March 24, 2011

Unstable equilibrium

“Two percent of the ship’s beam,’ the logistics manager told me once again with what he thought was authoritative finality. “That is enough GM and stability for any ship, including this one”.

“Two percent!” he exclaimed, clearly getting carried away. “On this ship, that is less than forty centimeters. That should be your minimum GM.”

Our feeder container ship had just berthed, and the man himself had come aboard before we started discharging, huffing and puffing and threatening to blow my house down because I had shut out cargo at the last port since we were fully loaded. A freshly shaved 27 year old almost fresh out of business school, he had been incandescent with rage on the phone then; he could not believe that the widespread- and regular- under declaration of container weights in the trade could actually reach a stage when I would refuse to load any more since we were down to our marks- and our stability was borderline, to boot. The fact that I had- at the same loadport- disregarded his two percent hogwash out of hand had not improved his temper; I had also refused to take out any more ballast to accommodate cargo; our GM was low enough, we were a small, low powered ship and we would be going through the South China Sea in typhoon season. I couldn’t have cared less about the two percent mumbo-jumbo.

The manager was so angry now, standing in my cabin six days later, that I could almost see aftershave evaporating off his heated skin, and I could certainly smell it. So I sat him down, popped him a coke (something stronger being against the D and A policy and all that) and, without speaking, handed him a sheaf of computer stability printouts and my own calculations from the load port.

I then called the Mate on the walkie-talkie and asked him to commence discharging the containers, and make sure that- as the logistics department had planned- two shipboard cranes would start discharging simultaneously, picking up the heavy containers from the top tier.

Meanwhile, our man the manager appeared visibly flummoxed because he couldn’t understand why such elaborate calculations that I had now given him were necessary when a simple ‘two percent of the ship’s beam’ calculation could be done in two point eight seconds. He spent a few minutes pretending to understand the cheeky printouts, shuffling the papers impatiently. “Two percent,” he said again, much like the village moneylender quoting daily interest rates to a destitute farmer in a remote Indian hamlet.

The ship started listing. It went on going till it was about 10 degrees to starboard. It then seemed to stop, but then continued for another couple of degrees, stopping at about 13. Obviously cargo work had commenced and two heavy containers were being simultaneously discharged.

The effect of a list, as we all know, is more dramatic the higher you are on a ship, and the Master’s cabin is invariably high, just below the bridge deck. It may have appeared to him as if we were capsizing, because the logistics manager darted to the bridge-front porthole in my cabin. “What is happening?” he asked, obviously alarmed. “Why is she going like that?”

I sat him down again and explained, very briefly, the principles of stability to him. I also told him that the unfavourable shift in the centre of gravity with two shipboard cranes- effectively thirty metres up from the keel and picking up 35 tonnes each on a small vessel with a low displacement- was considerable. (That he seemed to believe; he ignored the wxd/W calculation I was trying to explain and instead went very pale as the ship rocked a bit, looking as if he believed that the ship’s centre of gravity had been raised to approximately 2 percent below the level of his scrotum.)

I also reminded him, while he was conveniently frozen, that the ship’s cranes were designed to work up to a fifteen degree list, at which point they would cut out, leaving us with two hanging loaded containers and the usual lopsided view of the world. I told him bad weather had an even worse effect. I reminded him that bad weather was called bad for a good reason.

The ship rocked and righted itself as the containers were discharged. The logistics manager regained some colour, finished his coke and left quickly. We never had any cargo related problems thereafter.

Another small Ro-Ro ship quite a while ago. Me, the Chief Officer. Captain, who I found out later had a fishing licence and dispensation to sail as Master (Nope, this was not a flag of convenience, but a well regarded open registry). On my first loaded voyage from Singapore to Penang, he told me that I should take out all the ballast we had aboard. “Make it zero,” he said, in a tone that brooked no dissent, and made me wonder, naughtily, as to what he told his wife when he wanted more children.

Puzzled and unaware of his dubious credentials, I asked him why he wanted the ballast out, especially since our GM was low with heavy deck cargo. “We don’t need ballast,” he declared dismissively. “We can get ballast anywhere”.

“Captain, then why do we have ballast tanks?” I asked him.

He cursed in an unfamiliar language. “Make the ballast zero!” he repeated, before stalking away regally.

I re-did my calculations, went against his instructions and kept one double bottom tank full. We were halfway to Penang anyway by now.

A few hours before arrival, the Captain summoned me to the bridge when we were going through a squall that was accompanied by a moderate swell. “She is rolling uncomfortably and is tender,” he told me. “And we have the swell on the beam. Can you fill up some ballast?”

“One ballast tank is full, Captain. I did not pump it out. We should have no stability problems; we do not need to ballast more,” I said, “especially since we can get ballast anywhere.”

“So you did not listen to me?” And, when I remained silent, he added, angrily, “Don’t do it again.”

They gave me command of my first ship soon thereafter. I think it was on the Captain’s recommendation; he wanted to make sure that I could never sail with him again.


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