Talk:Double hull

Bias?
This whole article doesn't read as much like a description of the double-hull ship (this is accomplished fairly quickly), but the longer part of the article just reads as a sale of single-hulled ships. Particularly in light of previous vandalism on the Exxon Valdez oil spill, I added a tag to check the neutrality of the article. Tigerhawkvok (talk) 03:39, 24 March 2009 (UTC)
 * In particular, wording such as "Possibly the most disturbing fact about the double hull is that it does not protect against major, high-energy collisions or groundings which is what causes the majority oil pollution, despite the fact this is why the double hull was put into United States Legislation" fails the "weasel word" test, IMO. Tigerhawkvok (talk) 03:43, 24 March 2009 (UTC)

CONTRADITIONS IN ARTICLE
It has been widely reported after the Valdez spill, and many other non-Exxon spills, that double hull tankers are now required world-wide. If that's the international law, there's nothing I can do about it. A criminal is defined as some entity or person who willfully violates a law, or the spirit of a law. That's not my definition of international treaty law. Arguing against a treaty is fine, but denying the treaty obligations already made is criminal.

The main reasons given at the beginning of the article for double hull ships are totally ignored when the section on oil tankers begins. This is illogical and impossible to reconcile. For example, it is stated that double hulling any ship provides another level of structural strength. Why would we not want tankers to have stronger hulls as well? The explosive gas problem of double hulls doesn't exist on anything but tankers, hunh??? Do you guys know that any ship carries more than enough fuel to leak into its double hull, and any other compartment below deck, regardless of whether it's a tanker or not. If explosions on double hull ships were a problem, they wouldn't do that to passenger ships which all have double hulls, now would they? If explosions are a problem, then provide better ventilation to those areas and more frequent inspections, gas monitors, etc. The reason the industry doesn't want double hulls is because they're not willing to spend the money or maintain the hulls of their ships, and are, technically speaking, criminals.

Imagine if the FAA starting ordering all the mechanics to stop inspecting the wings spars of all airliners since it's too expensive and difficult. Saving bucks is what they're trying to argue for. Double hull ships are considerably more expensive than single hull ships. Recently, a few river tankers broke up coming from the Ukraine headed for the black sea. I think it was 3 or four in one storm with considerable loss of life. Perhaps double hulling would not have helped those wretched sailers. Perhaps it would've. P5g4xn (talk) 00:33, 18 February 2008 (UTC)

Exxon Valdez
Regarding this section, I don't think the word 'ironic' is used properly. --Bigdavesmith 00:39, 27 May 2007 (UTC)

I added a citation tag to the claim that a double-hull would not have prevented the spill. As far as I can tell, although few claim the spill would have been prevented, a report by the Coast Guard estimated that leakage would have been reduced by at least 25% and as much as 60% if the vessel were built with a double-hull. So although the statement is (probably) true, it doesn't seem to tell the whole story, so perhaps a non-neutral tag would be appropriate.

I'm reading an article from late 2000 right now that cites a 25% figure, but if anyone can find something more recent and more complete, that'd be great. Or if someone could explain to me how the article does tell the whole story, that'd be great, too. I don't know much about it, but I've always heard and read that a double-hull would have helped.

http://www.sabew.org/sabewweb.nsf/e0087b5460c4a721862569c2005fa85a/c55130a3122cde2486256ae2005cf6b5!OpenDocument (December 2000)

http://www.adn.com/evos/stories/T99032456.html (May 1999)

http://www.adn.com/evos/stories/EV425.html (originally published 1989)

68.9.205.10 19:53, 31 March 2006 (UTC)

Third opinion
I've got a few points of view on this. First, it often takes someone threatening to delete something to get something done. Bottom line is: Get those sources on, before the facts are gone for good. Sourcing the material in question is hands down the best way to resolve this. That said, perhaps the deleter could move the information to the talk page, rather than completely deleting. This would give time to source, and would avoid loss of information, while still encouraging people to cite their sources. Wrad 06:00, 15 June 2007 (UTC)
 * Thanks for stepping in. You provide a good alternative; for the tagged passages that GWH hasn't provided sources for, I'll start a section on the talk page in case another editor can find them. Alvis 06:06, 15 June 2007 (UTC)

Citation needed
If you are able to provide a citation for passages listed below, please do so, and re-integrate the cited passage into the article:


 * Many in the Shipping Industry consider the Mid-Deck Tanker to be a much more efficient and safer design.

Purpose
Let's not forget that the primary purpose of double hulls is actually not protection, but elimination of dual-purpose tanks. In a single-hull tanker, the tanks store ballast when empty, so a lot of oil washes into the sea just in normal operation. Double-hull oil tankers use interhull space as ballast tanks.

Besides, there are chemical tankers, with sufficient space to actually prevent spills. Double-hulls, if using corrugated bulkheads, can also have "clean" tanks, easy to wash, for multiple products. So I suggest we find some source and add this info. Double hulls aren't just a safety measure. CP/Mcomm |Wikipedia Neutrality Project| 21:39, 14 June 2007 (UTC)


 * No, the reason for double hulls is to protect. Tankers haven't used multipurpose tanks for many decades, since the oil released by doing so became controversial in the 70s.  IMO regulations in the 70s and 80s required separate ballast and cargo tanks for oil tankers; the Exxon Valdez, for example, had port and starboard ballast tanks along half of the hull sides, alternating with cargo tanks.  Georgewilliamherbert 22:32, 14 June 2007 (UTC)


 * In part, this was a reason. However, it was not protection, but tank separation requirement which made double hulls practical [BTW, regulations differed quite a bit between countries]. A major issue of double hull structure is wasted interhull space; its use for the imminent dedicated water tanks was the major push making double-hull oil tankers economically feasible enough. Protection was a factor, but not the only one. Where it really is, e.g. chemical tankers, the 20% double hull width standard is used (40% sides only). In oil tankers, only the requirements for ballast tank size determine the double hull width. CP/Mcomm |Wikipedia Neutrality Project| 12:16, 16 June 2007 (UTC)


 * Am I missing something? Double hull designs are used in Bulk and Container vessels as well.  Sure there is all this talk of protection, but tankers aren't the only vessels carrying large amounts of fuel/heavy oil.  —Preceding unsigned comment added by 211.5.250.117 (talk) 02:52, 27 October 2009 (UTC)

Howdy all

Quick note - (I'm new to this!) I note that the text says 'double hulls are significantly safer'. I'd like to see an authoritative statement for that. All the professional maritime sources I've ever spoken to are pretty unanimous that double hulls make things WORSE! There's even a study to that effect from the European Martime Safety Agency.

Cheers

Jimmec (talk) 13:30, 16 January 2008 (UTC)
 * Sorry I didn't see this years ago, but could I ask where that study can be found? Here's what I found from the EMSA:
 * "For low energy collisions and minor groundings, it has been demonstrated that the double hulled tanker is much less likely to spill oil than a single hulled tanker. As the majority of accidents fall into this category, the initiative to phase out of single hulled tankers and introduce mandatory double hull structural arrangements for tankers is now well advanced."Double Hull Tankers: High level experts panel report]
 * Apparently they are harder to inspect and more prone to corrosion. There is a "thermos bottle effect" in that warm cargoes stay warm and maintain an environment between the hulls conducive to corrosion.
 * 71.41.210.146 (talk) 21:32, 31 March 2010 (UTC)

Question
Is double hull used in merchant ships? —Preceding unsigned comment added by 210.94.110.108 (talk • contribs) 23:12, 2 February 2008 (UTC)

the original write up is true. Double Hull vessels do not protect against high energy collisions. —Preceding unsigned comment added by 202.154.168.142 (talk) 07:00, 16 December 2009 (UTC)

Convert Single Hull to Double Hull
Dear All,

I would like to ask some question about benefit convert single hull vessel to double hull vessel.In term of technically I am also not recommended by the way if the job can make profit we can consider.Now I have problem to discus whether we need to convert to the latest MARPOL tanker or just buy a new one.

From My Technical Opinion :

- This converting job still have many job to be done. - The previous hull plate to be change - The capacity of that's vessel less - Strengh of the vessel need to analise same like to design the new design or just get the sister ship

If any relevant description we can disscuss.Thanks —Preceding unsigned comment added by 219.93.72.54 (talk) 05:06, 3 November 2008 (UTC)

Double Hull on Passenger Ships
Hello everybody,

I have worked on cruise ships and ferries, all of them built after 1990 and none of them has a double hull. I am hereby referring to the sentence "Double hulls or double bottoms have been required in all passenger ships for decades as part of the Safety Of Life At Sea or SOLAS Convention. " I have checked my SOLAS and couldn't find any requirement for a double hull on passenger ships. It would be nice if this could be referenced to the proper SOLAS chapter and regulation. Many thanks —Preceding unsigned comment added by Jeanclaudelennon (talk • contribs) 18:00, 25 May 2010 (UTC)


 * Solas Chapter II-1 Regulation 12
 * Quoting from pp 71 of the 2004 combined base text plus amendments in force at that time:

Regulation 12 Double bottoms in passenger ships 1 A double bottom shall be fitted extending from the forepeak bulkhead to the afterpeak bulkhead as far as this is practicable and compatible with the design and proper working of the ship. .1 In ships of 50 m and upwards but less than 61 m in length a double bottom shall be fitted at least from the machinery space to the forepeak bulkhead, or as near thereto as practicable. .2 In ships of 61 m and upwards but less than 76 m in length a double bottom shall be fitted at least outside the machinery space, and shall extend to the fore and after peak bulkheads, or as near thereto as practicable. .3 In ships of 76 m in length and upwards, a double bottom shall be fitted amidships, and shall extend to the fore and after peak bulkheads, or as near thereto as practicable.
 * It's highly unlikely that your ships didn't have full double bottoms, whether you were aware of it or not. The convention doesn't require a full double hull, to my knowledge.  Georgewilliamherbert (talk) 18:19, 25 May 2010 (UTC)

Hello,

Thank you for your contribution. Of course the ships I've been working on have a double bottom. However they don't have a double hull, which is different. In fact, the text cited above does not require a double hull on passenger ships, only a double bottom. I suggest to remove that sentence from the article as it may cause misunderstandings. Jeanclaudelennon (talk) —Preceding undated comment added 18:30, 25 May 2010 (UTC).

Da Vinci
The Da Vinci article says that he invented the double hull, yet this is not mentioned in this page. Is it false, or should we give an old man his due? 124.168.163.223 (talk) 10:52, 4 May 2011 (UTC)


 * The first ship with a double bottom was Brunel's SS Great Eastern — Preceding unsigned comment added by 95.145.115.91 (talk) 10:27, 20 August 2016 (UTC)

Merger proposal
Extensive overlap of content,. Tagged as unsourced since 2008; if nobody's bothered to find sources in 12 years, it's unlikely they ever will. -- RoySmith (talk) 16:51, 14 November 2020 (UTC)