Port Engine Going Full Speed Astern

Georges G.

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The SOLAS rules you quote are minimum acceptable performance times. Can you imagine a course recorder chart printout from a ship that responds as lowly as the minimum requirements?
Like it or not, all the merchant vessels of the planet ocean go by the Solas very minimum requirements and sometimes under those very minimum. Rarely higher $$$
 

Jim Currie

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Jim, a vessel the size of the Costa Concordia is maneuver most of the time by instruments and especially at night.

Yes, Georges, I know that. The words most of the time are relevant in this case.

The most trust in instrument of all is without any doubt the ECDIS.

Yes Georges, I know that too.

With such a navigation instrument, if the vessel is certified ECDIS (no paper chart on board) and it is operated in a DGPS or WAAS region
you could at the limit close all the curtains of the navigation bridge windows and you would see the reef as big has you wish on the PPI.


Only if the reef has above surface profile. If it was under water, you need side-scan sonar. Don't think CC had that.

You would also see all the COG / HDG Vectors, CPA, TCPA, Bearings & Distances that you like. If you know how to operate an ECDIS, you can set all the alarms possible. Therefore, you must be totally out of your mind to drive such a vessel into an island at 16 knots in perfect visibility!!


Yes Georges, I know that too. However, the Captain of the CC did not drive his ship deliberately into a reef or an island. He did what many modern Masters and bridge officers do, relied too much on electronics and showed off by reverting to steam navigation.
As a Marine Accident Investigator working for Lloyds and US Underwriters for over 25 years recent (10 years ago) experience, I have seen that happen all too often. I have even investigated an incident where the bridge Watch fell asleep and the ship ran into an anchored Semi-submersible. The ship was aptly names the "Alert".
You may also be interested to know that I was involved from the very beginning in experimentation with 'hands free' navgation whereby we linked computer managed propulsion to auto pilot, IGPS, radar, depth recorders, side scan sonar and electronic charts. One of our tasks was to exit a Fjiord hands free and sail blind for 300 miles and attempt to hit a target the size of a rowing boat in mid ocean over a distance of 300 miles. We hit it spot on. The equipment you describe today, evolved from such experiments.
 
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It must have hit while the ship was turning away. The stern must have swung into the rocky outcropping while the bow was swinging away.
 

Georges G.

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Just a thought. How did the rock miss the stabaliser?
Because at the time of the allision, the vessel was not «sliding» on a Port Wheel along the reef but was turning «Hard to Stb’d», the rate of turn was probably well over 30 degrees per minute to Stb'd, a vessel is turning by the stern as the peripatetic pivot point is located at approx ¼ length from the forward perpendicular, the gash is well aft of the stabilizer on the port quarter and so on…

Here is a cheap S57 Vector Chart that shows «clearly» the reef. To avoid it, you don’t need to see it! Equipped like she was, you could make that Salute in dense fog with no problem whatsoever. If the captain wanted to beat the record of the closest Giglio Salute, he succeeded! But he got 16 years jail medal…

costac10.jpg
 
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Titanic's stern was never in danger, by that time the New York was alongside at her after part she was already going astern and the New York was under control of the tugs.
For the benefit of those not familiar with the incident, there were two steamers moored at berth 38 down by the lower Test quays near the juncture of the Test and Itchen rivers when Titanic left from Ocean Dock berth 44. The larger of the two moored steamers, the SS Oceanic, was moored against the quay while the smaller of the two, the SS New York, was moored abreast and outboard of the Oceanic. The adverse reaction leading to the incident with the SS New York was magnified because of the shallowness of the restricted waters that separated Titanic from the two moored vessels. As Titanic’s bow approached the sterns of the two vessels, a small repulsive force was set up between Titanic and the two smaller moored vessels pushing them both up against the quay. Soon the hydrodynamic force turned from one of repulsion to one of attraction as a low pressure area was set up between the advancing Titanic and the two smaller steamers. With the attractive force came an induced turning moment that acted to swing the stern of the two moored vessels outward toward the passing Titanic. As Titanic approached abreast of them, the forces became too great for the mooring lines of New York to bear, and her mooring lines suddenly snapped.

"As the bows of our ship came about level with those of the New York, there came a series of reports like those of a revolver, and on the quay side of the New York snaky coils of thick rope flung themselves high in the air and fell backwards among the crowd, which retreated in alarm to escape the flying ropes. We hoped that no one was struck by the ropes, but a sailor next to me was certain he saw a woman carried away to receive attention. And then, to our amazement the New York crept towards us, slowly and stealthily, as if drawn by some invisible force which she was powerless to withstand…On the New York there was shouting of orders, sailors running to and fro, paying out ropes and putting mats over the side where it seemed likely we should collide; the tug which had a few moments before cast off from the bows of the Titanic came up around our stern and passed to the quay side of the New York’s stern, made fast to her and started to haul her back with all the force her engines were capable of; but it did not seem that the tug made much impression on the New York. ... At first all appearance showed that the sterns of the two vessels would collide; but from the stern bridge of the Titanic an officer directing operations stopped us dead, the suction ceased, and the New York with her tug trailing behind moved obliquely down the dock, her stern gliding along the side of the Titanic some few yards away. It gave an extraordinary impression of the absolute helplessness of a big liner in the absence of any motive power to guide her.” -- L. Beesley

The tugs Neptune and Vulcan caught New York and pulled her back toward the quay while Titanic, stopped dead in her tracts by reversing her engines for a short time, was slowly drifting backward. But controlling the New York was no easy task.

"Someone sang out to me to get up and push the New York back, but such a thing was impossible. Had I got between the two ships we would almost certainly have been jammed. Instead, I turned the Vulcan around and got a wire rope on the port quarter of the New York. Unfortunately, that rope parted, but our men immediately got a second wire on board, and we got hold of the New York when she was within four feet of Titanic. Our movements were all the more trying because the broken mooring ropes from New York were lying in the water, and we stood a good chance of fouling our own propeller. Every rope on the New York snapped, the stern lines being the first to go..." – Captain Gale, tugboat Vulcan.

From photographs it could be seen that Titanic had started to drift backward after her engines were finally stopped, having been first reversed. My guess is that the anchor was dropped to keep her from drifting further backward. The entire incident caused about an hour's delay in leaving Southampton.

Ioannis, I would not say that Titanic was never in danger with New York coming as close as 4 feet before she was taken under control by the tugs.
Incident at Southampton.gif
 
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Jim Currie

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According to the voice recordings, at the moment of impact, the helm was hard a port, not hard a starboard. This suggests an attempt to swing away from possible contact.
Unfortunately, I do not have a plan view of the vessels but the angle between the tip of the stabaliser and the first point of contact on then hull suggests that at the time of impact, the ship was pointing way to the north. north eastward., not 350 True as declared in the narrative. That being the case, then she turned when almost due south of the rocks, not where her master said she did. See here:
costa concordia ong.10.jpg
 

Georges G.

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Both vessels altered their bow «away» from the danger but their stern, which had much more leverage momentum, was thrown «toward» the hazard. Similar hull damage and both ship were lost. The logic of trying to escape an inevitable hazard was far more dangerous than to attempt to minimize the damage.

concor10.png

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Decision making in a threatening context; the psychological stress and anxiety may induce a rigid cognitive response on the part of individuals. People tend to draw upon deeply ingrained mental models of the environment that served them well in the past. Individuals also constrict their information gathering efforts, and they revert to the comfort of well learned practices and routines. This cognitive rigidity impairs a leader’s ability to surface and agree to a wide range of dissenting views.
 
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Ioannis, I would not say that Titanic was never in danger with New York coming as close as 4 feet before she was taken under control by the tugs.
I said her stern was not in danger. I think it was Capain Gale who said the New York would have hit Titanic at the high of the 4th funnel with her stern.
 

Georges G.

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According to the voice recordings, at the moment of impact, the helm was hard a port, not hard a starboard. This suggests an attempt to swing away from possible contact.
Jim, if you put the wheel Hard Over to Stb’d on a twin rudder and wait just a little until the Rate of Turn Indicator shows like 30 degrees per minute, even if you redirect the wheel Hard to Port in 28 seconds, you will have to wait until your face turn yellow-green before she starts to swing to Port. Costa Concordia had a 50,000 metric tons displacement (quite the same as the Titanic). At 16 knots, the momentum reach like 1,500,000 tons-m/s. Ounce that momentum is directed and accelerates in the wrong direction, unless you’re in open water, your king is checkmated!
 

Jim Currie

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Titanic was heading down river. As far as I can remember, the tide would have turned and together with the outflow of the river Test, there would have been a small seaward-setting current. Apart from tidal and river currents, when a big ship like that stops suddenly, the wake current continues to push her ahead until the reversing engines overcome the forward motion. Don't think an anchor would have been of any use during the New York incident.
 

Jim Currie

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Jim, if you put the wheel Hard Over to Stb’d on a twin rudder and wait just a little until the Rate of Turn Indicator shows like 30 degrees per minute, even if you redirect the wheel Hard to Port in 28 seconds, you will have to wait until your face turn yellow-green before she starts to swing to Port. Costa Concordia had a 50,000 metric tons displacement (quite the same as the Titanic). At 16 knots, the momentum reach like 1,500,000 tons-m/s. Ounce that momentum is directed and accelerates in the wrong direction, unless you’re in open water, your king is checkmated!
Have no experience of twin rudder ship handling, Georges. However, I would hate to steer a ship such as you describe in a following sea if it took so long to respond to a heading correction.
I like your wee sketches showing the coloured arrows. Try incorporating "bank cushion effect" and "displaced pivot point" due to contact with an immovable object.
 

Georges G.

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A typical case of Ship’s Interaction (Ventury / Bernoulli Effect) due to flow water restriction between a vessel proceeding too fast and at too short clearance from a shoulder moored vessel. Titanic’s Dead Slow Ahead Two was 6 knots! At slow speed, the center rudder without propeller trust on it, evolved in a turbulent and cavitation area. She must have been quite a hardheaded donkey to maneuver, if not the worst! Tugs were inevitable.
 

Georges G.

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I like your wee sketches showing the colored arrows. Try incorporating "bank cushion effect" and "displaced pivot point" due to contact with an immovable object.
Bank Cushion: no effect. We are dealing here with a steep reef surrounded by deep water that had all the room to flow freely.

The peripatetic point theory applies only to free floating vessel (neither moored, nor at anchor or aground). As soon as you touch something, a lever is created between the point of external force or impact and the center of gravity. The vessel will then turn around its center of gravity. Once the Concordia, on a port wheel but still on a Stb’d swing, stroke the reef violently, a turning lever was created between the 80 tons rock engulfed in the hull and the center of gravity. The resultant force (green) between the forward motion (black) and the heavy impact thrust (red) made the vessel turning to «Port» abruptly and in such an extent, that the wheel had to be redirect to Stb’d, away from Giglio harbour and toward deep water. A lots of fun !

impact10.jpg
 

Georges G.

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Don't think an anchor would have been of any use during the New York incident.
I don't think so. The speed was already too fast for an anchor to have any sort of efficiency. Two anchors down… might have helped a little. Anchor work: the line is fine between a hero and a zero! You had to control the speed «before» going too fast. How… by dragging via the after center fairlead, one or two tugs going full astern or by clutching one reciprocating engine at the time. Slow Speed Control is the essence of the game...
 

Georges G.

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Have no experience of twin rudder ship handling, Georges. However, I would hate to steer a ship such as you describe in a following sea if it took so long to respond to a heading correction.
Here is an official video that shows how good a twin rudder vessel steers in a following sea, obviously with the crucial aid of the stabilizers.

 

Jim Currie

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Bank Cushion: no effect. We are dealing here with a steep reef surrounded by deep water that had all the room to flow freely.

The peripatetic point theory applies only to free floating vessel (neither moored, nor at anchor or aground). As soon as you touch something, a lever is created between the point of external force or impact and the center of gravity. The vessel will then turn around its center of gravity. Once the Concordia, on a port wheel but still on a Stb’d swing, stroke the reef violently, a turning lever was created between the 80 tons rock engulfed in the hull and the center of gravity. The resultant force (green) between the forward motion (black) and the heavy impact thrust (red) made the vessel turning to «Port» abruptly and in such an extent, that the wheel had to be redirect to Stb’d, away from Giglio harbour and toward deep water. A lots of fun !

impact10.jpg
It depends very much on the bank profile. Do we know that that was? There might easily have been a bow cushion and a mid ship suction due to inequality of pressure between port and starboard sides. All academic stuff.
 

Jim Currie

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I don't think so. The speed was already too fast for an anchor to have any sort of efficiency. Two anchors down… might have helped a little. Anchor work: the line is fine between a hero and a zero! You had to control the speed «before» going too fast. How… by dragging via the after center fairlead, one or two tugs going full astern or by clutching one reciprocating engine at the time. Slow Speed Control is the essence of the game...
The ship had been canted out of the dock and was moving ahead down river in a narrow channel, the width of which was further reduced by berthed vessels. She would have had a following current and probably wind assistance. To drop two anchors while moving ahead would have been catastrophic. To drop one would have been equally so.
We must also remember that when the New York broke free at the stern, he was at the mercy of the same river and tidal currents that were affecting Titanic.
 

Georges G.

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It depends very much on the bank profile. Do we know that that was? There might easily have been a bow cushion and a mid ship suction due to inequality of pressure between port and starboard sides. All academic stuff.
FreshCruiser%2B-%2BGiglio%2BNautical%2BChart%2B1.jpg


If you observe any chart on the net, you will notice that Le Scole is a reef point surrounded by deep water. Usually, a rocky point have a steep underwater pattern and a sand point have on the contrary a gentle slope pattern. Shore interaction effect would’ve then been negligible.