Talk:Oil tanker

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Supertanker

Please, do not redirect Supertanker to this article. It makes a hell in iw. Not all supertankers must be necessarily oil tankers and not all oil tankers are obviously supertankers. Make a special article for Supertanker. It does not have to be a long one. Thank you very much! Miraceti (talk) 13:20, 30 December 2008 (UTC)

Engine pollution

Besides the possible pollution from spills, the gasoline engines also cause pollution (always). This, escpecially as they often run on less-refined oil, this btw is also the case with other large vessels. Add section info and add the same info in the other large vessel articles (container ships, bulk carriers, ...) —Preceding unsigned comment added by 91.182.175.116 (talk) 13:58, 30 July 2009 (UTC)

Miscellaneous

In the Ore-Bulk-oil Carried section, the link labeled "ballast voyages" linkes to sailing ballast, which does nothing to explain what a ballast voyage is. —Preceding unsigned comment added by 174.96.89.173 (talk) 18:08, 13 May 2010 (UTC)

How long does it take to fill one up ?

I'm curious as to how long, say for a small, or a medium, or large one. And come to think of it, how long it takes to empty her too. Days or weeks or months ? Thanks ? --Jerome Potts (talk) 02:02, 29 September 2010 (UTC)

There are several variables. Loading is generally quicker than unloading, because it uses shore-based pumps which can be arbitrarily large. Unloading is almost always done by shipboard pumps. Also, more viscous products (i.e. crude oil) are harder and slower to pump. For example, one can expect that loading crude in Alaska is slower than in the Arabian Gulf, because colder product is more viscous. One thing that is very variable is how many lines are being used. If you're pumping through three 12-inch hoses, it will be approximately three times as fast as pumping through one 12-inch hose. Another variable is "static head", roughly the pressure you are pumping against. If you're pumping 5 miles uphill to a full tank, its slower than 500 yards to an empty tank. All that said, a discharge of product (like gasoline) on a 30,000 DWT tanker might take 8-12 hours and a load would might take about 6 hours. I've personally never has a discharge take more than 24-hours. Cheers. Haus^Talk 02:35, 29 September 2010 (UTC)

Thanks a bunch. But lucky me, i am wondering about the handling of crude oil. So thanks for the detail on the factors that affect the operation, but perhaps we can look at it from another angle : how long do ship operators usually expect, and tolerate, a loading (of crude) to last ? For, say, a VLCC. Perhaps there is a rule of thumb somewhere, or an average ? --Jerome Potts (talk) 04:24, 29 September 2010 (UTC)

Your question got me curious, so I sent an e-mail in to an old VLCC skipper. I expect he'll say, on average, around a day. In reality, the charterer and the port look at all the variables and come up with an estimation. After an hour of moving cargo, the chief officer and port PIC compare their measured flow rates and amend the schedule. The flow rates and ETC are generally re-calculated hourly after that. If the port, the operator, or the charterer is responsible for the cargo operation taking longer than it should, monetary damages can be assessed. Anyway, when I get a response to the e-mail, I'll post it here. Cheers. Haus^Talk 05:07, 29 September 2010 (UTC)

Thanks ! This is definitely interesting. --Jerome Potts (talk) 23:22, 29 September 2010 (UTC)

The answer I got was "almost never more than 24 hours for a discharge." Keep in mind, though, there are probably a few terminals somewhere out there with bad conditions/design/technology where it takes longer, but a VLCC would be more likely to run between hi-tech ports. Cheers. Haus^Talk 00:15, 30 September 2010 (UTC)

Thanks again. What i am after is an idea of time for a fill-up from an offshore rig ; this has been helpful. --Jerome Potts (talk) 18:21, 30 September 2010 (UTC)

Ligthering grain?

I have never heard of grain being carried on a tanker going for scrap as it would need far too much work to get the tanks clean enough for grain, far too much work to load the grain and far too much work to discharge the grain.

The picture looks like a gang of tank cleaners leaving the vessel — Preceding unsigned comment added by Thinfourth (talk • contribs) 17:22, 5 March 2011 (UTC)

You're right in that it was a tremendous amount of work on both ends of the trip. See File:Lightering-grain-from-tanker.JPG. Haus^Talk 03:41, 11 March 2011 (UTC)