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#106
10-29-2008, 12:12 AM
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| discussion quality level LyndonJ, i built and dived my first concrete submarine (a 1 tonner) at the age of 15 - i built a 20 tonner weekend concrete submarine yacht prototype in the mid nienties and tested the concept of submarine yachting extensivly for many years - this is the reason why i get the funds to make the 200 tonner submarine cruiser i am working on now - i made my homework - and i did my testing and prototyping. I do base things on step by step realization - not on fantasy. The question of orbital wave action ... well i think you should step away from theory and ask a surfer why it is safer to dive below a wave than stay on surface (no-it must not be 300 ft - a few feet is sufficient) ... collision .... this hollywood stuff - will not happen in submarine yachting practice . laughing - flatulence - nightmare - nuclear power plants - please keep the discussion here on a certain quality level or i am out - i do not have a lot of time to step into low level discussions - i am a busy man - i do provide working submarine yachts. Cheers, Wil www.concretesubmarine.com |
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#107
10-29-2008, 05:39 AM
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| Wellmer It’s not much to ask for some sensible answers from someone who claims expertise. To me at least you appear to have some very questionable reasoning and a concerning lack of knowledge. If you promote yourself and your concept on a public forum you can expect some searching questions and should be prepared to discuss it properly. You can then improve your knowledge arguments and design through such exchanges. I think the nuclear power plant argument is about similar issues and is valid. Safety in subs is due to expensive quality equipment professionally designed It is also due to stringent screening and training of crew. You cannot argue that something is safe without considering why that is the case. One atmosphere subs can become death traps very quickly, small subs are very much more dangerous than big ones since there is little or no redundancy. Collisions must be considered and nets cables and wreckage are a constant threat to immersed vehicles. There are experienced experts in this field that you can learn from too. What are your safety contingencies ? for example what does the operator do if entangled in a discarded trawl net? The surf argument is rubbish, breaking wave energy is not the same as orbital effects. Wave orbital effects are deeper than you would like to believe. Your efficiency argument is questionable, Your claims of low maintenance are questionable, your piracy argument is questionable, you discount collisions as a danger, it all appears a bit hair-brained to promote such a vehicle as a common yacht. Here’s a simple laymans guide to submarines for you from a very reputable source, a very quick search produced this: http://www.navy.mil/navydata/cno/n87/faq.html look at 21 and probably the rest of it too. Since it appears you are frighteningly uninformed. |
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#108
10-29-2008, 10:20 PM
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Hello LyndonJ, Maybe my reaction is sometimes a bit like a dentists reaction when receiving fatherly advise from a brain surgeon on teeth extraction... Finally i am the guy who has built, and sailed, and tested concrete submarine yachts since the mid nighties - you really should have built a couple of concrete yachts to to treat me as you do - i am prepared to discuss properly but not willing to repeat a emotional discussion with any bonehead that comes my way. Many things you are saying are true - for military subs - but not very relevant for submarine yachts among those are the collision, the collision of the nuke boat with the japanese ship was due to the military style blow out surfacing - would never happen in a sub yacht that comes up with a speed of inch per minute similar to a scuba diver - what comes first out is a tube with a diveflag and a flash while the hull is still 4m down - anybody who do overrun that is so blind that he would overrun a oil tanker too. The entanglement issue is in any submariners mind since a perry sub entangled his in a wreck - it was a design asking for entanglement that never should have operated so close to a wreck in first place ... I would recomend a ROV with a cable cutter on board of a submarine yacht that plans close encounters of that kind. Not every expert that feels expert is an expert - give me your field of expertise i will listen carfully what you have to say - as long as your statement is inside your field of expertise. You seem not to be much of an expert to me on the topic of how deep you must go to be protected from wave force - a surfer is - at least at my planet. I ensure you a few feet make a BIG difference - it is not gradually down to hundreds of feet as you suggest. Orbital action is relative theorical and irrelevant what is relevant is breaking force - at some level you seem consient of that so why the misslead ? Everything in life is questionable...my expert status - yours - we do not get anywhere this way - so what i do is setting facts building and testing the submarine yachts i am talking about. Thanks for your help pointing me to a military link to get informed about civil submarine yachting - you could point me to a rocket destroyer link to learn about sailing yachts or a battle jet link to learn about ultralight airplanes... frightenly uninformed ? - the truth is always in the viewpoint... let's get to a social adequate envelope here...you owe me some respect dude... ...now that we have done the social biting - can we do some real brainwork please! Cheers, Wil |
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#109
11-12-2008, 08:23 PM
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| hi guys, i'm a structural engineer claiming zero expertise with concrete submarines. so i'll start with darn it, why didn't i think of this! what a great application for the material. neophyte queston. is the batch mix comparable to say a pool mix? high strenght, shotcrete application? |
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#110
11-17-2008, 12:25 AM
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| Once again, arrogant egos prevail, ignorant dialogue abounds, and productive banter ceases. Idiots. |
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#111
11-18-2008, 08:15 PM
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| concrete mix Quote:
I like to work with normal concrete in cast application due to the "foreseeability" of the results. I have been looking at shotcrete - what i am not so comfortable with - is that shotcrete depends so much on the personal skills of the "nozzleman" - the other point is, that it seems quite difficult and time consuming to build up thick walls of uniform quality. Cheers, Wil |
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#112
11-18-2008, 08:39 PM
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I have 2 structural engineering questions. 1) In a concrete sub with the characteristics of my hulls (4,6m outer Diameter - 34cm wall thickness) would you expect Buckling to be a problem or a expected failure mode? 2) If you take such a hull to some 30m depth as we are planning - what percentage of the real concrete strength do you use? How does this safety factor compare to typical safety factors in high rise building? Thanks, Wil |
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#113
11-18-2008, 09:44 PM
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| Hey guys, Thought I'd chime in on the shotcrete idea... with an emphatic NO! I've been involved on a few projects where, for various reasons, someone decided that shotcrete would be a good idea. I also had to put up with a concrete canoe team attempting to build their boat with it once. It's a wasteful, difficult and messy system that is very dependent on the operator's skill. Enormous voids can easily become entrapped with no visible evidence if it isn't constantly monitored. I would strongly advise against using shotcrete for anything other than a swimming pool or foundation wall. I can think of a number of ways to make a concrete mix that would work well for a c-sub hull. If I were building one I would likely look at designing the formwork to handle full liquid head. Then ask one of the more competent ready-mix firms to design a self-consolidating (SCC) mix for C-XL exposure class (see CSA A23.1), probably around 40 MPa (depending on structural calcs). By the time the prequalification trials are put together, chloride permeability tests done, etc. the up-front costs will be a bit higher than a conventional mix, and of course the mix itself will be a bit more expensive. But a good SCC mix with w/c ratio in the 0.3-0.4 range eliminates the need for vibrators, achieves near-perfect adhesion to the rebar, and if your forms are good will virtually eliminate honeycombing. (At one site I was at last year, we did a 400-metre pour with only two guys up top: one on the pipe and one on the pump controls. The same pour with conventional concrete would have taken twelve men, if it were even possible with the rebar densities we had.) For complex shapes I think it would be well worth the cost, especially since the concrete mix itself will probably be a relatively small component of the total cost of the c-sub.
__________________ - Matt Marsh - Marsh Design (small craft blog and designs) |
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#114
11-20-2008, 12:38 PM
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| Ben Franklin sub & Gulf Stream drifting project Been away from the forums for quite awhile and missed this subject of submarines. I do remember being quite fascinated with the Ben Franklin Gulf Stream Project as I was involved with submarines at the time, and also very interested in the field of oceanography. I've see it mentioned a few times on this subject thread, but no direct web-links to the subject....so I offer a few here: http://www.sub-find.com/historical.htm http://www.bosunsmate.org/benfranklintour.php http://www.unexplainable.net/artman/...cle_1006.shtml "In mid-July of 1969 the whole world was focused on NASA's Apollo 11 moon landing. But some people at NASA were focused on something else. On July 14, just two days before the Apollo launch, the PX-15 deep sea submarine Ben Franklin was towed to the high-velocity center of the Gulf Stream off the coast of Palm Beach, Florida. With NASA observer Chester "Chet" May on board, the sub descended to 1,000 feet off of Riviera Beach, Florida and drifted 1,400 miles north with the current for more than four weeks, reemerging near Maine. In addition to studying the warm water current which flows northeast off the U.S. East Coast, the sub also made space exploration history by studying the behavior of aquanauts in a sealed, self-contained, self-sufficient capsule for NASA. The mission is the focus of a program airing on the Science Channel" Lots of other reference sites: http://seawifs.gsfc.nasa.gov/FRANKLI...lin_links.html Popular Mechanics article: http://seawifs.gsfc.nasa.gov/FRANKLI...mechanics.html |
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#115
11-21-2008, 08:29 PM
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#116
11-24-2008, 12:06 PM
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#117
12-05-2008, 02:30 PM
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| http://www.underseavoyager.org/ info@underseavoyager.org When Scott Cassell was a boy of six, he saw a movie that would set the course of his life. Jules Verne’s 20,000 Leagues Under the Sea. As Scott watched the Giant Squid attack the Nautilus somehow he knew his life would involve the ocean, submersibles and Giant Squid. In elementary school Scott read about the “Deepest Dive” of the US Navy’s Bathyscaphe ‘Trieste’. This amazing machine took two people diving 7 miles straight down the bottom of the ocean, the Challenger Deep of the Marianas Trench. His imagination went wild as he designed submersibles, learned to SCUBA dive and then became a commercial ‘hard-hat’ diver / welder at 15. When Scott was a young man he met someone that would soon become his best friend, adopted father and mentor in undersea exploration, Dr. Andreas Rechnitzer. Dr. Rechnitzer’s achievements are what the history books are made of. Andy was one of the very first divers in the US and developed a SCUBA dive-training program that was the basis for the modern day world wide recreational SCUBA certifying agencies. But it was after they became friends that Scott learned that it was Andy that developed and ran the historic program of the Bathyscaphe ‘Trieste’ and the ‘Deepest Dive’ into the Challenger Deep that Scott idolized as a kid! Andy encouraged Scott to enter the world of submersibles and soon thereafter Scott earned the prestigious title of U.S. Coast Guard rated submersible pilot / captain. It was through Andy that Scott met another historic figure, the man responsible for building America’s first deep submersible, the ‘Deep Jeep’, Will Forman. The Deep Jeep was piloted by then U.S. Navy Lieutenant Will Forman reaching the amazing depth of 2,000 feet deep and provided the US Navy with information that led the US in a new direction of powered submersible exploration. When they met, Will was working on a human powered submersible, the DaVinci II and Scott quickly volunteered to help. Scott found himself in Will’s back yard where this magnificent machine was engineered and built. As Scott helped lower the DaVinci II into the test pool right next to the garage, Will mentioned another project he always want to do but never did. It was called the Ocean Voyager and Andy was also interested in it. What was the Ocean Voyager’s mission? To explore entire oceans as a gigantic scientific transect in order to advance man’s understanding of the global oceanic environments. The Ocean Voyager concept vehicle was a 100 foot long submarine that was capable of reaching extreme depths down to 20,000 feet. It needed to do this for an incredible reason; it was to be an undersea glider! It was going to glide great distances just like a sailplane glider, just underwater. Designed as sleek as a shark it had three 9 foot interior diameter glass spheres that made up the pressure hull that would support the human crew of three, the life-support control station and the scientific data collection instrumentation. The remaining 70 feet of the glider was filled with a massive gas chamber and hydrazine pellets that when mixed with seawater create a (highly explosive) gas that would provide positive buoyancy bringing the glide slope upwards, then when the massive undersea glider was near the surface the gas would be vented just enough to allow slight negative buoyancy and the glider would descend along a glide slope. This energy efficient system would not only be new, but would provide silent propulsion allowing the science crew to ‘hear’ the sea life as never before. But, the project was cancelled before it ever began in the early seventies. In Summer 2003 Scott revisited the discussion about the Ocean Voyager concept with Andy. Andy reinforced the earth’s need for such a project considering the failing fisheries, the seas potential effect of climate, and many things that remain a mystery to man within the vast oceans. After a long heart-felt discussion, Scott made a promise that would set a new course of his life. He promised Andy that if he can design a method to perform the Ocean Voyager concept in the modern economy, we would do it. Since Andy’s passing on August 22nd 2005, Scott has made the Undersea Voyager Project his life’s mission. He promised his life’s mentor, and he promised mankind. With a stroke of luck, Scott read an article about the “X Prize” and man’s efforts to design and build a private sector reusable manned spaceship. The idea was that independent people could out perform the giant bureaucratic machine of government funded space programs by innovating smaller simpler systems. With this basic concept Scott had an epiphany. “Why go weeks underwater with a giant submersible that cost 100s of millions of tax payers dollars, when you can refit smaller, cheaper submersibles to do a better job at a fraction of the cost and use private fund sources?” This way the program can actually do more, include the world’s scientific community easier and can cross more than just the major oceans but the entire global undersea environments and be a global project rather than a military / national one. With this concept, the Undersea Voyager Project was born. Scott is a man of his word. To date he has methodically assembled an incredible team of space explorers, undersea explorers, scientists, philanthropists, and engineers. He has developed the UVP into non-profit status, acquired the proof of concept submersible, and has raised money to refit it to the new mission requirements. UVP has successfully and graciously received support from key organizations for sponsorship including Deep Sea Power and Light, OTS, Pentax, Blue Steel (Faber) and DeepSea FX. The Trilobite will launch in November 2008 for sea trials. The bottom line: The promise is happening… ---------------- What do you think about the Ocean Voyager’s concept, the and hydrazine pellet propulsion ? Would a gas producing chemical be a viable option for a emergency blow out? ... anybody a serious opinion on that? ---------------- Cheers, Wil concretesubmarine.com Last edited by wellmer : 12-08-2008 at 08:29 AM. |
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#118
12-06-2008, 05:44 PM
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regarding safety factors, i'm not sure there is a direct correlary to high rises and submarines. those of high rises range from 1.5 to 2 typically, but this involves judgement calls based on knowns, unknowns, and risk. further the failure of a high rise, for example, spells doom for the structure but not its occupants. consequently here, in this country, we provide duplication inherent to life safety issues. under a high rise scenario, occupants can still leave a building after it has been damaged beyond repair. that's going to be a very different scenario for a submarine i would imagine, where the options are either some sort of james-bond escape module, hot looking girl attached, or some sort of controlled failure mode that allows life safety. short story, you either make it so that occupants can escape upon failure, or failure is such that the submarine can surface and return safely to port in a damaged condition. with concrete, this necessary involves steel. somewhere, and the game is on to figure out just where. |
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#119
12-07-2008, 05:44 PM
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| Harleriverman If you are a 'concretexpert'  we might go somewhere here. Determine the stresses and then design the structure to resist them. The stresses are easy for this application and size but it's impossible to comment with any validity because there is no detail. The design also varies from the egg principle since it has holes in it. Concrete is more elastic than people realise with a much lower youngs modulus than steel. I asked before what the youngs modulus of the mix was, but no reply. It's highly probable that the steel will be the cause of the matrix micro cracking which will then propogate with each cycle, without a mechanism to prevent crack growth such as fibres in the matrix fatigue could be a real issue. I am particulallry concerned about areas such as the internal rigid bulkhead in connection with the hull. This is a concern for cyclic fatigue. But we cannot even estimate the strain without the steel schedule. What factor of safety? Given the indeterminacy of the predictions for internal stresses a high FOS would be a sensible design target. If operational load is 30 tonnes per square meter, add the FOS and analyze the strain, detail it in cross section and we'll have a good indication. This should be a starting point. After a basic design schedule the next step would be to see just how the cuttouts affect the structure and the cuttouts are another worry for me. Wilfreid doesn't appear to be approaching this as an engineered design but is basing it on observations of static structures and a "suck it and see" approach. Isotropic materials are so much more predictable and relaible long term. The operational depth of a Uboat was 300 ft with 19mm thick pressure hull that was simply a 3m pipe section with transverese frames. If you want an operational depth of 100 ft (30m) then scale it accordingly and it's very easy to work, coat it with epirez 3mm high build epoxy and it will be just as durable. Do you have any software for FEA reinforced concrete analysis ??
__________________ Mike Johns. |
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#120
12-07-2008, 06:26 PM
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| we use integrated engineering software (ies) to model. i'm with you on the strategy, and hoping to get some more information from someone that posted practical perspectives on shotcrete. lost the thread but was insightful in terms of the stresses that subs face, something i have to image. i'm with you on the egg principle too, and i'm starting with fc = 6,000 psi. this gets sketchy in terms of assumptions on the aggregate since the over all theme here seems to be eliminate steel. i'm not of fan of fiber, but clueless on what the marine world has developed over the years. and i'm more concerned really with the means / methods of construction than the absolute purest math of it all. fos seems a pressing question here, i'm really not there yet. in our approach to design of more radical structures we start with failure modes, then isolate special load conditions towards redundancy that is practical but on target with the risks. becomes an exhaustive, iterative process and right now i'm marching down the road of hybrid of wellmer's concept. fos will follow on a finite basis, with some systems perhaps in the conventional ranges of 1.5 to 2.0 but some systems may require higher fos depending on their load conditions and role in the structure. i'm so far from there right now i need to just do it on the math model side. 30 t / m2 is a start, and makes sense given my understanding of the service loads for this vessel. many, many apologies all but i'm not a ship designer. this is not what i do, but its a good exercise certainly. what do you mean by cuttouts? |
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