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RCABS I'm over it

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  • RCABS I'm over it

    For the last few months I thought I try experimenting a little and resurrect my RCABS project.

    For those who don't know, I had a bad experience with RCABS a while back. It amounted to bummed out pump motor that gave temperamental power, which resulted in me wrongly condemning RCABS. I posted quite some time after, that with proper post examination, I had simply not done my homework.

    So I'd thought I'd give this system another go.

    I have to say that yes whilst it works, I am making a quick retreat away from the system.

    Why?
    First there is real estate. Using my almost complete Collins as a static test bed in my test tank, I have found that I need around 150% more air space to accommodate the bag inflation required to sit the boat at its surfaced scale water line.

    Second the bag positioning (even tethered) seems to inconsistently shift position effecting trim.

    Third, the additional air space required, alongside the basics of the WTC necessary gear and battery supply, prohibits additional nice features such as torpedoes

    Fourth, the additional air space required means that I need loads more ballast to trim the boat down and keep her stable. The cost of course, almost like a dry hulled submarine, is the boat is much heavier and less maneuverable than I would like.

    If you have a very large scale sub or a small sub that you're not to worried about additional features I am sure RCABS will work just fine.

    To me it occupies too much real estate on board and has the potential for trim inconsistencies.

    So I'll be back to gas and snort from here on in!
    Last edited by Kazzer; 02-10-2011, 06:13 PM.
    John Slater

    Sydney Australia

    You would not steal a wallet so don't steal people's livelihood.
    Think of that before your buy "cheap" pirated goods or download others work protected by copyright. Theft is theft.



    sigpic

  • #2
    Unlike so, so many threads dealing with the RCABS-gas ballast debate, John's words hold particular validity.

    John, and guys like him, write from experience. And their words are like gold to me; a very rare and meaningful thing -- something I can use to enhance my work. John identified the shortcomings of a system, stated them clearly, and his critique serves us all. His words are based on a comparative evaluation as to the utility of two different systems intended to perform the same function -- and from that experience he's identified the one that better performs the task at hand.

    Real, meaningful commentary.

    Too many of the RCABS threads have been launched from and/or contributed too by fools who have yet to either build a system or operate one. These slackers muddy the waters of knowledge and lead the newbies astray.

    And these same no-nothings have injected their ignorance into other areas as well.

    Too many people posting to forums offering detailed critiques about stuff they have yet to actually build or operate; these get-a-life, make-believe Craftsmen, artists, and engineers present themselves as qualified to discuss the merits of one system/mechanism/technique or methodology over another, and to offer 'advice' in fields they have no hands-on experience with.

    One short-coming of the Internet is the anonymity the Web gives these little people -- emboldening them to inject themselves into things they know little/nothing about.

    Hey! ... ***holes: Reading Wikipedia entries and watching episodes of How It Works does not make you an 'expert'. Shut the **** up till you actually KNOW something!

    Here's my take on the gas/LPB vs. RCABS debate: You can accomplish a task employing the minimal amount of mechanics and space. Or you can accomplish the same task with a Rube Goldberg machine, of dubious reliability, filling a room (look it up!).

    David,
    Last edited by He Who Shall Not Be Named; 11-24-2009, 06:44 AM.
    "... well, that takes care of Jorgenson's theory!"

    Comment


    • #3
      Well! Well! Well!

      Does this mean I should resurrect my old signature 'Having Gas Is Better Than a Leaky Bladder'. :wink: I guess I can, because I no longer have to pander to the 'politically correct police' (BTW does anyone go 'over there' any more?)

      David was quick to tell me yesterday that if I hadn't found the LPB pumps that would pump water, just as well as air, then we wouldn't have taken the huge step forward that the Snort system provided.

      There is only one system that will bring you back from the deep, and that is GAS, because it can still operate effectively at 100 feet, where as the RCABS pumps will be unable to counter the pressures encountered much beyond 30 feet. (depends on the pump of course)

      It was brought to my attention a while ago, that gas could escape from the ballast tank if the boat were tipped upside down, or it had nose dived. I wonder if that 'failsafe shot of gas' could in fact be injected into a bladder. If that were the case, then I guess there could be few arguments about the Snort system.

      Oh! Yes, Merriman! I spotted your 'cussin' again. Banned for 3 days - you bum!
      Stop messing about - just get a Sub-driver!

      Comment


      • #4
        bladder vs gas

        Bladder vs gas vs water pumps vs hybrid vs plain vs peanut, smoothy or crunchy, what ever you want - if it works for you then great.
        Having gas will clear a room and you will be called a pig but a leaky bladder, you can sit there and nobody knows till you stand up then you have had an accident.
        Is cussin' another way to say colourful adjective?
        Tor

        Comment


        • #5
          While ( almost ) on the subject, the LPB/snort is a proven no-brainer for this no-brainer builder, so can anyone above suggest a LPB pump with more capacity than the larger one offered?
          If I was trying to blow say,a 100-ounce tank ?
          -Kerry

          Comment


          • #6
            Have a look at car air horn pumps. These move air at an incredible rate, at low pressure. Will empty a tank that size in well under 10 seconds.

            http://www.amazon.com/dp/B00029XHQ8/...SIN=B00029XHQ8

            Will give you the best blow job you've ever had.

            Andy

            'awaiting pink pants'
            DIVE IN! Go on, go on, go on, go on, GO ON! http://www.diveintomodelsubmarines.co.uk

            Comment


            • #7
              Originally posted by kazzer View Post
              ........

              There is only one system that will bring you back from the deep, and that is GAS, because it can still operate effectively at 100 feet, where as the RCABS pumps will be unable to counter the pressures encountered much beyond 30 feet. (depends on the pump of course)
              Actually Mike, I have had an Alfa down to 5 metres in a Olympic Diving pool and surfaced with a non vented tank and pump system (not RCABS). That said the ascent fully blowing the tank was like a scene out of Das boot - took close to 20 seconds (which seemed like forever) for the valve to release the water held under pressure in the tank against the outside water pressure. But your right Gas in this situation would have seen her come up with great aplomb.

              Now get on to that quote of mine Mike!


              New ideas...
              Whilst I won't be revisting RCABS and will be using Gas / Snort, I still have not given up on pumps. In fact Jim Russell here in Australia has some blue water trials this coming Saturday with a new pump system. Many hours of tank testing has proved great success so far.

              The system uses a toliet cystern float sphere as the ballast tank. These comercially made floats coming in diameters of 80mm, 100mm, and 120mm.

              The tank structure has been pressure tested by Jim, a geared reversible pump in conjunction with a check valve operates fill and release of the ballast tank. The tank fills to a maximum of 70% water with the air inside compressed into the last 30% of the tank.

              Unlike other non-vented tank pump setups I have used, as the tank is a sphere - there is no need for baffles as gravity determines the waters position within the tank at all angles and dangles.

              The use of a geared pump I have cautiously avoided previously as I have seen a geared pump stay on due to a RX glitch and the tank blew up, but in Jim's set up should the pump stay on, the part failure is not the tank, but the connection to it. The connection failure occurs in the wet area, and in failing emptys the ballast tank.

              If I can get Jim into the digital age I'll get him to post photos. A long way to go in proving the reliability of the system - but Jim is quite the engineer and pretty much the grandfather to the Hobby in Australia.
              John Slater

              Sydney Australia

              You would not steal a wallet so don't steal people's livelihood.
              Think of that before your buy "cheap" pirated goods or download others work protected by copyright. Theft is theft.



              sigpic

              Comment


              • #8
                Originally posted by kazzer View Post
                ....

                David was quick to tell me yesterday that if I hadn't found the LPB pumps that would pump water, just as well as air, then we wouldn't have taken the huge step forward that the Snort system provided.
                Agree 100%
                John Slater

                Sydney Australia

                You would not steal a wallet so don't steal people's livelihood.
                Think of that before your buy "cheap" pirated goods or download others work protected by copyright. Theft is theft.



                sigpic

                Comment


                • #9
                  Originally posted by Subculture View Post
                  Will give you the best blow job you've ever had.

                  Andy

                  'awaiting pink pants'

                  OK! The award is waiting. Just send me your best photo of 'the pose' (sub in one hand, radio in the other, shorts & long socks) I'll do the rest!
                  Stop messing about - just get a Sub-driver!

                  Comment


                  • #10
                    Originally posted by kazzer View Post

                    Does this mean I should resurrect my old signature 'Having Gas Is Better Than a Leaky Bladder'. :wink: I guess I can, because I no longer have to pander to the 'politically correct police' (BTW does anyone go 'over there' any more?)
                    By all means Yes.
                    John Slater

                    Sydney Australia

                    You would not steal a wallet so don't steal people's livelihood.
                    Think of that before your buy "cheap" pirated goods or download others work protected by copyright. Theft is theft.



                    sigpic

                    Comment


                    • #11
                      Subculture,
                      Would that car air horn pump handle water as well?

                      Comment


                      • #12
                        If it ingested a little bit of water, it wouldn't do it a great deal of harm, but I wouldn't use it to pump water.

                        These pumps are vane based. They tend to use paxolin/tufnol vanes, so essentially they're maintenance free.

                        I connected one of them up to a 4 litre bottle, and it emptied in about 6 seconds.

                        If you want to pump water look on ebay for faucet pumps by Whale and Reich. They are high volume centrifugal pumps that run off 12 volts DC.

                        Cheap too.
                        DIVE IN! Go on, go on, go on, go on, GO ON! http://www.diveintomodelsubmarines.co.uk

                        Comment


                        • #13
                          Has anyone tried to combine the gas system together with the NVT/P? The standard gas system for fixed ballasting ( full/empty for full surface to deck awash) and the NVT/P for variable depth control.
                          Make it simple, make strong, make it work!

                          Comment


                          • #14
                            What's with all the acronyms? Speak english man!
                            DIVE IN! Go on, go on, go on, go on, GO ON! http://www.diveintomodelsubmarines.co.uk

                            Comment


                            • #15
                              Originally posted by redboat219 View Post
                              Has anyone tried to combine the gas system together with the NVT/P? The standard gas system for fixed ballasting ( full/empty for full surface to deck awash) and the NVT/P for variable depth control.
                              Yeah! ... what Andy said.

                              If you mean putting a non-vented trim tank within an open tank, yes. Mike and I are all over this -- you won't believe the tiny little peristaltic pump he's found!

                              David,
                              "... well, that takes care of Jorgenson's theory!"

                              Comment

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