Saturday and the Happy Banana

 Well, it's Saturday, God turned the heat on, and we're loaded deep here at the HQ. 

       Today was not looking like a good day. The first heat wave of the season is here in Satan's Anus 

 New York, and the weather is actually more moderate by far at my house in South FL. Sadly, I am not at my house in South FL, I'm here in Sodom New York. 

 The original plan was for back-to-back cargo discharges to two different ships, both getting a modest sup of heavy oil and diesel oil, which would take up my entire day, and given the volumes in question, requiring me to be out on deck broiling in the sun and stop-gauging the tanks for much of that time. 

       It's a funny thing about oil tank vessels. Electronic gauging systems are not that accurate. Not accurate enough, anyhow, in dealing with a high-value commodity like oil.  Oh, we're no paragons of accuracy in the trade, mind; nobody raises an eyebrow at a couple of barrels difference or a few tons here and there. What's 10 grand USD between friends, right?  Fun fact, after completely sucking the tanks dry when I was carrying gasoline or diesel 15 years ago when homeported in Philly,  we used to be able to fill up everyone's vehicles with leftover gasoline from the pipelines and sumps in the tanks. Just siphon it out with a whiz-bang pump (a Wilden pneumatic diaphragm pump).  This ended of course when some greedy shithead started filling up barrels in the back of his truck to take home, and got hisself pulled over carrying explosive hazmat in the Chesapeake Bay Bridge tunnel, which frowns upon things that go bang on their property.   I bet that guy is probably just getting off probation now,but for a time it was nice. Whoever happened to be at the dock that day got topped off. The oil left in the pump sumps in the tank and in the pipelines is either written off if it's not something that can be measured, or vacuumed out and removed forcibly by a tank cleaning barge if the next cargo going in that tank is not compatible with the one before.  You can ignore a barrel or two of diesel in 50,000 barrels of gasoline, but you can't ignore a barrel or two of gasoline in 50,000 barrels of diesel. In one case, the engine will run smoother. In the other, the engine will blow up, and has been known to blow ships in half in fact, when gasoline gets in to heavy fuel oil. burnt by the ship's engine. 

      So yeah, tank depth gauging is not accurate enough for what we need, and requires constant recalibration just to be a rough guide. We use multiple redundant systems to be sure we have what we want for oil, but all boils down to the Mark 1 Eyeball being the most accurate arbiter of volume. Every 1/8 inch in every tank has a corresponding volume associated with it, and as pipelines, internal framing, pumps and the shape of the hull vary, every tank has different values at a given height off the bottom. This is measured accurately enough that it's not unusual to find 1/4 or 1/2 inch difference of the total height of the tank itself, from bottom to top between port and starboard tanks next to each other. Tank vessels are built in blocks, and the blocks are assembled level, not plumb I think .I always was satisfied with a 1/8 inch plus or minus error in measurements for the few skiffs I've built, but model ships which tend to be about 4 feet long, of which I've built a few, they've got to be within a 1/16 where it doesn't matter and a 1/32 where it does. So I guess, when dealing with 300 feet of hull, a quarter or half inch of warp in the steel is what they have to deal with over long runs of welded material distorting. At any rate, hand measuring oil depth in the tank using a measuring tape with a weighted bob on it, or a sealed gauging gun (with a window for you to see the tape and  a hand crank to lift or drop it so you don't let vapors out) still means the eyes make the final measurement. 

           There are flowmeters that, when calibrated and adjusted for density of the oil, are now quite accurate. This was not the case in the past. In places in the world where fueling is a matter of lying, negotiating, bribing and fighting and the numbers don't matter as much as the skill of the parties involved in lying and negotiating, a not-super-accurate flowmeter isn't a big deal.  Here, we care, and accusing someone of being the scion of a long proud lineage of lying whores,  well, I will likely consider knocking such a man over and stomping on his head until it either changes shape or he apologizes politely with my size 12's testing the load bearing capacity of his temple. 

 So no, my employer did not see fit to outfit us with flowmeters and a criminal defense lawyer on retainer.  It would be nice, though, set up the job and sit in a cool cargo office and watch numbers tick by. But no, instead we hover over tanks, and with a gauging tape and bob, chase the surface of the oil down and shut the valves when we achieve the proper depth to take a certain volume out of that tank. Then repeat in other tanks, the volume being dictated by the total amount desired, and the tanks chosen based on keeping hull stress down (leaving some tanks full, some empty and some partially full puts strain on the keel. The hull will flex based on the weight of the oil in the tanks. We want a "Happy Banana" with the keel midships no more than a foot deeper in the water than the keel at the bow and stern. When empty, the keel is a "sad banana' with the bow and stern about 6 inches lower in the water than the midships. What we don't want is a VERY happy or sad banana, because then you break the keel.