# Crankcase Relief Valves



## Shilo (Mar 31, 2020)

Learned folks
Any idea when Crankcase relief valves became mandatory?
I'm aware of Reina del Pacifico-11 Sep 1947, described elsewhere in here, maybe the worst incident recorded of this type.
Killed 28, injured 23.
Didn't sail in it, but I saw a B&W engine in a hull built in Japan in 1985, and I'm quite certain it did NOT have crankcase relief valves.
They're easily seen, so I'm sure I didn't just miss them.
Thaks, and take care


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## henry1 (Mar 25, 2015)

Don't know when they became mandatory but I was on a twin eight cylinder Goterverken tanker built about 1964, the relief valves exhausted upwards. I sailed on it in 1970 and it had had an explosion on one engine a couple of years before, the oiler had seen sparks when he was doing the scavenge drain pots and called the 4/E so they were both standing in the middles over the relief vave opening when it lifted, both died. After that metal screens were fitted on the side of each engine with a door you had to open to get to the scavenge drains. All the Xheads were fitted with long rods that extended out of the crankcase to a microswitch, if a Xhead bearing wore down the Xhead would touch the rod and sound the alarm.
One night as 4/E on the 12/4 watch as I approached the desk on the bottom plates between the two engines I could hear a clicking noise and saw the microswitch lever was jumping on No 6 unit Stb'd engine, I asked the 8/12 4/E what had he done and he answered nothing, it hasn't alarmed. I told him to go get the 2/E (only phone to bridge and C/E and you never phoned the C/E in those days) and I began to slow the Stb'd engine, was also concerned that the shaft generator tripped at 70 rpm, the 2/E turned up and just stopped the engine. After an hour the crankcase was opened and the Xhead white metal was sticking out the sides like soft toffee.


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## Tim Gibbs (Apr 4, 2012)

Shilo said:


> Learned folks
> Any idea when Crankcase relief valves became mandatory?
> I'm aware of Reina del Pacifico-11 Sep 1947, described elsewhere in here, maybe the worst incident recorded of this type.
> Killed 28, injured 23.
> ...


Really ?!


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## pippin (May 13, 2008)

As a mere R/O aka Sparks - what the _~#_ is a crankcase relief valve?!!


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## makko (Jul 20, 2006)

I don't know when they became mandatory. IACS unified requirements, under M9, mention first release in 1970.

The valve opening value is 0.07 Bar or 1 lb/in2! While they should be regularly tested, it is a good idea always to check them after the engine has been repainted. Epoxy paint can glue them shut! All valves that I have seen exhaust downwards, between the plates into the bilge/tank top space.

When studying, we did a little exercise for a large bore Xhead engine to see, approximately, what internal pressure would blow the door off - If memory serves, it was a little over 3 lb/in2.

Investigation has shown (as per Reina Del Mar) that if there is an explosion and the crankcase door is breached, the secondary explosion will be of a much greater magnitude.

Rgds.
Dave


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## Peter Hewson (Mar 12, 2019)

Albeit, from the "dim and distant" past . I am sure that I was on a 4 Leg Doxford Built 1953, which had Crank Case Explosion Relief doors?.
Pete


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## captainconfusion (Aug 13, 2020)

I am unsure of general, merchant ships and the registration, these days: However the machinery is in a registered vessel usually built to a classification requirement, and survey/inspection procedure.
However under Older Uk regulations while a passenger ship was built to classification rules, it was also subject to rules and an inspection procedure as required by Government inspectors surveyors.
One question slow speed catherdral engines may have crankcase explosions doors: I wish to beg the question of the modern high/medium speed marine diesels, either geared/electrical/hydraulically connected to the main shaft, do they have explosion doors in the crankcase?? Or is the speed and power of each crankspace, within an explosion regulation limit, according to energy that could be created under explosive conditions.


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## makko (Jul 20, 2006)

Captainconfusion,
Yes, there are relief valves. There are other systems, apart from the Graviner oil mist detector, which monitor the conditions in the crankcase. These are based on oil temperature, electromagnetic discharges (dissimilar metals), etc. However, as asked by Insurers whether a cylinder/crankshaft failure was predictable on a Wartsila med. speed engine, my answer, based on calculations, was,"less than two seconds"!
Rgds.
Dave


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## captainconfusion (Aug 13, 2020)

noted ! Thank you.


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## Tim Gibbs (Apr 4, 2012)

captainconfusion said:


> noted ! Thank you.


We had a disaster in Ellermans in the late ' 50s on the City of Bath.. A bottom end bearing bolt failed and the ensuing malee in the crankcase caused a crankcase explosion that blew the crankcase doors off - despite the crankcase relief valves. An engineer died of his injuries.


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## Duncan112 (Dec 28, 2006)

I remember being told by a lecturer that some of the H&W built engines didn't have relief valves, relying on a crankcase exhaust fan, don't know how effective they were though!!


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## mrcruisine (Oct 10, 2010)

Shilo said:


> Learned folks
> Any idea when Crankcase relief valves became mandatory?
> I'm aware of Reina del Pacifico-11 Sep 1947, described elsewhere in here, maybe the worst incident recorded of this type.
> Killed 28, injured 23.
> ...


When is a good question, as more than a few engineers were killed. I was on reefers in the 1980's and we had medium speed Pielstick engines, and they were considered high risk. Engine crankcases were fitted with Graviner oil mist detectors, which I had to set up and calibrate when we got full away on passage and changed over onto heavy oil. That was always fraught as well and more than once I peed everyone off by accidently tripping the engine as they were very fiddly and located in a precarious location. The crankcase covers had relief valves but that was I told small protection in a major incident and I was advised never stand too close to them.


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## JKB (Jul 6, 2007)

pippin said:


> As a mere R/O aka Sparks - what the _~#_ is a crankcase relief valve?!!


Here's my understanding, subject to correction if I've got it round my neck...
It's a large spring-loaded non-return valve mounted on the side of the crankcase. Sometimes called an "explosion door." It has three main functions:
1. To let the pressure out if a hot spot, such as a piston seizure or a bearing failure, in the crankcase ignites oil vapour and causes an explosion. This prevents the pressure blowing the actual doors off.
2. To seal again once the pressure has dropped so that air can't get sucked back in to feed an even greater explosion.
3. The valve incorporates a flame trap to prevent flames getting out into the engine room.


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## pippin (May 13, 2008)

Thank you kind Sir - I am now much the wiser.
My first ship in '65 was the CITY OF PORT ELIZABETH GPLC.
It had twin Doxfords. It used to frighten the life out of me on my rare forays down into the engine room from the boat deck.
There was a walkway between the engine tops. 
Those pistons going up and down, the flailing rubber hoses, noise and heat.
Had I known about the dangers of crankcase relief valves I would not have ventured further down in my quest for distilled water for the Radio Room emergency batteries!

I remain in awe and admiration for those who worked in the E/R.


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## Willyone (Aug 13, 2007)

I joined PSNC in 1969 and heard all about the Reina. Years later as 2nd on the Hornby Grange I saw what such an explosion could do. She had suffered an explosion, been repaired, but even years later there was evidence all over the engine room. Happily no engineers were injured in this instance.


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## Tim Gibbs (Apr 4, 2012)

pippin said:


> Thank you kind Sir - I am now much the wiser.
> My first ship in '65 was the CITY OF PORT ELIZABETH GPLC.
> It had twin Doxfords. It used to frighten the life out of me on my rare forays down into the engine room from the boat deck.
> There was a walkway between the engine tops.
> ...


The "flailing" rubber hoses weren't a problem ........ until they broke, spraying hot water around  On one ship a hose broke and wasn't spotted for a few minutes by which time the water pouring off the top platform was doing a good job of washing down the open front switchboard below


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## Peter Hewson (Mar 12, 2019)

Tim Gibbs said:


> The "flailing" rubber hoses weren't a problem ........ until they broke, spraying hot water around  On one ship a hose broke and wasn't spotted for a few minutes by which time the water pouring off the top platform was doing a good job of washing down the open front switchboard below


A not infrequent happening, Fortunately the (ship) in question had the Switch board out of range!, but getting to the stop valve!, could get you scalded!. We had a coil of the hose rubber kept in a 40 gall drum down the shaft tunnel, the length required was marked on the E-R plates. Even in the dark and (relatively) cool the hose seemed to deteriorate quickly. Not to forget, entering the stinking hot, crankcase at sea to replace/repack the "elbow's". Whilst being coated with hot oil.!


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## Tim Gibbs (Apr 4, 2012)

Peter Hewson said:


> A not infrequent happening, Fortunately the (ship) in question had the Switch board out of range!, but getting to the stop valve!, could get you scalded!. We had a coil of the hose rubber kept in a 40 gall drum down the shaft tunnel, the length required was marked on the E-R plates. Even in the dark and (relatively) cool the hose seemed to deteriorate quickly. Not to forget, entering the stinking hot, crankcase at sea to replace/repack the "elbow's". Whilst being coated with hot oil.!


Ah! Those porous swinging links and elbow glands........ memories best forgotten


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## DaveU (Oct 2, 2014)

JKB said:


> Here's my understanding, subject to correction if I've got it round my neck...
> It's a large spring-loaded non-return valve mounted on the side of the crankcase. Sometimes called an "explosion door." It has three main functions:
> 1. To let the pressure out if a hot spot, such as a piston seizure or a bearing failure, in the crankcase ignites oil vapour and causes an explosion. This prevents the pressure blowing the actual doors off.
> 2. To seal again once the pressure has dropped so that air can't get sucked back in to feed an even greater explosion.
> 3. The valve incorporates a flame trap to prevent flames getting out into the engine room.


 Very true with your comments, but two things to add from my experience with the MAN 52/55 proto types when we had many explosions from piston seizures whilst trying to modify piston skirts and rings to remove direct LO cooling from pistons
1. In one case the round explosion door opened as designed, but the large sealing O-ring was displaced out of its groove and prevented the door from re-sealing, no secondary (the big explosion) hence why I'm able to type today.
2. Given the medium speeds in container ships, in our case 3 engines are in close proximity, when the doors did explode open, LO at over 85 Deg C was a blasted on to the floor plates, jetted off the plates into the next engine, bouncing off her and up into the head room of the plates above. I was saved twice by pure luck of just being outside the blast area. On watches I used to move pretty quickly between engines.
The good old days.


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## Chillytoes (Dec 9, 2006)

Getting back to the subject of crankcase explosion doors - I recall the head teacher at Sydney Tech, Len Bateman, relating that after the Reina Del Pacifico disaster, 'John Lamb was set loose in a shed somewhere attempting to reproduce crankcase explosions with the view to finding answers'. I assume that this work was undertaken for the British Internal Combustion Engine Research Association (think I've got that right?) because most relief valves had BICERA cast on them.
I don't recall reading anything about this work in Lamb's autobiography, but in his 1958 Obituary mention is made of work he did on this subject for which Institution of Mechanical Engineers awarded him the Akroyd-Stuart prize (year?). Guess that his work was put into effect soon after, but when they became mandatory - don't know.


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## Victor J. Croasdale (Nov 28, 2016)

I started my engineer cadetship at Kincaid in 1974. We built engines under licence to B&W or under B&W sub licence from H&W, depending to the engine type. Every engine had explosion doors. I sailed on some ships built in the late 60s with explosion doors.


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## GrahamHoll (Jan 4, 2021)

pippin said:


> As a mere R/O aka Sparks - what the _~#_ is a crankcase relief valve?!!


It’s basically a safety valve that relives explosive pressure buildup in a engine crankcase . Hot spots in an engine due to a variety of reasons ( bearing failures) cause lubricating oils to become an explosive mixture. The resulting rapid pressure buildup ( actually a deflagration, not an explosion) blows off the crankcase doors. The relief valves relieve the pressure before it reaches a dangerous pressure. 


pippin said:


> As a mere R/O aka Sparks - what the _~#_ is a crankcase relief valve?!!


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## captain confusion (Aug 15, 2020)

GrahamHoll said:


> It’s basically a safety valve that relives explosive pressure buildup in a engine crankcase . Hot spots in an engine due to a variety of reasons ( bearing failures) cause lubricating oils to become an explosive mixture. The resulting rapid pressure buildup ( actually a deflagration, not an explosion) blows off the crankcase doors. The relief valves relieve the pressure before it reaches a dangerous pressure.


dear Graham, age comes before beauty, i am going to be personal here?? I am please as a past seagoing engineer, under the red duster, not the stars and stripes? At my delicate age of 78. I ask politely how old are you? Are you an old sea dog? Did you before becoming a sparkiie [ i assume a radio officer and not an electrical officer] spend time learning your skills as a radio officer at some marine collage, or lodgings, or in the armed forces with other young seagoing men who where all learning the different trades, expertise required to man and run a merchant or naval vessel/ship???
While you live and work during your watch time among the great and the good nearest the bridge and captains cabin, and his lot of mottly officers drink tea and have cakies with the passengers or wives and supernummeries that may be on board? Have you not off watch talked to the engineers and requested invited oneself for a conducted tour of the ships many machinery spaces,?? Or indeed in or on port watch have you not again asked the engineers if one could be given a walk around the engine spaces??
It is all in that experience of being a seadog? Whether on a small fishing/ coastal boat or a deep sea liner! Or passenger ship-ferry/ container general cargo, or even on a naval vessel??
You as sparkie radio officer in my day may have been the last link between the ship/ shore- help and abandoning ship, and you may have been asked what is the problem and the emergency?? You maybe the last link, can you live with that?? Do you know your ships? Or are you a passenger supernummery required by regulation to sit in an ivory tower and just - key tap" your way through the voyage? I hope note?? Please join the crew and ask , like you have done, not a screen website but your felow shipmates, you are more than we would say under the "" red duster" board of trade aquaintainces?? We all as crew signed the same ships articles!!!


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## pippin (May 13, 2008)

Wow! Captain Confusion.

I was indeed a Radio Officer or "SPARKS" (not sparkie) under the Red Duster.
Any R/O who just sat in the Radio Room would soon go off his trolley - believe me, many did just that!
I took a great interest in what happened elsewhere on board.
Naturally mostly on the bridge because that was geographically closer but also that my work interacted a lot with navigation. Wx, Nav Wngs, DF, time sigs, radar, echo sounder & etc.
I also spent time with the Engineers. Forays down into the Engine Room for distilled water to top up my emergency batteries. Welding rods to fabricate an emergency VHF Ae. Long lengths of cable to run an AC TV on a DC ship
from my Radio Room AC supply so we could all watch football finals in the smoke room.
I was somewhat fascinated by the massive machinery and would ask questions about it.
Good relations with the Bosun or Serang were essential when I needed help with my aerial system.
Let alone cadging some canvas with which to make a hammock for sunbathing.
I can't even take a guess at the number of crew radios that came into the shack for me to fix.
"No man is an island" - especially aboard ship, if that's not too much of a confusing metaphor!

"What goes around, comes around" is one of my mottos!


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## Varley (Oct 1, 2006)

I think that by posting on a particular thread one is "joining the body of the Kirk" so to speak and not simply broadcasting to an anonymous aether. One is certainly not inviting any response from SN on anything to do with seafaring comment (of course we do do that when trying to improve their presentation of it).

So, Captain Confusion, jumps in on Pippin's working frequency (something of the chancer there perhaps) while most of us expect to connect on a frequency open to all on watch.


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## rogd (Jul 2, 2018)

Seems like Captain Confusion needs some sort of relief valve.


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## captain confusion (Aug 15, 2020)

rogd said:


> Seems like Captain Confusion needs some sort of relief valve.


oh ah! I have i said too much, apologies all around. Regards and best wishes to all?


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## pippin (May 13, 2008)

Thanks for coming back to us Capt Confuse - no offence was taken.

I have bared all, now it is your turn to tell us about your time at sea!


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## captain confusion (Aug 15, 2020)

pippin said:


> Thanks for coming back to us Capt Confuse - no offence was taken.
> 
> I have bared all, now it is your turn to tell us about your time at sea!


dear pipin, my time at sea was an experence in life which has stood me well, in my professional, and personal life.
I am/ was an engiineer cadet with bp tankers, spent my time at college in middlesbrough, shipyard time on the tyne, then alternate phase 3 at south shield marine tech, then off to sea as a cadet, motor and steamships,. Concentrated on steamships for my ticket 2 and then 1st class sitting the tickets and college at hull tech. I then married first trip back, i was able to take my wife! Next trip held the rank of 2/e with c/e ticket, again could take my wife. The trip was a pier head jump to 2/e full of experience, some good some bad, we as a crew spent during the voyage 11 days adrift on a steam turbine Ship. We dry fired the boilers due to feed water condensate problems. No power at all!! only able to work with hand tools diesel genny nackered air start diesel would not fire up , lighting by and huricane lamps. Cooking was provided to the ship using the er forge, and carefull use of the galley oil stoves. We used everything from dead ship, filling the boilers by hand using buckets, after the affected furnace tubes were plugged, then fired up by natural draft, hand boiler oil fuel pump [ using diesel], (2small burners tips]. Raise pressure all services isolate steam on deck etc. When up to full steam pressure opened up the steam line to one turbo feed pump, then to one ta, open up main condenser, put ta on the board, bring in circ pumps. Then float the two boilers, and as we had feed evap problems we brought on one steam steam generator with a steam heating, but a seawater feed, and blow down as a feed water steam generator carefull not to prime, feeding the freshwater storage tanks, checking salinity, then with isolated steam lines to the only working evaporator coils, and then generating boiler feed water, for the high pressure boilers water was not the 7-11 salinity, but acceptable 20. We only had a total before the shut down of 40 tonnes and to fill each boiler required some total of 7 tonnes per boiler [14 tonnes in total]? At the time we were on passage from perth to the gulf, we broken down off bombay/ karachi, and when we had secured the plant in the engine room, and services we crawled to bahrain at 4 to 5 knotts for voyage repairs. We made it? We then loaded and went to aden where i paid off knackered. I then served in the bp fleet on motorships doing my C/E steam time, i was successful.,
After this i held the post of assistant fleet safety officer. I then took the personal decisiion to move shoreside and become home base firstly in the trawler industry in hull, then shipping company in glasgow, and then service engineer with stal laval london. At this time i was a gypsie in the marine industry.
Then auntie offer the opportunity of extras and a place of work in newcastle and then london, as an engineer surveyor, finished my career up enjoying the work an meeting all the people- last 10 years seconded to hse offshore division based in london and norwich,
Not a perfect career, but one to experience,


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## CenpacRounder (Jun 5, 2020)

Chillytoes said:


> Getting back to the subject of crankcase explosion doors - I recall the head teacher at Sydney Tech, Len Bateman, relating that after the Reina Del Pacifico disaster, 'John Lamb was set loose in a shed somewhere attempting to reproduce crankcase explosions with the view to finding answers'. I assume that this work was undertaken for the British Internal Combustion Engine Research Association (think I've got that right?) because most relief valves had BICERA cast on them.
> I don't recall reading anything about this work in Lamb's autobiography, but in his 1958 Obituary mention is made of work he did on this subject for which Institution of Mechanical Engineers awarded him the Akroyd-Stuart prize (year?). Guess that his work was put into effect soon after, but when they became mandatory - don't know.


Hi, What year were you at Sydney Tech?
I did my "Chief's" there in 1971.
We might have been classmates.


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