Tanker collision off China


#85

Will the Sanchi / CF Crystal collision be followed by changes to rules and regulation by IMO?
There was an article in Fairplay yesterday, but unfortunately I cannot find it on an open source so I copy and past it here:

Hopefully more come from the loss of 32 lives on the Sanchi then is likely to come from the 33 lives lost on El Faro.


#86

Why is it that postmortems on a collision is so difficult? The root cause of this collision is the failure of one ship to “give way” to another. Now, why does that happen? Either ignorance or ego; and both are unacceptable. I’m of the opinion too many of indigenous deck officers of that part of the world get their maritime license from a cracker-jack box!! Really!! It’s sad.

When things are good, yes, it’s good. But WOW. When that one butt-head guy shows up, and won’t change course, it’s bad. And the idea of playing chicken with 100k displacement tons is unbelievable.

Ok, after that rant, now the serious part.
After several airplane crashes, it became universally required that aircraft must have TCAS (traffic collision avoidance system or traffic alert and collision avoidance system) installed. Using transponder information, the system communicates with each other and diverts one aircraft up, and the other aircraft down if there is risk of collision.

Why not utilize the AIS to provide a similar collision avoidance system? It IS THE TRANSPONDER!!
And, it must be legislated that mariners SHALL follow the instructions of the nautical TCAS. It must be a “SHALL” because two commercial jets augured into the ground due to human override of TCAS in Europe. Had the pilots followed TCAS instructions, both aircraft would have arrived safely at the destination.


#87

According to http://www.tankeroperator.com/ViewNews.aspx?NewsID=9327 the M/T Sanchi wreck is now resting at only 115 m depth and it should be easy to recover bodies and to examine it, incl. the engine room.


#88

likely to be the FW tank in that position, one port, one starboard


#89

Thought that also but normaly they are not that high and mostly more to the central line of the ship and also these tanks go over more frames. you can see that


#90

The urgency may be on recovering the HFO remaining on board.
Whatever remains of the cargo may be of less importance, since it is light condensate that will evaporate relatively quickly when in contact with air.

At 115 m. WD that should be relatively easy, at least compared to emptying the Prestige at .3500 m.:
https://wwz.cedre.fr/en/content/download/1733/.../5-repsol-YPF-resultsprestige-en.pdf

Here in video form:


#91

The M/T Prestige oil spill 14 November 2002 is typical. It was not a collision but caused by the Greek Master Mangouras of the tanker not having close-up inspected all the ballast and cargo tanks of his ship prior loading understanding that the tanker would split in two in a storm. What an idiot. Of course it never happened. But according Spanish authorities it did!
During the voyage there was a little crack in the hull, oil leaked and Master Mangouras asked Spanish authorities to allow him to enter a safe port to fix it. It was refused because Spain didn’t like small oil spills in their ports of refuge. Imagine that!
That’s why I since then always recommend my clients never to mention cargo oil leaks as cause of suddenly entering a port of refuge or just stopping.


#92

#93

this piece has a tiny bit more on collision damage (area), and states that a robot “located the point of impact near number 2 and number 3 cargo holds - a triangle shaped hole stretching 35 metres”.


#94

As the collision was not perpendicular I assume the structural damages were all above waterline where the double hull tanker outer/inner sides were ripped open by the flare of the forecastle of the bulk carrier. The bulbous bow of the bulk carrier probably never touched the tanker outer side below waterline. The double hull ballast space was down flooded by burning cargo oil from the breached cargo tanks making things very nasty. Depending on the subdivision of the tanker burning oil could have spread in the double hull heating up undamaged cargo tanks from below, etc. Double hull tankers are actually very unsafe in high energy collisions. IMO has approved better designs but they are not permitted by USA/USCG.


#95

The ballast water tanks in the double hull typically have the same longitudinal and transverse subdivision as the cargo tanks.

The ballast water tanks were probably flooded by cargo oil, but the fire was probably only at the oil/air interface just like in the cargo tanks.


#96

No. The double hull ballast tanks/void spaces are either U-shaped (full beam) or L-shaped (half beam with a center line division). And the cargo tanks subdivision is not clear to me - one or two longitudinal bulkheads.
The burning cargo oil flooding the double hull spaces probably didn’t fill the double bottom area completely; maybe there was fire in the double bottom in the beginning.
The fire probably deformed the structure producing more cracks and fractures, so oil could leak into other non-cargo spaces. The hydrocarbon gas there then exploded.
It has been suggested that DH tanker ballast tanks should always be full of inert gas to avoid the above, but it makes regular inspection difficult.
Let’s face it! DH is a sub-optimal solution of oil tanker design promoted by the USA.


#97

It’s too bad no one has come up with a better design.


#98

I’ll check the tank arrangement on Sanchi once I get my access to IHS Sea-web back, probably in a few hours.

edit: 7 tank pairs (6x2 cargo, 1x2 slop)


#100

Oh yes there are a better design and it has been around since 2010:


#101

Thanks. The 6x2 cargo tanks are each say 15 000 m3. With bad luck you slice open two of them in a collision, the oil up floods two empty double hull L ballast tanks over say 60 m length and catches fire. The fire in the ballast tanks will then heat up bulkheads of the forward and aft intact cargo tanks and, I am certain, will deform the bulkheads and produce more internal leaks. So very quickly four cargo tanks are on fire … and that’s the end.
But I am still curious about the engine room. Did the watch keeping engineers survive?


#102

Jeez Louise…I guess next time I want to kid someone I should add (JUST KIDDING!) at the end of my post.


#103

Thanks for linking to DNV. So I take the chance again to link to (my 20 years old website) about my efforts >20 years ago to improve oil tanker safety at sea and protection of the marine environment. Every time the moderators consider it SPAM but it is just a history lesson.
It didn’t work. I wonder why I cannot link to 20 years old info.


#104

I’m still a bit skeptical about the possibility of having a fire within the double hull. Even if there were air pockets, there wouldn’t be enough oxygen to sustain a “hot” fire - there would just be a lot of black smoke. In addition, there’s awfully lot of cool sea water to remove that excess heat. Still, something happened as the fire spread so efficiently. Poor inerting?


#106

Who knows? Witnesses say that the burning Sanchi wreck suffered from explosions before going down after the collision/fire. I once inspected an ore/oiler in drydock at Amsterdam and while discussing, e.g. if ship was gas free, there was an explosion aboard (+ mushroom cloud). A welding spark had dropped into an access trunk to the double bottom and ignited a pocket of gas down there. I left and never inspected the ship. Another of our tankers were doing hot work on deck and a welding spark dropped through a BW hatch in the deck and … there was an explosion. The tanker was supposedly gas free.