Thursday, January 31, 2013

FTV 1/31/2013 Bunkering outside of Puerto Rico

T.S. Kennedy was at a standstill. We needed to fuel up, so the deckies worked on anchoring the ship so the bunkering process could take place. "Bunkering" is the process of taking on fuel. We were just outside of our port at San Juan. During the bunkering process a barge, that has fuel in it, comes up to the ship. They send up hoses, approximately six inches in diameter, and hook it up to a manifold that leads into our fuel tank.

The fuel we take on is heavy fuel; very black and as thick as molasses. In order to pump it up into our tank, it has to be heated up to 110 degrees; this way it flows more easily. If the heaters in the barge weren't working, it could take a very long time to get the fuel to move. So, if a situation like that happened in cooler water, the fuel might not have been able to flow at the necessary rate to get our voyage back on the move. The marine engineering cadets had a big part in the bunkering process.

They would take tank soundings by dropping a measuring tape into the tank in order to determine how much liquid is in the tank. The other measurement they use is to determine how much air is in the tank (instead of checking the amount of liquid) where they drop a little cone attached to a string into the sounding (pipe that leads to the fuel tank). Taking both of these measurements allows them to ensure that we take on the right amount of fuel and prevent overflow. The engineers have to keep "sounding" the tank every so often. They also take fuel samples to make sure that the fuel we take on is good quality fuel. They are also constantly checking for leaks, just in case. When we are bunkering, there is absolutely no "hot works" (smoking, welding, etc.) allowed! The process went very well. It took approximately nine hours for the fueling to be complete.

After taking on our pilot at 1800. We are now on our way to our next port! Exams are coming up, and then liberty in Montego Bay!

Why does the temperature of the fuel matter? Because liquid particles can move past each other, they can flow. This is very important when transporting liquids from one place to another through pipes or water ways. VISCOSITY is a measure of the resistance of a liquid to flowing. The viscosity of a liquid increases as the temperature of a liquid decreases. This means that the colder the liquid the more difficult it is for the liquid to flow. In the diagram, the chilled red liquid is flowing very slowly. It flow is so slow that the liquid is moving out of the glass like a thick blob of ketchup. The viscosity of a liquid decreases as the temperature increases. This means that the warmer the liquid, the faster a liquid can flow. As the viscosity of a liquid increases, the thicker is the liquid and the more sluggish is it ability to flow.

Try these activities
Comparing the viscosity of oils 
Behavoir of fluids
Is it a liquid or a solid?

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