# Any explanation for this?



## Shipbuilder (Jun 30, 2005)

A U-tube video of a rescue from a sinking fishing boat. The boat is evidently filling fast, and sinking rapidly. When she is almost gone, at about 2 minutes into the video, the main engine appears to start up and the propeller starts whizzing round! It is still going strongly as the boat vanishes beneath the surface. In the first two minutes, the propeller is stationary. How can a diesel suddenly start up when the engine-room must be filling with water?
Bob
http://youtu.be/RTE3yEF9JwU


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## ART6 (Sep 14, 2010)

Air under pressure from the hull sinking entering the engine air intakes and forcing the engine to rotate?


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## Dartskipper (Jan 16, 2015)

It's not a very big trawler, so maybe the engine is fitted with an electric starter motor. The engine was stopped with the control lever still in "Slow Ahead". The water flooding the engine room shorted out the terminals and caused the Starter Motor to fire up the engine again. Unless we can identify the boat in question and find out what machinery she had. If it was a marinised truck engine e.g. Gardner, Volvo, or similar, this is one possibility. Another could be something fell forwards as she is sinking bow first. A large spanner or fire extinguisher falling against a "Start" button on a control panel maybe?


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## Gulpers (Sep 8, 2005)

She was the Irish fishing vessel *luda Naofa*, see *here*.
Perhaps someone will be able to identify her machinery details or those of her sister *Star of Hope*.


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## randcmackenzie (Aug 31, 2005)

Just the sea running through the nozzle and forcing the propeller to rotate I think.

The propeller is stopped at the beginning of the video, which indicates the engine was out of gear.


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## Farmer John (Feb 22, 2012)

It is running at about 29 seconds into the video, and at 2 minutes in, it is difficult to tell if it is running so fast the camera can't catch it, and then it slows down till you can see it.


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## Shipbuilder (Jun 30, 2005)

I have just looked again, and am fairly sure it was stopped until 2 minutes. When it starts, it rapidly speeds up well beyond what I would have though a bit of water slopping past it could do, and it still seems to be spinning when completely out of the water. I had thought maybe the electric starter shorted out and started to turn the engine over, but could not see it turning it as fast as that. I am not an engineer, but I really wondered if a diesel would work at all when full of water. The fact remains though, that the propeller is spinning, not just turning, and I can't think of any explanation!
Bob


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## ART6 (Sep 14, 2010)

Shipbuilder said:


> I have just looked again, and am fairly sure it was stopped until 2 minutes. When it starts, it rapidly speeds up well beyond what I would have though a bit of water slopping past it could do, and it still seems to be spinning when completely out of the water. I had thought maybe the electric starter shorted out and started to turn the engine over, but could not see it turning it as fast as that. I am not an engineer, but I really wondered if a diesel would work at all when full of water. The fact remains though, that the propeller is spinning, not just turning, and I can't think of any explanation!
> Bob


Doing an Internet search, the boat had a 492.43 kW main engine, so it wouldn't have been a marinised truck engine -- much too big. And as you suggest, it certainly wouldn't turn over if filled with water: no IC engine could ever do that! The YouTube video https://www.youtube.com/watch?v=sLplZ2tBzZQ shows the screw only starting to spin as the boat goes bow down and the stern rising up out of the water, suggesting that the engine room was filled with air and not flooded at that point so the engine wouldn't be either. It might well have been able to turn over.

The next conjecture I am not sure of, but an engine that size feels to me a bit big for a starter motor like a truck would have, but I only ever sailed on one motor ship so I am no expert. That, as all of them, used starting air from compressors to turn the engines over, and the compressors were driven by auxiliary diesels. The Iuda Naofa had a quite sizable auxiliary engine which, perhaps, drove a starting air compressor to fill the starting air cylinder? So now, when the bridge dipped beneath the water, could something have set off the starting air system and set the main engine turning? Sea water shorting an electrical contact on the bridge panel maybe? 

There doesn't seem to be any indication in the video that the engine actually fired, and upside down I don't suppose it would, but it could still turn over quite fast under starting air for a short while.


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## Ron Dean (Aug 11, 2010)

ART6 said:


> Doing an Internet search, the boat had a 492.43 kW main engine, so it wouldn't have been a marinised truck engine -- much too big. And as you suggest, it certainly wouldn't turn over if filled with water: no IC engine could ever do that! The YouTube video https://www.youtube.com/watch?v=sLplZ2tBzZQ shows the screw only starting to spin as the boat goes bow down and the stern rising up out of the water, suggesting that the engine room was filled with air and not flooded at that point so the engine wouldn't be either. It might well have been able to turn over.
> 
> The next conjecture I am not sure of, but an engine that size feels to me a bit big for a starter motor like a truck would have, but I only ever sailed on one motor ship so I am no expert. That, as all of them, used starting air from compressors to turn the engines over, and the compressors were driven by auxiliary diesels. The Iuda Naofa had a quite sizable auxiliary engine which, perhaps, drove a starting air compressor to fill the starting air cylinder? So now, when the bridge dipped beneath the water, could something have set off the starting air system and set the main engine turning? Sea water shorting an electrical contact on the bridge panel maybe?
> 
> There doesn't seem to be any indication in the video that the engine actually fired, and upside down I don't suppose it would, but it could still turn over quite fast under starting air for a short while.


I can see both conjectures in the above being feasable explanations.
Is it possible that both conditions apply i.e. Assuming the engine room was not filled with water, the air receiver for starting, supplies the cylinders to turn over the engine, at which point compression ignition takes over?

Ron.


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## ART6 (Sep 14, 2010)

Ron Dean said:


> I can see both conjectures in the above being feasable explanations.
> Is it possible that both conditions apply i.e. Assuming the engine room was not filled with water, the air receiver for starting, supplies the cylinders to turn over the engine, at which point compression ignition takes over?
> 
> Ron.


I suppose it's possible that a marine engine could start briefly when standing up on end, since they are designed to accept being chucked about a bit. However, although the photos of the boat don't show it, I would guess that the exhaust is on top of the superstructure somewhere, in which case when the screw started to turn the exhaust would have been well under water, and there is no sign of the normal starting smoke in that area that I can see. Whether or not the engine could start with its exhaust immersed in water to quite a depth I have no idea. Possibly some of the motor guys in this forum might know?


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## Shipbuilder (Jun 30, 2005)

I think I would go for the compressed air, as water would not affect it.
It has been mentioned that the engine may have been out of gear. Does that mean that the propeller shaft would not turn even if the engine was running?
Bob


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## ART6 (Sep 14, 2010)

Shipbuilder said:


> I think I would go for the compressed air, as water would not affect it.
> It has been mentioned that the engine may have been out of gear. Does that mean that the propeller shaft would not turn even if the engine was running?
> Bob


This is where I am out of my depth here (!!), but I assume that an engine of that size would not be capable of reverse running, and so would rely upon some sort of gearbox for reversing. So then, the boat is taking on water from a hull breach, and the main engine is either stopped or has stopped itself. Anyone have the presence of mind to disengage the gearbox, or even why should they bother? Getting the f**k out sounds like a better bet if there is rescue nearby.


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## Dartskipper (Jan 16, 2015)

Ref post #8 by Art6.

492.43Kw equates to 660HP.

The ***mins QSM11 Marine Diesel is turbo charged and produces 660HP. It can use either 12v or 24v Electric Starter motors.

www.tadiesels.com Click on "***mins"" in list of brands, scroll down to QSM11.

There are no doubt other makes of marinised industrial or truck engines built to a similar specification. (I'm using "truck" in its American fashion, i.e. "lorry")

So we can't rule out electrical shorts entirely.


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## Dartskipper (Jan 16, 2015)

The reports of the sinking say a pump was delivered to help pump out the water flooding in. I'm wondering if the crew left the main engine running as well to operate their own bilge pumping system? As she sinks by the head, did something loose knock the control into "Ahead"? This would explain the prop spinning, but it seems to start slowly and then accelerate. Hmmmmm, thinking cap on again...


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## japottinger (Jun 16, 2004)

I agree with randcmackenzie above


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## Mad Landsman (Dec 1, 2005)

There is a lot of water passing though the nozzle just as the prop starts to rotate. 

A cropped screen shot for you to ponder:


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## Dartskipper (Jan 16, 2015)

The prop is above the water as the stern raises. As the boat sinks, water splashes through the nozzle, but the prop remains still. The boat starts sinking, but as the prop is still clear of the water, it starts rotating quite fast. The trawler then sinks rapidly, and the all ready spinning prop then enters the water. Or am I looking at something different?


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## Mad Landsman (Dec 1, 2005)

Maybe an air pressure wave just above the surface induced by the rising and falling relative water level, this is channeled towards the propellor by the keel and becomes amplified by the nozzle. 
The simple air flow starts the prop moving and as water enters it increases the rotation speed. 
As the prop starts to rotate quite fast it goes out of the camera shot.
One sees an acceleration just before it disappears and the brain extrapolates that it must then be going even faster than it probably is, if one could see it.

There is also the wind and helo downdraft to factor in.


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## Dartskipper (Jan 16, 2015)

Mad Landsman said:


> Maybe an air pressure wave just above the surface induced by the rising and falling relative water level, this is channeled towards the propellor by the keel and becomes amplified by the nozzle.
> The simple air flow starts the prop moving and as water enters it increases the rotation speed.
> As the prop starts to rotate quite fast it goes out of the camera shot.
> One sees an acceleration just before it disappears and the brain extrapolates that it must then be going even faster than it probably is, if one could see it.
> ...


That is beginning to make sense now. Thanks M.L. (Thumb)


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## Derek Roger (Feb 19, 2005)

randcmackenzie said:


> Just the sea running through the nozzle and forcing the propeller to rotate I think.
> 
> The propeller is stopped at the beginning of the video, which indicates the engine was out of gear.


The sea running through the nozzle was quite a wave and fast moving . You are correct all the other proposals with an obviously flooded engine room are to be discounted . Derek


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## sparkyjon (Jul 30, 2013)

Shipbuilder said:


> A U-tube video of a rescue from a sinking fishing boat. The boat is evidently filling fast, and sinking rapidly. When she is almost gone, at about 2 minutes into the video, the main engine appears to start up and the propeller starts whizzing round! It is still going strongly as the boat vanishes beneath the surface. In the first two minutes, the propeller is stationary. How can a diesel suddenly start up when the engine-room must be filling with water?
> Bob
> http://youtu.be/RTE3yEF9JwU


The prop seems to start when the boat is almost vertical. Maybe the fuel supply was interrupted but then returned ? Quite a dramatic rescue!


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## Don A.Macleod (Jul 11, 2004)

I put it down to the wind in this part of the world (my home is only 40+ miles from this location) and if the shaft was free from engine/gearbox then I reckon the devious types of wind up here would have no problem rotating the prop.After all thats why the renewable energy brigade have such an interest in the area.Just a thought mind you!


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## little.O (Jun 17, 2011)

****mins marine units*

If the unit was of "pressure time" type of speed control it may rev up out of control.The speed control usually operates by the injection pressure being controlled internally in the engines fuel system.If,however, the pressure is raised externally the speed will also be raised in proportion to the pressure applied.This is why some ***mins engines in an overtutrned truck will not switch of "on the key". It is also why they are installed in marine units with a float chamber alongside them and level with them.If you couple one up to a higher service tank they rev their nuts off and you have to shut off the fuel supply and wait for them to run out ( or blow up!) because they won't shut down.


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## chadburn (Jun 2, 2008)

It is not unknown for a diesel to run on it's own lubricating oil given the right/wrong conditions when the diesel fuel has been turned off.


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## OilJiver (Jun 30, 2014)

chadburn said:


> It is not unknown for a diesel to run on it's own lubricating oil given the right/wrong conditions when the diesel fuel has been turned off.


Absolutely right Chadburn. Thankfully have only experienced it once. And very, very scary it is too. The engine runs away and the only way of stopping it (unless a small engine with de-comp arrangement) is to starve it of air. Wrapping a lagging pad around the air filter/TC inlet does the job. Not at all nice though – not when the thing is about to spit the rods out.

However, that will not be the case here. The sump oil won’t be where it’s supposed to be and that’s for sure. But the engine certainly won’t be dieseling on any of it that gets past the rings under these cir***stances.

The guys who’ve already pointed out that the engine is de-clutched and the prop is being spun freely by water washing through the kort nozzle are on the money.


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## ben27 (Dec 27, 2012)

good day shipbuilder.sm.30th jan.2015.02:16.#4 re:any explanation for this,i have know explanation.but to say the lifesavers did a great job,it is a brilliant video of the rescue.thank you for posting regards ben27


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