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Spain builds submarine 70 tons too heavy by putting a decimal in the wrong place
- maskedinvader 13y agothe article doesn't go on to explain more on how this could have happened, I would assume they run some tests on the specs, or some kind of simulations (I am obviously not an expert in making submarines) but considering they are so expensive, wow, amazing. Someone put a decimal in the wrong place and nobody noticed , what are the odds of that happening!
- mpyne 13y agoIt's not as unlikely as you'd think. Even in the U.S. we used to routinely have to put in slop factors to account for contractors that would routinely deliver gear in excess of spec. It wasn't until the most recent SSN class that they were able to finally hold the line against the contractors and sub-contractors... but at least the design itself would have weighed what was expected.
- dm2 13y agoSay they have a CAD model with different types of steel/composites for material. If they select the wrong type of material, or the wrong weight for that material is used, or the thickness of a material is off by even a slight fraction, then an issue such as this could come up. Considering that there are millions of custom parts to a submarine, it's an amazing feat to ONLY be off by 70 tons.
- kryptiskt 13y ago> “Apparently somebody in the calculations made a mistake in the very beginning and nobody paid attention to review the calculations,” he said. Supporting the old software engineering folklore that the earlier a bug is introduced (and the later it is found) the harder and more expensive it is to fix.
- oneye 13y ago> Supporting the old software engineering folklore that the earlier a bug is introduced (and the later it is found) the harder and more expensive it is to fix. I wouldn't call it folklore as there are numerous studies supporting it. EDIT: I decided to crack open Code Complete for anyone who is interested [1]. [1] "Researchers at Hewlett-Packard, IBM, Hughes Aircraft, TRW and other organizations have found that purging an error by the beginning of construction allows rework to be done 10 to 100 times less expensively than when it's done in the last part of the process, during system test or after release (Fagan 1976; Humphrey, Snyder, and Willis 1991; Willis et al. 1998; Grady 1999; Shull et al. 2002; Boehm and Turner 2004)".
- ingve 13y agoThe studies supporting it have apparently been somewhat hard to confirm, a lot of the source material used by McConnell seems to be from secondary sources and self-referential. [1] is a detailed blog post where the author tries to track down the original sources: [1] http://blog.securemacprogramming.com/2012/09/an-apology-to-readers-of-test-driven-ios-development/ http://blog.securemacprogramming.com/2012/09/an-apology-to-r...;
- tzs 13y ago> And a former Spanish official says the problem can be traced to a miscalculation — someone apparently put a decimal point in the wrong place Sloppy reporting. Spain uses a decimal comma.
- akiselev 13y agoThis is an engineering calculation, it may not be guaranteed based on who they're working with and which standard they use.
- deleted 13y ago[deleted]
- fosap 13y agoI'm almost 100% sure engineers use the SI system. (unlike physicist that use a system that seems to be fitting). And the SI system says that 100.000 and 100,000 are the same. The Si system only uses space to group numbers like 12 343,123 12 for twelf thousand and so on.
- akiselev 13y agoMy thought was that anything that used the decimal comma could be confusing when dealing with vectors. However, I wouldn't go so far as to say they use SI across the board. I know aerospace engineering in the US can often switch between imperial and metric depending on which contractors work on the project (this resulted in a mission failure on at least one occassion: http://en.wikipedia.org/wiki/Mars_Climate_Orbiter http://en.wikipedia.org/wiki/Mars_Climate_Orbiter) and it could be the same for other fields.
- damoncali 13y agoYou'd be right. At NASA we could use whatever we wanted. There was no directive to do one thing or another (at least not one I ever knew about) - only the conventions that allowed you could communicate with your peers. Much of the technology we used had evolved over decades. Changing it to metric would have been insane. An interesting line from that wikipedia article: This error has since been known as the "metric mixup" and has been carefully avoided in all missions since by NASA. This is categorically not true, as I worked before and after that, and it had zero impact on the units we used or how we checked them. Most of the time nothing was metric, so it didn't matter.
- patareco 13y agoOther explanation, more in line with the reality of Spanish reality. http://www.thelocal.es/20130520/530-million-bill-for-spains-sinking-submarines#.UZvndKvSNk0 http://www.thelocal.es/20130520/530-million-bill-for-spains-... > The president of the Navantia board has defended the work of the company's Cartagena shipyard and complained of "meddling" by unqualified people. > He explained that it had been reported as far back as 2005 that the development process was not being properly followed and that there was a lot of necessary improvisation due to the addition of new elements at the request of the Ministry of Defence.
- dm2 13y agoThe other key figure is that the entire submarine weighs 2,200 tons. The sub was 3% too heavy and it will cost $14 million to fix, big woop, worse happens 1,000 times per day all around the world.
- rtanaka 13y agoJust to add to that - it's $14 million on top of a $2.7 billion project.
- mdigi 13y agoThis is a great example of an attention whoring headline. When you get into the details there's actually no news here.
- pbhjpbhj 13y agoDidn't they miscalculate a [the?] vital characteristic (buoyancy) on a 2.7B project. Seems news worthy.
- dm2 13y ago"Here is 2.7 billion dollars, build me a super high-tech submarine (with specific specs) and DO NOT make any mistakes." Sounds easy, right? A military contractor going slightly over budget is not news worth, it's database or list worthy at best. Throw the data on wikipedia with the other million projects that had a hiccup or needed more funding, then be done with it.
- muzz 13y agono, that's not the cost to fix the $14M is just for "an assessment of the problem with the S-80 submarine program and the scope of the work that would be required to correct it"
- dm2 13y agook, so $14M + parts and labor
- eridius 13y agoFrom the headline I thought that somehow they had attached 70 tons more weight onto the thing than they wanted (e.g. accidentally made the hull too thick or something). But from reading the article, it seems it's actually they just miscalculated the final weight based on the specs. Their miscalculation had it coming in 70 tons under its actual weight (which is 2200 tons). So the sub was built to spec, it's just the buoyancy calculations were wrong.
- HNLogInShit 13y agoThis is what happens when you use commas instead of proper decimal points.
- rmcastil 13y agoAs I've come to believe its always a communication (or generally human) problem rather than technical. Yet another blunder in line with the Mars Climate Orbiter and the Gimli Glider.
- priv_acy 13y agoIn the aerospace business there is a guy known as the Mass Properties Engineer who gets to rule the project with an iron fist. He is responsible for knowing the estimated, calculated or measured weight of every part on the spacecraft from concept through to launch. It's not a very fun job, but it's very important. Some people actually made careers out of it. You simply cannot get this stuff wrong and not pay dearly for it later. There are reviews, arguments, dealings, and handwringing over all of this. Now, I have no idea if the Spanish sub business runs anything like that, but it surprises me that it apparently doesn't or didn't in this case. It's not like you just let some engineer in the corner calculate the weight and then go build it. This is a systemic fuckup, not a shifted decimal point.
- gmrple 13y agoMy electrical engineering professors were constantly trying to ingrain in us the tendency to estimate the solutions to problems long before solving them. Why? because if you know the ball park solution you'll be able to catch gross errors before they happen. Thus you will be less likely to pull a Homer Simpson at the power plant or end up transmitting too much power from your antenna. I'm thankful to be in an industry where catastrophic failure does not have such harmful results.
- anonymouz 13y agoWithout more details it's hard to say what exactly went wrong, but it is not at all clear that a ballpark estimate would be of any help here: The submarine weighs 2200 tons, and they think it's 70 tons too heavy.
- coldarchon 13y agoActually it is 75 tons too heavy, they stretched the sub out to get more buoyancy but now they have NO IDEA how heavy it really is ..
- damoncali 13y agoThe bigger point is that 70 tons should not sneak up on you. They should have been managing weights carefully throughout the process.
- mikekij 13y agoIs there such a thing as submarine unit testing?
- lmm 13y agoYou can't exactly unit test the buoyancy - the hull is the only part that floats on its own[1], all the other crap you put in would sink. The two need to balance when you combine them, but there's no way to test that at the unit level. [1] Ok technically a few other parts like air tanks would float.
- omegant 13y agoBut you don't have to unit test a radio throwing it to the water. Just sending messages.
- irremediable 13y agoAs I* understand it the only "traditional" engineering field with anything close to unit testing is electronic engineering. Lots of chip or circuit design packages let you automatically test small parts of your design. For mechanical/civil projects, this approach is less common. I think that's partly because of the projects' nature (good luck unit testing a submarine!) and partly because of the engineers being more traditional, and further from the software industry. This said, I can envision some cool things you might do by taking a CAD package and associating some (automatically updating) equations with various parts' critical dimensions. This might act a bit like unit testing. A check of total mass would be another such useful check. * Engineering student with some work experience, but by no means a blooded engineer.
- berkut 13y agoDepends - as it's designed (using GRC's Paramarine - http://www.qinetiq.com/what/capabilities/maritime/Pages/naval-architecture-design-analysis.aspx http://www.qinetiq.com/what/capabilities/maritime/Pages/nava...) you can virtually unit test things like propulsion, stability and buoyancy. Once it's been assembled into one complete system, it's very difficult to do that - individual systems on-board from a systems perspective could be unit tested, but actual physical items - not so much - generally they only find out about mismatches when they try and assemble the warship/sub from different sections (sometimes built by different companies) and they discover their tolerances were off.
- auctiontheory 13y agoGood thing they found the problem before the sub's first voyage underwater.