl) and believe me it was No Joy.That was back in 1976 and I was only on her for 3 weeks.I don't remember too much about her except that it had scavenge pumps which seemed that every time we where in port we would be hauling them apart.I was very happy to get transferred back to my own ship the Cape Breton Highlander which had a big Harland Wolfe B@W and that was a dream to work on.I also worked on a few ships on the great lakes which had Fairbanks Morse opposed piston engines.They either had 4 x 8 cyl. or 4 x 10 cyl engines.Their main problem was if you didn't burn marine gas oil in them and used a lower grade of diesel fuel you where constanly cleaning the exhaust ports on them.Every winter during the layup period Jan-March you would overhaul 2 of the 4 One winter it would be #1 and 2 and the next winter #3 and 4.(Hippy) (Hippy) (Jester) (Jester)

Pampas
14th December 2009, 17:17
Full away Xmas eve 1963, hauled out of scratcher by one rather "pIE-EYED" 2nd "Lecky" here crack this lot asap. armed with an alloy coat hanger and a bag of Wallnuts to crack between the rather flexible units, didnt take long to do either and only lost a couple in the process. I bet H&w didnt think of alternative uses for their engines!!!
The Utube of the engine is of I think one that was built around 1936 and is now preserved and is also used as a standby generator. RML ships as far as I recall all had B&W`s fitted most 6 Cylinders some 4 and the three A boat had twin 8 cylinders. The noisyest monsters in all the ships were(certainly on those I sailed on) were the Polar Atless(Think thats how it was spelt) generators. Happy days and nice crews.

Abbeywood.
28th December 2009, 05:49
I doubt if there's anyone old enough on SN to have sailed on White Star's "Brittanic" but I believe her, and her sister-ship ("Olympic"?) had double-acting FOUR strokes!

I'm sure I've seen a picture of one of these engines, somewhere, but I'm not 100% certain.

I seem to remember looking at the forest of push-rods and thinking what a nightmare they must have been for maintenance.

Can anyone confirm whether I'm right---------------or is it time to call for "the-men-in-white-coats"? Salaams, Phil(Hippy)

Think the sister-ship to the Britannic was the Georgic.Last of the White Star liners

steve2
1st February 2010, 11:36
The ultimate 'development????' of the double actor was, I belive, proposed by Blue Flue. This was having the top half as diesel exhausting to a waste heat unit which then provided steam for the bottoms. This could be only a smoko story- does anyone know the truth of it? If it is true then another case of Mans inhumanity to Man.
Best Regards. Steve2

chadburn
1st February 2010, 14:54
The ultimate 'development????' of the double actor was, I belive, proposed by Blue Flue. This was having the top half as diesel exhausting to a waste heat unit which then provided steam for the bottoms. This could be only a smoko story- does anyone know the truth of it? If it is true then another case of Mans inhumanity to Man.
Best Regards. Steve2

Sounds a bit like the Scott-Still Oil two-stroke Engine, although intially steam would be raised by the normal burner method in the boiler @ 150lbs per sq in, the steam then being used to start and manoevering the main engine, it is quite likely that once the diesel side had fired up then the exhaust gas would then be used to keep the boiler running as normal with the exhaust gas boiler.

Billieboy
1st February 2010, 15:48
Does the Scott-Still bit, refer to the manufacture of amber liquid?; one has to ask!

Blackal
1st February 2010, 17:04
Sounds a bit like the Scott-Still Oil two-stroke Engine, although intially steam would be raised by the normal burner method in the boiler @ 150lbs per sq in, the steam then being used to start and manoevering the main engine, it is quite likely that once the diesel side had fired up then the exhaust gas would then be used to keep the boiler running as normal with the exhaust gas boiler.

I was feverishly trying to remember the name of that engine (Thumb)

I'm sure I have an Institute of Marine Engineers' publication of that - kicking around somewhere.

Al (Thumb)

Jim S
2nd February 2010, 21:22
There was an Institute of Marine Engineers paper "The British crosshead marine diesel engine between the wars" published in 1994 by Dennis Griffiths of Liverpool John Moores University that gave a brief history of the Scott-Still engine.
The concept was devised by WJ Still and although a number of licences were granted only Scotts of Greenock and Plenty and Sons of Newbury made any progress. The Plenty-Still design was aimed at coasters and small ships but got little further than an experimental engine and a 3 cylinder engine for the drifter Larus. Blue Funnel agreed to trial a larger Scott-Still engine on the understanding that Scott would replace the power plant if not successful.
Dolius built in 1924 was fitted with two Scott-Still engines and seemed to be proving a success leading to a more powerful version being fitted in Eurybates built in 1928.
Dolius was lost during WW2 but Eurybates survived. Difficulty in maintaining full power without burning fuel in the boiler was a problem with the more powerful machinery. By the late 1940's it was taking considerable effort to keep Eurybates running and a decision was taken to replace her Scott-Still engines with 5 cylinder two stroke diesels of the Scott type.
Only a handful of these Scott diesels were built. A look at their cross- section indicates that the design had similarities such as the rotary exhaust valve to the Sulzer design.

chadburn
2nd February 2010, 21:44
Between the Wars there was a number of Marine Diesel Engines which were put to the test, some no longer exist like the Scott-Still, Camellaird-Fullagar (opposed piston two-stroke), Neptune (two-stroke), Vickers (four-stroke). There was also the known ones like the Doxford, Werkspoor and Armstrong Sulzer, B&W, the reason why there was an upsurge of interest in the marine diesel was not just the possible fuel/space saving but the high number of steam turbine blade failures in the 1920's which was giving Owner's great concern.

Blackal
4th February 2010, 11:27
I've found the publication I had read so many years ago.............

It's 'The Still Engine for Marine Propulsion' by Archibald Rennie, M.I.N.A

http://www.shipsnostalgia.com/gallery/showphoto.php?photo=219412

(Reprinted from the transactions of the Institute of Engineers and Shipbuilders in Scotland, Vol LXV)

It was published in 1922 and is a Scott's Shipbuilding and Engineering Company Ltd - publication

must have a re-read some evening.

Al :)

chadburn
4th February 2010, 13:58
I wonder if this publication was one of a number from different diesel engine builders as proposals to a Committee which was specially formed in 1922/23 to investigate the progress of the marine diesel engine as a viable power source. The Committee was formed from members of the Insitutes of Mechanical Engineering and Naval Architecs plus the Engineer-in-Chief of the Fleet with the remit to test engines, propellors and hull shapes. The Chairman of the Committee was Sir George G. Goodwin and a proposed test vessel had been offered from Richardson Westgarth.

Blackal
4th February 2010, 14:05
I think you are correct - the introduction indicates something of that ilk.

Al (Thumb)

Blackal
7th February 2010, 20:25
I found a sectional drawing of the Scott-Still engine -

http://www.shipsnostalgia.com/gallery/showphoto.php/photo/219983

Al

mala141414
24th February 2010, 03:35
Had a bit to do with them back in the sixties but never saw anyone with roots blowers. B&W did indeed use them but MAN did not as far as I know.

Peter Short
11th March 2010, 23:47
I came across this interesting thread, by coincidence I have just been reading about the early B&W double-acting four stroke engines that were fitted to Gripsholm in 1925 (Atlantic passenger liner for Swedish-American Line), and then Kungsholm in 1928. These were the largest diesel engines ever fitted to a passenger ship and were a bold step by the makers and ship owners.

The Gripsholm engines were twin six cylinder B&W, reversible, four-stroke, double-acting, each producing 6750 bhp at 125 rpm. Bore 840 mm, stroke1,500 mm. Blast air supplied by 3 x 700bhp four cylinder B&W engines driving compressors (only two required). Auxiliary equipment was driven electrically, so there were also three 500bhp, three cylinder B&W diesels driving generators. (Only two required).

What is interesting however is that these pioneering engines apparently gave excellent service for the life of the vessel. On their maiden voyage the two engines developed 16,300 bhp, and good fuel economy. In 1949 the ship was given a major reconstruction, but the original machinery was left in place, and went on to give good service until she was scrapped in 1966.

Kungsholm was given similar engines, except they were eight cylinders versions of the same design. This ship kept its original machinery until she was scrapped around 1960.

Britannic (1930) and Georgic used the same standard B&W design, built by Harland & Wolff. Apparently these were the last Harland built engines to use blast injection. Britannic used ten cylinder engines with the same 840 mm bore and 1500mm stroke. One difference was that waste heat boilers were used (the earlier ships had oil-fired boilers for heating and water evaporation).

Apparently the most work required to keep these engines running was the constant upkeep of the blast air compressor valves. Also during manoeuvring the engine rooms of Britannic and Georgic were always full of engine smoke because the blast injection system would cause the cylinder relief valves to lift during starting.

Info taken from Power of the Great liners by Denis Griffiths.

By the way, from what I can gather, there were many double acting diesel engines, both two and four stroke, used in this period (1920ís-30ís).

Geoff Craven
7th April 2010, 13:08
In my younger days I was lucky enough to sail as a junior engineer with Blue Funnel and some of those vessels had B&W single acting two strokes and at least one had a double acting version (three pistons in a liner 23ft long!) Years later I came across a film that had been made on the 'Belarophon' renamed the 'Bell' for the duration. One scene shows the start up of the single acting two stroke. The name of the film was 'the sailor who fell from grace with the sea'.

JT McRae
8th April 2010, 02:15
Geoff, it's funny you should bring up the name of that movie. The start-up of the main engine is the only thing I remember about it. It's been many years since I saw the movie but I have always thought it was a Doxford, so I stand corrected.
Tim

hamishb
10th April 2010, 16:59
In my younger days I was lucky enough to sail as a junior engineer with Blue Funnel and some of those vessels had B&W single acting two strokes and at least one had a double acting version (three pistons in a liner 23ft long!) Years later I came across a film that had been made on the 'Belarophon' renamed the 'Bell' for the duration. One scene shows the start up of the single acting two stroke. The name of the film was 'the sailor who fell from grace with the sea'.

Hi Geoff, The Belarphon had a Kincaid engine
Eng No227 7 Cyl, 750mm Bore 1500mm main piston stroke 500mm exhaust piston stroke 7000BHP @ 107RPM Trial Speed17.0Knot Service Speed 16.0 Knot. Trial date 20/09/50 Built by Caledon Shipbuilders Yard No 473.
My interest in the ship is that as an apprentice I worked with my journeyman on the replacement of half of the crankshaft.
The ship discharged her cargo in Glasgow then towed to Greenock where the engine was dismantled and stored in one of the ship's holds while the crankshaft was replaced. It took a wee while I cannot remember how long but we worked 24 hours a day at it, we were on the nightshift.
An interesting experience.
Anyone remember my nextdoor neighbour Ch. Eng Jim Breslin, steam fanatic as I remember didn't like grease driven.
Regards
Hamish

quiki000
15th April 2010, 21:17
Hello,
I read the articles about double-acting 4-stroke diesels with interest! Did you know that the Dutch factory "Werkspoor" built a series (of eight, I believe) double-acting fourstrokes of her own design? Incredibly complicated; 8 cylinders for 4000 hp!
If anybody is interested, I could find a description with photo somewhere!
Hans Guikink
Holland

chadburn
15th April 2010, 21:43
The very first diesel engined sea-going ship "Vulcanus" was engined by Werkspoor with a standard 4 stroke in 1910, they were the World leader's for many years.