On March 31, in fine weather, with everything onboard as routine as could be, the Stellar Daisy began to list, listed badly, rolled over and sank in a few minutes, taking with her all but two of her crew of 24, and a lot of sintered iron ore fines loaded at Ilha Guiba in Brazil for carriage to China. The published accounts of the two survivors make it clear that the loss was sudden, that there was insufficient time to abandon ship in good order, and that they owed their survival in the water to luck.
The weather was good and everything onboard this big ship was perfectly routine – until it wasn’t.
She didn’t hit anything, nothing caught fire, there was no explosion. She just took on water – a lot of water, very suddenly, she listed, she capsized and she sank.
The Steamship Mutual P&I Club, with which the ship was entered, were contacted by this site and issued, true to their reputation, a firm “No comment”.
The owners were equally helpful. The class society, Korean Register, has gone as far as to confess that the rules might need to be looked at, IACS has done a little genteel hand wringing, the flag state, the Marshall Islands, has done nothing, the IMO has joined IACS in genteel hand wringing, and the other ore carrying ships converted from tankers, in the large fleet of Polaris Shipping and in the fleets of other owners, have gone sailing blithely on, give or take the odd crack in deck and side shell, but, as we all know, “That sort of thing happens all the time…”
We don’t know what happened. We do know that it should not have happened, and we do know that it should not happen again. Since the Marshall Islands have failed to convene a formal enquiry, we are not going to get an authoritative answer to the question, “Why did it happen?”
We have been told, by its apologists, that the Marshall Islands is not up to investigating this sort of loss, and indeed we have heard that “the only people with the skills and resources to investigate this properly are the UK’s Maritime Accident Investigation Branch” – whom the Marshall Islands have failed to appoint to do their job for them.
Since the owners won’t comment, and neither will their P&I club nor their flag state nor their class society, we must speculate.
What follows is, I hope, reasonably well informed speculation. If I am mistaken, the owners, or their P&I club or their flag state or their class society, are very welcome indeed to correct me. I am deliberately ‘trailing my coat’ in the hope of drawing out those who may know more than I do, because, as an industry, we need to know, before it happens again.
We know that the Stellar Daisy began life as the VLCC Sunris III, at the Nagasaki yard of Mitsubishi Heavy Industries (MHI) and was delivered to her first owners in July 1993. She was a single hull tanker, built by one of the world’s leading shipyards, and she was converted in China to a very large ore carrier in 2009.
I am now going to speculate and say five things, each of which may be wrong.
First, as I recall, MHI were, at that time, exponents of the use of higher tensile steel to reduce the lightweight of ships.
Second, as I recall, MHI’s usual practice – as was the practice of other good yards building single hull crude carriers – was to paint the deckhead and the bottom of each tank and to carry the paint up and down a distance of around three metres on the side shell and bulkheads.
Third, as I am quite sure, because I asked an eminent class society, and it’s obvious anyway, when you convert an oil tanker into a dry cargo carrier, you can disable the inert gas system, and common sense tells us that that is what you will do.
Fourth, as is obvious to everyone, the stresses imposed on a hull by a full cargo of liquid with a specific gravity of around 0.8 are going to be very different indeed to the stresses on a hull imposed by a full cargo of granular ore and fines with a specific gravity of around 5.
Fifth, if the conversion was carried out to a good standard, which we have no reason to doubt, there will have been considerable strengthening of the structure in way of the new tank tops of the new cargo holds, to redistribute the stresses that we have just remarked on, and there will have been similar strengthening of the decks in way of the new hatch covers for those same holds.
Now I am going to quote several very eminent naval architects whom I have had the pleasure of knowing over the decades – in large ships’ structures, the devil is in the detail.
In a good shipyard or a good design bureau and in good class societies, a great deal of thought goes into detail design to avoid stress raisers and to avoid crack propagation.
We now have a ship which, for 16 years, spent roughly half her time with crude oil (whether sweet or sour is more than we can know) in her tanks and almost all her time with those tanks filled with an atmosphere of inert gas – scrubbed funnel flue gas. This is a recipe for low rates of corrosion. The original inert gas systems were developed, not to stop tankers from blowing up, but to slow down the rate of corrosion in uncoated cargo tanks. As Michael Caine once said, “Not a lot of people know that”. Now, you do.
In owning and operating single hull tankers, we used to spend some time thinking about which tanks were permanent ballast tanks and which were cargo tanks and from time to time we would consider changing tanks over, to even out corrosion. And we used to spend quite a lot of time thinking about stress cracking where Isherwood System longerons passed through ring frames, and stress cracking in decks. Many 1970s VLCCs were scrapped for just these reasons, at rather modest ages.
The same ship now spends about eight years during which what were once cargo oil tanks, and are now ballast tanks, are full of sea water for about half the time, and full of damp air for the rest of the time. This is a recipe for much higher rates of corrosion inside those tanks. An ore carrier or ore oiler has side ballast tanks which are much larger than those of a bulk carrier or ore bulk oil carrier, so flooding a single side ballast tank on an ore carrier is going to have a bigger effect on the ship’s stability than flooding a space on a conventional bulker will have.
I suspect that the true cause of the loss of the Stellar Daisy may lie in people thinking, as so often happens in our industry today, about their own ‘part of ship’ and not thinking enough about the ship and her cargo as a whole.
The ship is now 23 years old, nobody expects her to pass her fifth special survey, and she is carrying ore, which may or may not be loaded very quickly.
Dear reader, do you think that this was – do you think that this is – a good idea?
Because, as I have said before, ships should not suddenly sink, in good weather, in 2017.
Unsafe at any draft – Part one can be read by clicking here.