Did the ship bleed off any speed with the stop order? Were there quick ways to stop or reduce the steam/ship speed? All the dampers weren't closed

[Mattie Canada]

Fireman Barrett testified they were in the process of closing the dampers (which reduces the steam) when they "crashed" into the iceberg. Hichens testified he estimated Murdoch sent the engine room telegram stop order 30 seconds after hearing the lookouts ring bell 3 times, giving the engine room an estimated 7 seconds to identify and execute the order. Are there valves that cut off the steam or is there anything else that could be done to slow it down and did the ship slow down at all even by like .1kt?

 

[Richard C Elliott]

@I'd Hit That closing the dampers is not actually important in slowing the ship. To stop the engines the main procedure is to close the steam valves to the engines. With the engines no longer using steam but the boilers still operating at full capacity the steam pressure in the boilers would rise and the excess steam would start to blow off through the safety valves, as indeed it did. To bring this under control the air supply to the boiler furnaces is reduced by closing the dampers. It is a secondary process and has no direct effect on the speed.

I believe the ship would have slowed down a little but most of that would have been due to the fact that it was turning. Putting the rudder over increases the hydrodynamic drag so ships always slow when they are turning, even if the engine revolutions remain the same. Whether the engine orders made any significant difference in the short time available is doubtful.

There was nothing else that could have been done to slow the ship.

 

[Mattie Canada]

@I'd Hit That closing the dampers is not actually important in slowing the ship. To stop the engines the main procedure is to close the steam valves to the engines. With the engines no longer using steam but the boilers still operating at full capacity the steam pressure in the boilers would rise and the excess steam would start to blow off through the safety valves, as indeed it did. To bring this under control the air supply to the boiler furnaces is reduced by closing the dampers. It is a secondary process and has no direct effect on the speed.

I believe the ship would have slowed down a little but most of that would have been due to the fact that it was turning. Putting the rudder over increases the hydrodynamic drag so ships always slow when they are turning, even if the engine revolutions remain the same. Whether the engine orders made any significant difference in the short time available is doubtful.

There was nothing else that could have been done to slow the ship.

Thanks. Do you believe the speed was the same if no stop engine order/telegram was given? I’m overall wondering if any speed was bled off from the engines

 

[Richard C Elliott]

I’m overall wondering if any speed was bled off from the engines

Do you mean engine speed (revolutions) or ship's speed through the water? The huge momentum of the ship means it would take a long time to slow down even with the engines stopped, so even if they had slowed down the engine revolutions it would be unlikely to have any noticeable effect on the ship's speed in the time and distance available.

Titanic's sea trials included a crash stop test where the engines were reversed from full ahead to full astern and the ship was stopped in a distance of 850 yards and a time of 3 minutes 15 seconds. Unfortunately we don't know whether the timing started from the order or when the engineers responded so it is difficult to apply this to the accident scenario, but you can see that a very 'quick and dirty' calculation would suggest a speed reduction of about 4 knots in 37 seconds even if a 'full astern' order had been given immediately, the engineers had been on standby and had reacted instantly. That being the case I would suggest that a 'stop' order in the circumstances of the accident probably made no significant difference to the speed at the moment of impact.

In any case it is unlikely that a small reduction in speed would have made any difference to the damage sustained so it is probably irrelevant.

 

[Mattie Canada]

Do you mean engine speed (revolutions) or ship's speed through the water? The huge momentum of the ship means it would take a long time to slow down even with the engines stopped, so even if they had slowed down the engine revolutions it would be unlikely to have any noticeable effect on the ship's speed in the time and distance available.

Titanic's sea trials included a crash stop test where the engines were reversed from full ahead to full astern and the ship was stopped in a distance of 850 yards and a time of 3 minutes 15 seconds. Unfortunately we don't know whether the timing started from the order or when the engineers responded so it is difficult to apply this to the accident scenario, but you can see that a very 'quick and dirty' calculation would suggest a speed reduction of about 4 knots in 37 seconds even if a 'full astern' order had been given immediately, the engineers had been on standby and had reacted instantly. That being the case I would suggest that a 'stop' order in the circumstances of the accident probably made no significant difference to the speed at the moment of impact.

In any case it is unlikely that a small reduction in speed would have made any difference to the damage sustained so it is probably irrelevant.

Yes. With the hard-over order given, if they issued the engine stop order or they didn't issue the engine stop order, would the speed during the collision be the EXACT same? Lightoller suggested had Murdoch ordered only the port engine to be reversed, they may have avoided it. But was there enough time for the prop to bleed off any speed?

Had they had one extra second to react, the side swipe might have been SLIGHTLY less damaging and could have kept it afloat for another 15 minutes which could have allowed the crewmen to properly assemble collapsse A & B saving roughly another 50 people. The known damage was found to be around 300' of non-consecutive "tears", perhaps if they turned a second sooner it would have only received 275' of damage, 2 seconds sooner only 250' of damage, etc. Had the ship stayed afloat for another 4 hours, most everyone could have been saved

 

[Richard C Elliott]

Had they had one extra second to react, the side swipe might have been SLIGHTLY less damaging

Possibly. It is totally speculative. @Samuel Halpern has made some interesting calculations regarding the energy involved in the collision, which you can view at www.titanicology.com/Titanica/EnergyOfCollision.pdf. The interesting thing is that it only required 1.5% of the ship's total kinetic energy to cause the damage sustained, so even if the speed was very much lower there would still have been ample energy to cause fatal damage. On the other hand it can be shown that the ship would not have been fatally damaged by a head-on collision absorbing the entire kinetic energy. (See my Could Titanic have survived a head-on impact?). There just isn't any simple relationship between the energy of collision and the resulting damage. It depends very critically on the position and angle of the impact. The Titanic's sideswipe that night was just a very improbable and unlucky event.

perhaps if they turned a second sooner it would have only received 275' of damage, 2 seconds sooner only 250' of damage, etc.

If you look at the bulkhead spacing you will find that anything exceeding 190' would breach more than the critical 4 compartments. Reducing the length a little wouldn't make any difference to the outcome.

 

[Mattie Canada]

Possibly. It is totally speculative. @Samuel Halpern has made some interesting calculations regarding the energy involved in the collision, which you can view at www.titanicology.com/Titanica/EnergyOfCollision.pdf. The interesting thing is that it only required 1.5% of the ship's total kinetic energy to cause the damage sustained, so even if the speed was very much lower there would still have been ample energy to cause fatal damage. On the other hand it can be shown that the ship would not have been fatally damaged by a head-on collision absorbing the entire kinetic energy. (See my Could Titanic have survived a head-on impact?. There just isn't any simple relationship between the energy of collision and the resulting damage. It depends very critically on the position and angle of the impact. The Titanic's sideswipe that night was just a very improbable and unlucky event.


If you look at the bulkhead spacing you will find that anything exceeding 190' would breach more than the critical 4 compartments. Reducing the length a little wouldn't make any difference to the outcome.

Thanks for the PDF; interestingly, they don't seem to reduce the speed due to the engines being ordered to stop, I'd love to know how they came to that conclusion as that's what I'm trying to figure out

With the damage, as you state, the ship could only stay afloat with up to 4 compartments, yet less damage/surface area open to the sea would reduce the flow of water entering and therefore increase the time it took to sink. If it took an extra 4 hours to sink, nearly everyone could have been saved. Napkin math would lead us to believe a 200' tear would let in 1/3 less water than a 300' tear. However, we also live in the 3D world, and some of the hull plates are reported to be separated by up to 1', if the ship turned a little bit sooner perhaps the hull plate separation would only be 6" further reducing the overall surface area open to the sea

 

[Richard C Elliott]

they don't seem to reduce the speed due to the engines being ordered to stop, I'd love to know how they came to that conclusion as that's what I'm trying to figure out

I'm not clear what exactly you are trying to figure out. A ship isn't like a car. Stopping the engines wouldn't instantly reduce the speed. It really isn't hard to figure out that the engine orders, even if carried out instantly, wouldn't have much effect on the speed in the time available before the impact.

a 200' tear would let in 1/3 less water than a 300' tear

Not entirely true because a lot depends on the geometry of the tear, but lets not quibble about that. It would still be vastly in excess of the capacity of the pumps so the eventual outcome is unchanged, and it wouldn't extend the sinking time enough to change the prospects of rescue.
I also notice that you have been even more optimistic than before and reduced the postulated length of damage even further, despite my argument that a reduced speed does not necessarily mean reduced damage.

some of the hull plates are reported to be separated by up to 1', if the ship turned a little bit sooner perhaps the hull plate separation would only be 6"

Where have you got that figure? Are you perhaps referring to hull damage on the wreck? There is nothing in the accounts of the collision to suggest that there were any openings of that width. The calculated total area of the openings divided by the length of damage gives an average width of between 0.5" and 0.75" depending on which figures you choose. The small size of that figure was what led Edward Wilding to believe that the damage must have been intermittent and modern evidence supports that opinion, but openings of up to a foot in the collision damage would be very difficult to believe.

 

[Mattie Canada]

I'm not clear what exactly you are trying to figure out. A ship isn't like a car. Stopping the engines wouldn't instantly reduce the speed. It really isn't hard to figure out that the engine orders, even if carried out instantly, wouldn't have much effect on the speed in the time available before the impact.

Not entirely true because a lot depends on the geometry of the tear, but lets not quibble about that. It would still be vastly in excess of the capacity of the pumps so the eventual outcome is unchanged, and it wouldn't extend the sinking time enough to change the prospects of rescue.
I also notice that you have been even more optimistic than before and reduced the postulated length of damage even further, despite my argument that a reduced speed does not necessarily mean reduced damage.

Where have you got that figure? Are you perhaps referring to hull damage on the wreck? There is nothing in the accounts of the collision to suggest that there were any openings of that width. The calculated total area of the openings divided by the length of damage gives an average with of between 0.5" and 0.75" depending on which figures you choose. The small size of that figure was what led Edward Wilding to believe that the damage must have been intermittent and modern evidence supports that opinion, but openings of up to a foot in the collision damage would be very difficult to believe.

You seem to be missing my keywords such as "napkin math" and did the prop bleed off .1kt or more of speed (not instantly drop like a car)

I'll ask my question a different way, if no stop order was given, would the Titanic's iceberg approach speed be the same as if a stop order was given within .1kt? She was going 22.5kts, then turned and according to the PDF calculations, she hit the 'berg at 20.7kt

To even come to this conclusion, we must know what was done by the crew to attempt to stop and so far, I can only find "closing the dampers" which is only one minor part of the stopping process

 

[Richard C Elliott]

OK, taking your points in turn:

You seem to be missing my keywords such as "napkin math"

I didn't miss that, which is why I said I wasn't going to quibble about your rough calculation but pointed out some other, non-mathematical, reasons why that reduction in the water volume wouldn't really make a crucial difference.

did the prop bleed off .1kt or more of speed (not instantly drop like a car)

Yes I noticed that you had chosen a tiny decrease in speed in that particular example and I wondered why. I admitted several times that there might have been a very small effect of the engine orders but I would regard it as not significant. A decrease of 0.1kt would seem to fit into that category. It would be far too small to have any of the effects which you later went on to discuss which is why I assumed you had changed your assumptions and were now considering a much greater decrease in speed.

if no stop order was given, would the Titanic's iceberg approach speed be the same as if a stop order was given within .1kt?

No, it possibly would not match to within that very tiny margin of difference but does that matter? My point is that any small difference there might have been would would be far too small to make any significant difference to the outcome.

we must know what was done by the crew to attempt to stop and so far, I can only find "closing the dampers" which is only one minor part of the stopping process

And so we get back to your original point. Closing the dampers was mentioned by Barratt as part of a purely factual answer to what he was doing at the time. It wasn't an answer to the question "What was done to reduce the speed of the ship?". I think even Lord Mersey, though not renowned for his technical expertise, would have been well aware that to stop a steam engine you first close the steam regulator valve. Every schoolboy railway enthusiast of the era would have known that. Are you trying to suggest that because this was not mentioned, or asked about during the enquiry, it might be that the Titanics's experienced engineers omitted this action when they received the 'stop' order?

I'm sorry if I sound a bit exasperated but you do seem to be grasping at some very short straws.

 

[Mattie Canada]

OK, taking your points in turn:


I didn't miss that, which is why I said I wasn't going to quibble about your rough calculation.

Yes I noticed that you had chosen a tiny decrease in speed in that particular example and I wondered why. I admitted several times that there might have been a very small effect of the engine orders but I would regard it as not significant. A decrease of 0.1kt would seem to fit into that category. It would be far too small to have any of the effects which you later went on to discuss which is why I assumed you had changed your assumptions and were now considering a much greater decrease in speed.

No, it possibly would not match to within that very tiny margin of difference but does that matter? My point is that any small difference there might have been would would be far too small to make any significant difference to the outcome.

And so we get back to your original point. Closing the dampers was mentioned by Barratt as part of a purely factual answer to what he was doing at the time. It wasn't an answer to the question "What was done to reduce the speed of the ship?". I think even Lord Mersey, though not renknowned for his technical expertise, would have been well aware that to stop a steam engine you first close the steam regulator valve. Every schoolboy railway enthusiast of the era would have known that. Are you trying to suggest that because this was not mentioned, or asked about during the enquiry, it might be that the Titanics's experienced engineers omitted this action when they received the 'stop' order?

I'm sorry if I sound a bit exasperated but you do seem to be grasping at some very short straws.

I'm still looking for the answer to my original question, was there a difference in speed? By no means am I suggesting anything in the stopping process, I simply want to know what was done before the collision besides the dampers and if whatever was done had an impact on the speed of at least .1kt

As I stated before, an extra 15 minutes would have made a major difference for everyone involved with Collapsibles A and B, where many died due to being exposed to the water but of course the Titanic would have still sunk

I have a few reasons I'm interested in knowing this hypothetical but mainly want to know, for the Titanic to stay afloat until 6 am, how many seconds sooner did the hard-over order need to be given?

 

[Richard C Elliott]

And I believe I have clearly stated what would have been done in response to the engine order, admitted that it might have made a small reduction in the speed and offered a reasoned opinion on why that would have made a negligible difference to the outcome. I don’t believe anyone can offer you more than that.

On your last question I consider that the iceberg was first spotted at a distance that was already too short for any avoiding action to have a very high probability of success. No matter how many seconds sooner the hard over order was given the outcome would have been uncertain. Nobody can tell you whether any difference in the orders given could have enabled the ship to stay afloat until 6 am.

 

[Mattie Canada]

And I believe I have clearly stated what would have been done in response to the engine order, admitted that it might have made a small reduction in the speed and offered a reasoned opinion on why that would have made a negligible difference to the outcome. I don’t believe anyone can offer you more than that.

On your last question I consider that the iceberg was first spotted at a distance that was already too short for any avoiding action to have a very high probability of success. No matter how many seconds sooner the hard over order was given the outcome would have been uncertain. Nobody can tell you whether any difference in the orders given could have enabled the ship to stay afloat until 6 am.

Would you mind expanding on the stopping process? "Close the steam valves", How many valves are there, and how many workers are typically tasked to close them? How long does it typically take to close the valves? After the valves are closed, how long does it take for the ship to start slowing down? Is there anything else to the stopping process other than closing the steam valves?

 

[Samuel Halpern]

From what was reported by eyewitnesses the engines did not come to a stop until one to two minutes following the collision. The engine orders came as a total surprise to those engineers on duty in the engine room at the time. They obviously did not have much time to close the stop valves before the ship struck. They only were shutting the dampers when the ship struck. As leading fireman Barrett said: "The crash came before we had them all shut." So the engines were still turning at 75 rpm as the crash came.

 

[Richard C Elliott]

@I'd Hit That just to fill in a couple of other details you asked for. There were two valves, one for each reciprocating engine. Each was operated by a single engineer turning a handwheel through many turns from fully open to closed. Engineers would be on standby next to the valves at times such as leaving port when engine orders were expected but not during long periods of continuous running at sea, which is why Sam points out that the order was a complete surprise. The engineers would not have been in place at the valve controls, adding a further delay before they even started closing the valves.