Talk:Supertanker

NPOV comment

With respect to the decision to remove the reference to the tanker Prestige, I originally included that to highlight the enviromental impact of tanker accidents, both here (the US) and abroad. In my opion, it belongs in the article because of the effect it had on the European Union, even though human error was not a factor in the crash. And I apologize about the article coming across as an eviromental rights platform, instead of a nuetral point of view. I will have to pay more attetion to that in the future. Tomstar81

Gravitational pull?

I heard somewhere that because of their enormous mass, super-tankers actually correct for their own gravity pull when navigating close to each other...is this true?

No, this is very unlikely. Even a metre apart the gravitational attraction between two super-tankers is quite small. A much bigger issue, and I believe they do have to allow for this when coming into harbour, is that between two large vessels there will be an area of calmer water. The additional force of waves on the outside side of the two vessels compared to the inside (calmer) edges, pushes them together. BruceRD 22:58, 2 September 2005 (UTC)[reply]

You can try to think about Bernoulli's equation. Gravity is neglectable. Miraceti 16:08, 5 December 2005 (UTC)[reply]

supertanker?

I am a tanker broker and came across this page - good work people, just a few comments for you to ponder:

1. the word "supertanker" is not used at all in the shipping industry - size specific names are used, ULCC, VLCC, Suezmax, Aframax etc, supertanker tends to be a catch all media term

2. the picture of a tanker at Istanbul labelled as a "supertanker" cannot be one by the articles own definitions as a 250,000 dwt ship cannot pass through the Bosphorus & Dardanelles

3. as the Jahre Viking has now been converted into a FPSO does it belong as the "biggest tanker" although FPSO's have tank capacity I wouldent describe them as tankers - they are floating oil platforms made from converted tankers

US $0.02 of the cost of gas at the pump

Heh? Would be any American so kind and explain this more precisely? Information is useless without specifying an amount of gas with this added cost. Thank you. Miraceti 16:06, 5 December 2005 (UTC)[reply]

That information was according to an episode of "Modern Marvels", a history channel program. The show stated that the cost od shipping oil in supertankers translated to an added cost of only two cents at the pump. TomStar81 04:36, 26 August 2006 (UTC)[reply]

They probably mean $0.02 of the total cost for a gallon of petrol is because of tanker shipping costs. —The preceding unsigned comment was added by 70.116.13.211 (talk) 14:28, 8 April 2007 (UTC).[reply]

Map link comments

I cut this:

Links to Google Maps don't work with old browsers (you need IE 6.0+, Firefox 0.8+, Safari 1.2.4+, Netscape 7.1+, Mozilla 1.4+, Opera 8.02+)

because I don't think it's necessary. It evolved from someone adding in a complaint about the links and Opera. Just putting it here in case someone thinks it's valuable info. --Howdybob 23:07, 8 July 2006 (UTC)[reply]

Some points ...

I'm a maritime journalist and I'd like to back up the tanker broker. It's good to see people taking an interest in shipping.

'Supertanker' is a term unused within the shipping industry.

Second, the ref to double hulls needs a little expanding IMHO. Expert opinion is that double hulls do not make tankers any safer, if anything, it makes oil spills more likely.

Thirdly, one of the other posters mentioned the Prestige. There was in fact significant human error ... but not by the crew. Evidence which has come to light since the demise of the Prestige shows the fault for the spillage largely falls on Spanish govt officials who ordered the tanker back to sea when it should have really been given a place of refuge

That's it!

Query on some points

"Expert opinion is that double hulls do not make tankers any safer. if anything makes oil spills more likely" - Reference? Indeed there are no perfectly safe way to transport oil. A double-hull does indeed make a vessle more safe, minor damages that could lead to complete disasters may be prevented, as the vessle does not start to leak oil immidiately if the outer hull is damaged, while a single hull ship getting similar kind of damage runs high risk of sinking, and will for sure leak oil under such circumstances. Thus "the comment does not make a vessle any safer" is obviously not a correct statement. But indeed, not even a double-hull can totally prevent a ship from braking and sinking. Oil has to be transported in some way as long as it is used, right? But there is no totally safe way to transport oil. It is more economical the larger vessels that are used for oil transportation, but simultaneously the handling of the huge vessels is difficult and they need longer distances to stop because of their mass. But it is unrealistic to beleive that any oil tanker, or any other way of transportation would be perfectly safe. Based on what would "oil spills be more likely for double-hull vessels" ? - The only reason would be human neglect. The amounts of oil ending up in the sea must be minor issue compare to the environmental protection a double hull can do by by preventing us from just one serious accident... "Be reasonable"

Work on the Supertanker

I was wondering the job specifications to operate or work on a tanker. What type of hours, wages, or requirements you need to meet in working on a tanker. I am guessing you need a degree in engineering in order to be even considered to work on one. But then again, you will probably need technicians, navigators, crew, cooks, and other such members to operate the behemoth. Is there any type of website or company that I can call that will answer my questions? —The preceding unsigned comment was added by Cire288 (talk • contribs) 05:28, 22 February 2007 (UTC).[reply]

Some Further Points:

Some Further Points: Hi, this is the maritime journalist again, responding to the anonymous poster who queried the safety status of double hulls.

"Expert opinion is that double hulls do not make tankers any safer. if anything makes oil spills more likely" - Reference?

Reference: mostly personal conversations with class surveyors and maritime officials. For instance, one senior maritime official remarked to me over lunch that "people seem to think that an extra foot or two of air stopped by a little plug make vessels safer." For published works, you can check out: "The Tankship Tromedy" by Jack Devanny is an excellent book on the flaws of tanker design.

"A double-hull does indeed make a vessle more safe" and subsequent comments. As for double hulls making tankers safer, that's doubtful. Collisions at a low speed wouldn't necessarily damage the vessel. Collisions at a greater force would still have to rupture the internal oil tanks and cause the oil to spill. There is a physical force called 'hydrostatic balance' which basically refers to the (strong) tendency of oil and water to repel each other. Expert opinion (Jack Devanny again) points out that hydrostatic pressure and elevated tanks within tankers is more than adequate to contain an oil spill in the event of a low impact collision. It is correct to say that a double hull tanker is no more safe than a single hull tanker. It's a bit strong to say that Double Hulls are redundant - they do have some value in low energy collisions. But there are strong reasons to believe, as I'll explain below, that double hulls are actually more dangerous.

"minor damages that could lead to complete disasters may be prevented, as the vessle does not start to leak oil immidiately if the outer hull is damaged, while a single hull ship getting similar kind of damage runs high risk of sinking, and will for sure leak oil under such circumstances"

Very much the opposite. A single hull is more easily inspected and maintained (remembering also that oil is not carried within big void spaces within a tanker, it is carried within big tanks within the tanker) then are double hulls. Plus the struts between the skins of a double hull are subject to hogging and sagging forces (the tendency to make metal bend down at the ends and up in the middle (hogging) and down in the middle and up at the ends (sagging)) whereas these forces are non-existent in the case of a single hull tanker. Double hulls also carry a greater risk of explosion than a single hull. Crude oil is not flammable - the gas from it is (if you don't believe me, trying getting some crude oil and dunking a lit match into it a speed. The match will go out). Double hulls have void spaces between their skins, whereas single hulls do not (because they don't have two skins). Gas collects within the void spaces and so must be pumped full of inert gas to prevent explosion. None of this applies to single hulls ships.

Owing to the greater use of materials involved, greater hogging and sagging forces, greater likelihood of explosive gas/air mixture building and greater difficulty of inspecting and maintaining double hulls when compared to single hulls, it is likely that double hulls are more likely to spill oil than single hulls. Tankship Tromedy by Jack Devanny is an excellent book on tanker design. You can also read "Double, double toil and trouble" in Fairplay International Shipping Weekly, 23 Jun 2005, which gives further detail. You can also read criticisms of Double Hulls in a document published by the European Maritime Safety Agency. It's called Double Hull Tankers: High Level Panel of Experts Report (2005) at http://www.emsa.eu.int.

Not all Supertankers must be oil tankers

The redirect is not a good idea. What about a short article about supertankers? Miraceti (talk) 21:59, 12 August 2009 (UTC)[reply]

Are there any non-oil supertanker class vessels? There are other bulk liquid cargo hauling ships, but not of this size that I know of... Georgewilliamherbert (talk) 22:22, 12 August 2009 (UTC)[reply]

Are there any non-shuttle spaceplanes? It is very similar to this case. There is currently no non-oil supertankers but this is not the most important thing. Redirecting the general term to the more specific makes problems in interwikis and understanding of the term itself by readers. Miraceti (talk) 10:21, 21 August 2009 (UTC)[reply]

They're not functionally generic to specific - they're functionally synonyms, as there are no non-oil supertankers out there that I know of. Main article at the most common name for them, redirect from other common names is the manual of style solution for that. I believe this is all normal and correct. Georgewilliamherbert (talk) 01:31, 22 August 2009 (UTC)[reply]

And to answer your rhetorical question - yes, there are multiple non-Shuttle spaceplanes. Buran (spacecraft), X-15, NASA X-38, MAKS space plane, Mikoyan-Gurevich MiG-105, Boeing X-37, Boeing X-40. Buran, X-15, the MiG-105 subscale demonstrators all flew in space. Georgewilliamherbert (talk) 01:37, 22 August 2009 (UTC)[reply]