Originally posted by: Fern
Originally posted by: GroundedSailor
Originally posted by: Fern
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I have been on ships carrying crude / gasoline / diesel / naphtha and there is no way we would allow any source of ignition on those ships. The biggest danger on any ship (not just tankers) is fire, so those concerns are real and justified.
I can understand concerns with naptha & gasoline.
I do not understand concerns with diesel or crude. Diesel is used in boats and ships for the very reason that it is not explosive.
I tried your links but had trouble with them. Can you please explain why you think crude and diesel are explosive.
Fern
Among all the various petroleum based products carried on tankers crude oil is probably the most dangerous. Crude contains everything from the heavy stuff like waxy sludge to all the fines including naphtha and spirits. The flash point of crude is all over the place. At least with products you have a defined range for each product.
In the seventies there were many incidents of explosion on large crude carriers (almost all when they were tank cleaning or empty) which were analyzed and they realized that the high pressure water jets used to clean the tanks were building enough static to cause explosions in the tanks as the tank atmosphere was always within the flammable range of some component of crude or the other.
Oil tankers are broadly divided into 2 categories - crude carriers (or black oil carriers) and product carriers (white oil carriers). Product carriers will typically carry one type of product at a time. Or if they are carrying 2 or more different products, these are well segregated in different sets of tanks. So, on product carriers you generally know the limits of what you are dealing with.
After the industry better understood the cause of the explosions it became standard practice to inert cargo tanks on crude ships. Use of inert gas on product tankers is a recent phenomenon.
Edit:
While diesel (called
gas oil in the industry) is not as volatile as naphtha or gasoline, it still has a flash point of around 130 - 140 deg F. Diesel is used on ships for generators and other aux engines. The ships main engine uses Heavy Fuel Oil which has to heated to about 200 deg F before it is injected into the engine. This is not practical for generators which is why diesel is used.
Having said that, using these fuels to run the engines and carrying them as cargo are 2 different scenarios. When carried as cargo the risks are much higher which is why the standard industry practice of taking precautions to avoid any sources of ignition. Firearms are a horrible idea on tankers. I know I would not be willing to sail on a tanker which carries men with firearms.