In the morning of June 21, 2008, the world was stunned by the sinking of 23,820 tons, “Princess of Stars”, the largest passenger ship in the country, when she was caught at the height of the fury of typhoon “Frank”. More than 200 people died and about 600 others remained missing up to this day.

A few days ago, a tragic event in domestic shipping would again hit the headlines of major newspapers. Another passenger ferry, the 7,280 tons Superferry 9, sunk but this time in moderate weather conditions.
Ironically, after several days of news coverage, the media would stop writing about the accident. They find politics and the forthcoming national elections a more sensational story than the sea tragedy. Perhaps, they got tired of reporting about sea disasters in Philippine waters as it seems to have become a common occurrence in the country. Nevertheless, let us recall that event and analyze what might have gone wrong with the ill-fated ferry.
Superferry 9 left the southern port city of General Santos on Saturday, 5th of September, and was to arrive in Iloilo the following day, Sunday, before it got into trouble.
In the early morning hours of September 06, 2009, the ferry started listing heavily to starboard side. The crew, in their efforts to calm the panicking passengers, said it was normal (perhaps they’ve experienced similar conditions in the past). But by day break
, the vessel listed more to starboard side, where it finally capsized and sunk 9 miles off the coast of Zamboanga Del Norte.While several hundred passengers were rescued by responding coastguard, commercial and fishing vessels, 10 people perished and about 30 others are missing,
The cause of the tragedy was not clear. There were rumors that the vessel listed to one side because of a hole on the hull. Definitely, a vessel will heel as soon as sea water enters her compartment. But the laws of stability tells us that ingresses of seawater alone won’t be enough to capsize her.
Modern vessels are now constructed to have several bottom tanks, completely separated, segregated and independent with its other. So much so that, when the hull is punctured, only the compartment adjacent to the damage side will be flooded, not the other compartments or the entire vessel. I’ve seen one vessel in Japan Sea with severely damage hull as a result of collision with another freighter. She safely reached port, listing to one side, and went straight to the repair yard.
Therefore, there must be other factors that might have caused her to overturn. It cannot be the shifting of unlashed cargoes to one side (passengers heard loud crashing of weights near their cabins) nor the flooding of compartments, it can only be the LOSS OF HER STABILITY.
At the start of investigation, Capt. Jose Yap, the Master of the hapless ferry, told the probe team of the Board of Marine Inquiry (BMI) that strong winds of up to 10 knots may have caused his vessel to capsize. I find his story totally unbelievable, incredible and ridiculous. It was as if he was talking to people who have never been to sea before.
The photo below is an example of Force 3 sea condition (max winds 10 knots). You can see that the height of wave
s can be safe enough even for a small wooden boat to travel.Capt. Jose Yap continues to explain that he noticed the vessel was slightly listing to port side several hours after departing the port of General Santos.
According to the laws of stability, a ship may develop a list for only two reasons –
a.) If the center of gravity is out of the centerline of the ship (caused by improper distribution of cargoes or when ballast tanks have uneven content);
b.) If the ship has a negative GM
Between the two conditions, (b) is most dangerous as it can spell disaster for a vessel.
Obviously, the Master was unaware of the stability condition of his vessel at the time of tragedy. He was desperately trying to correct the list and upright the vessel by filling up ballast water into its heeling tanks, not knowing that if his ship is already on a negative GM, the resulting free surface effects (the movement of water from side to side inside the tank) would worsen the vessel's condition as it would further increase the negativity of its GM.
Since time immemorial, Stability in domestic shipping has always been taken for granted. In fact, most of time, it is being ignored by people manning the vessel. Yet, stability continues to be one of the major cause of shipping disasters in our country.
Actually, the lists, sea conditions, entry of seawater or shifting of weights are just some of the aggravating factors but they’re not really the cause why vessels capsize. I will try to explain, as simple as possible, for the reader to understand how a ship can turn over regardless of any kind of weather conditions.
Gravity and Buoyancy are two kinds of forces that influence a floating object. The former pulls the object closer to the mass of the earth (sinks the object), the latter acts in reverse (upward force keeping an object afloat).
In normal condition, the center of gravity (CG) and center buoyancy (CB) is in line with each other, specifically at the center of the floating object, of which the position of the former is always higher than the latter.
The point or location of “Metacenter” (M) is of special interest to a cargo officer as it is precisely what is being calculated to form the basis for determining stability. At any instances, this should be higher than the center of gravity (CG).
The Metacentric Height (GM) is the height or distance of the Metacenter (M) from the center of gravity (CG) (see below diagram). How high or low is the M from G determines how stable a vessel is.

The term “Rolling Period” means the time taken by a ship to roll from one side to the other and back again. A large GM can cause a ship to be “stiff”, meaning she will have shorter rolling period. A small GM can cause a ship to be “tender”, meaning she will have longer rolling period. A negative (-) GM means the position of the center of gravity (CG) is higher than the Metacenter (M), Under this condition, you can forget about the rolling period as this can cause a vessel to capsize when heeled to one side by either internal or external forces.
A ship state of equilibrium determines whether, when she is tilted, she will right herself, remain as it is, or turn over (capsize).
A ship is said to be in “stable equilibrium” when, if she were inclined by external force, she would try to return to the upright position.
In “unstable equilibrium”, when inclined by external forces, she would try to heel still further until she capsizes (this is what happened to “Princess Of The Orient” and perhaps to “Superferry 9”).
The state of “stable equilibrium” is achieved when a vessel attains its ideal, positive GM (not too large, not too small). The drawing below explains how this occurs.
When heeled to one side by any kind of forces, the center of buoyancy (CB) moves downward and creates a righting lever (GZ). The lever pushes the vessel upright. How fast or late the upright action depends on the height of the metacenter. With negative (-) GM, there won’t be any righting lever at all. What you’ll get is a capsizing couple (inverted GZ lever)

The primary cause of a negative (-) GM is when a ship has more weights on top than at the bottom.
A prudent Master should calculate and know his vessel’s GM at any stage of the voyage. If he determines that it is getting smaller but couldn’t control the inflow of cargoes, he should correct this inadequacy by adding non-cargo weights at the bottom (filling up of ballast tanks, specifically double bottom tanks). The idea is to move G further to the bottom, thereby increasing its distance with M.
Care should be taken when taking in ballast water. Before a tank is fully loaded (top up), the stage when it is half-filled produces the greatest effect of “free surface”. It can further aggravate her already negative stability .In short, it will become worst before it gets better. So that, it is always advisable to touch the ballast tanks in port, prior to sailing, while the vessel is stationary. Filling up empty tanks with ballast water at sea, with negative GM, in adverse weather conditions, is tantamount to committing suicide.
Obviously, Superferry 9 was in the state of “unstable equilibrium” prior to her capsizing. What led her to this condition can perhaps be traced from the time she departed the port of General Santos city.
The above explanation may appear simple. But the calculations involve in determining GM is a bit tedious and complicated. However, with the present, modern computerization system, the procedure is simplified by installation of loading computers, designed and programmed for specific vessels.
What I have related so far are mostly the technical aspects of stability. Perhaps, these may already sound boring to some readers. But the emphasis here is that the people who regulate shipping, particularly PCG and MARINA, must be well knowledgeable on this subject. Considering that this is one of the major causes of shipping disasters, they should require Masters to demonstrate his vessel’s stability by presenting a GOM (corrected GM) calculation prior to sailing. Unfortunately, not too many coastwise-trading Master can perform the calculations since, they said, this is not required by port authorities. On the other hand, even if they do learn to calculate and the document will eventually be required before departure, none of the shore personnel of PCG or MARINA will understand the figures. The Master can present a computation of his income tax returns and they won’t know the difference.
During our last “Maritime forum”, the PCG representative (MARINA, the lead agency in maritime safety, did not show up) admitted that nobody checks the stability of the vessel before sailing. They usually rely only on the “Master’s Oath”.
“By signing and presenting this document”, The PCG official said, “the Master swore that his vessel is seaworthy and in stable condition”.
Common sense dictates that a mere piece of paper can not attest to the seaworthiness and stability of a vessel. If the port authorities will always believe whatever the Master says, just because he is “the one in command” and is “suppose to make sure that his vessel is safe”, then it is just like saying: ‘THE LIVES AND SAFETY OF PASSENGERS AND CREW ALWAYS REST WITH THE MASTER”. If this is the case, where does the culpability of the state come in? What is the use of inspecting the vessel before departure? Will mere inspection of documents, life-saving equipment and counting the number of passengers ensure the safety of the vessel? Expired documents, lack of safety and emergency equipment or overloading of passengers do not cause a vessel to sink. A negative stability does.
The biggest problem we have at the moment is the overlapping of function and responsibilities of people regulating domestic shipping. There are just two many government agencies taking part in the control and operations of domestic trading vessels. We have the DOTC, MARINA (under DOTC), PCG, PPA, PRC, MTC and sometimes the Maritime Police. We have a common saying that- “too many cooks spoils the broth”
But, whoever is the one in-charge, the people boarding and inspecting vessels should not leave “any stone unturned” in ensuring the vessel’s stability and seaworthiness. The following should be verified before sailing -
1) Proper distribution of containers and heavy cargoes,
2) Proper and adequate lashing of cargoes;
3) Adequate GM (in addition to GOM calculation sheets, check the condition of cargo holds and ballast tanks)
4) Vessel’s integrity (Inspect vessel’s hull, bulkheads and superstructures)
I am sure any one, or maybe all, of the above might have caused Superferry 9 to capsize.
There is now a move in the house of representative to create a “Maritime Safety Board”, something that I recommended some 4 or 5 years ago. The young and naïve congressman of Bataan had been sitting on my 12 pages manuscript for the same period now.
But even if a board is created to oversee maritime safety, but the person in-charge will just be another government appointee, it will only be “the same dog with new leash”.
To be fair with PCG, among all government agencies involved in domestic shipping, they are the ones who can most likely enforce maritime safety. However, before they can really be effective, their people must learn the following:
1) Trim and stability
2) Calculation of Metacentric Height (GOM)
3) Calculation of shearing force and bending moments
4) Free Surface effects
5) Meteorology and laws of storm.
6) Cargo Handling and care of cargo during the voyage
7) Safety and emergency procedures
Lately, the government of Australia issued an advisory to their citizens against traveling by passenger ferries if there are other means of transport available. They said our passenger ships are unsafe. PCG chief, Admiral Wilfredo Tamayo, disputed this statement saying our passenger ferries remains to be safe despite the occasional shipping accidents. But statistics don't lie. We still hold the record for the worst maritime disaster in the world (Sinking of Dona Paz). It remains unbroken up to this day. Unless corrective measures will be taken, our passenger ships will always be unsafe,
I don’t know about the people in the government, but I feel frustrated and embarrassed to the international shipping community that sea accident has become common in a country considered by the world as the major supplier of seafarers.
I’ve said time and again that the only way to stop sea disasters in our country is for our government to set politics aside and leave the industry to the shipping experts. These are the seasoned, experienced Master Mariners and Chief Marine Engineers, not the politicians who are appointed to their positions on the basis of not what they know but whom they know.
I hope the bright people in the DOTC, MARINA and PCG and our lawmakers will pause for a moment and think about what I wrote in this article.
Meantime, the question remains- When will these shipping tragedies stop? How many more lives will be lost? When are we going to learn our lesson?
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