An idea for a vent valve

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  • Kazzer
    *********
    • Aug 2008
    • 2848

    An idea for a vent valve

    As more and more boats are being made for use in swimming pools, the use of gas for emergency use becomes less of a necessity. Even the Great Wiz told me this weekend that he runs all his boats these days using Snort and leaving his gas tanks empty.

    Which brings us to the age old argument of RCABS (Really Crummy Awful Bladder System) :biggrin:and alternatives.

    So lets look at Snort. One pump, one vent valve. No compartments under pressure or vacuum, no pipes or bladders to leak.
    Whereas RCABS has pipes and valves, with potential leak problems.
    The other part about Snort I really like is that you ballast the boat with a full ballast tank, it is at periscope depth. Want to go deeper, then you dive using planes and motor to go deeper. Stop engines, and you'll reach periscope depth. It just makes so much sense to His Eminence and myself.

    Snort is SO simple and foolproof, I wonder why anyone operating in a pool would want anything else. Particularly when one looks at the price. For Snort, we're talking about a $60 pump and controller. The vent valve is operated by a cheap micro servo. That's IT!

    With all this in mind, it means we can dispense with a gas tank and the valves/ arms installed to operate it, but that leave the vent valve as a problem.

    I've often felt that valve could be incorporated into the aft ballast bulkhead, and yesterday I tinkered with the idea on paper.

    Click image for larger version

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    Click image for larger version

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    Here is my idea for modifying an aft ballast tank bulkhead to engage a Snort only vent valve.


    A 3/8" diam hole is drilled right through the bulkhead, And then approx half of it is drilled out again to say 1/2" diam

    A 3/8" x 1/8" Push-rod seal is glued into place.

    A custom made mount for the linear servo is screwed onto the dry-space side of the bulkhead to line up the 1/8" push-rod, which is threaded to take a knurled nut. On the bottom of the nut is glued on a half round rubber pad/seal. This is designed to sit onto the flange inside the hole when the valve is in the closed position.
    Finally a 1/8" diam hole is drilled on the wet side of the bulkhead, from the top down into the seal chamber, which allows the air to escape. A hole must be drilled through the Sub-driver casing.

    We need the following specially made

    An alumilite bracket mounting for the linear servo
    A rubber half round (dome shaped seal to go on the knurled nut.
    The push-rod with a threaded end to take the nut.

    I can get the linear servos made with extra long leads to enable the tray to be removed etc.

    OK! Tear it apart please guys!
    Stop messing about - just get a Sub-driver!
  • roedj
    Captain
    • Sep 2008
    • 562

    #2
    Originally posted by Kazzer

    So lets look at Snort. One pump, one vent valve. No compartments under pressure or vacuum, no pipes or bladders to leak.
    Mike,

    You have an interesting idea but for now I'm more interested in a claim you made for SNORT. I have installed a SNORT system in my SWM Blueback and I love it. Using one of Kevin's MPC's it's very easy to control.

    BUT...

    I installed the pump in the dry "engine room" of my WTC which means I have two "pipes" (the supplied rubber hose) running from the "engine room" out into the wet area. I have taken care to ensure that my pipes are attached tightly to prevent leaks. Are you saying that I should have or could have mounted the pump in the wet as well?

    Please see the attached pics ... Click image for larger version

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    Thanks for your time,

    Dan
    Born in Detroit - where the weak are killed and eaten.

    Comment

    • redboat219
      Admiral
      • Dec 2008
      • 2735

      #3
      Personally the current set-up of the vent valve standard SD looks sufficient enough.
      In your drawing you're just relocating the vent valve from the top of the wtc to the bulkhead.

      If you want to dispense with the valve I suggest you use a reversible pump to vent/blow air to and from the ballast tank. You could use that small peristaltic pump you showed a while back.
      Make it simple, make strong, make it work!

      Comment

      • Kazzer
        *********
        • Aug 2008
        • 2848

        #4
        Originally posted by redboat219
        Personally the current set-up of the vent valve standard SD looks sufficient enough.
        In your drawing you're just relocating the vent valve from the top of the wtc to the bulkhead.
        Yes and no. I eliminated the gas bottle and valve and made it operate with a linear servo. So all that makes it extremely simple. Most peristaltic pumps are large and clumsy at present and a small one to run smaller pool boats would cost about $100. I've only found one made in Japan.

        I'm not sure how you envisage setting that up either. The pump sucks air down the snorkel, then runs in reverse to pump it out? I don't understand how that would work. Perhaps you could expand? That would be a much greater drain on the battery, wouldn't it?
        Stop messing about - just get a Sub-driver!

        Comment

        • Kazzer
          *********
          • Aug 2008
          • 2848

          #5
          Originally posted by roedj
          Mike,

          Are you saying that I should have or could have mounted the pump in the wet as well?

          Dan
          I wasn't saying that. I guess if you did run the pump in the wet, you would still have the wires going out to the pump. So that boils down to wires or pipes and either one is a potential leaker.
          Stop messing about - just get a Sub-driver!

          Comment

          • Slats
            Vice Admiral
            • Aug 2008
            • 1776

            #6
            Mike,
            fine idea not filling the gas tankifyou're in enclosed safe waters. Fine also to lose the tank completely if again you have no plans to put the boat in "blue water" conditions.
            I for one DON"T want to see a change to the Gas /Snort combination or parts availability. There are still a large percentage of sub drivers in this game that have a SOE of "blue water ops". Gas in these conditions is a necessary fail safe.

            As far as the valve goes presently atop the tank presently, this is one area that I am keen to seen an improvement in. Its good as is, but I find it can be occasionally precious and sticky.
            The simplicity of what you have demonstrated for the valve is a good idea. You could easily gang a microswitch to the opposing sealed direction of the vent to activate the snort pump. The location of the aft ballast tank bulkhead IMO is the ideal location. In my view the the vent / snort functions should occupy a single channel on their own, with Gas on a completely separate channel (should you want it as a fail safe or active control). Presently of course we have GAS activation and vent activation on the same channel.

            When I get my next shipment from David I will be exploring a bit of a variation on what you have here Mike.

            Good thinking Mike, but please do not dump GAS components from your range. It has its place, which along with Vent/ snorts and water moving pumps, are proven far more superior than RCABS - Reguritating Crap About Ballast Systems

            Best

            John
            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.



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            • Kazzer
              *********
              • Aug 2008
              • 2848

              #7
              John

              We have no intent to dispose of gas. (Unless it is bean induced of course) My point is that some boats, especially the smaller ones don't operate well in 'Blue Water'. They bob around like corks, and can't be seen 50 feet from the dock. In my opinion, its ridiculous to even attempt to run these boats in these conditions. So where to run them? Pools, paddling ponds, reflecting pools and places where access is easy and the area is shallow. If you can wade out and get the boat in the event of a sinking, why bother to have a failsafe system on board? It's a waste of time, money and personally, I can't be bothered with the gas - I'd rather swim for it.

              On the other hand, if you have a 6' long VII or a British S or T class, and maybe a Revell Gato, these boats suck in a pool. You can't turn them or get them up to speed. So these boats are likely to end up being sailed in a lake or large pond and the depth is going to create a problem if a sinking were to occur. Gas is by far the safest method of blowing the ballast tank in the event of an emergency, and I'd want it on board. Would I want to use it as my main method of blowing the tanks? No! I prefer the Snort - it's more fun too! We've relegated gas to a fail-safe system only, thanks to the miniature Snort pumps.

              I think this hobby is beginning to evolve into categorizing these boats more and the major consideration is where you are operating, which determines what you need as a ballast system. And yes I've said it before and I'll say it again. RCABS is Darnel's invention of the 1950's - good in its day, but a dinosaur now!
              Stop messing about - just get a Sub-driver!

              Comment

              • Slats
                Vice Admiral
                • Aug 2008
                • 1776

                #8
                All good Mike,
                were on the same page -agree with everything.

                "And on the 8th Day He Created Gas with Snort and it was good, very good"

                J
                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.



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                • Slats
                  Vice Admiral
                  • Aug 2008
                  • 1776

                  #9
                  As the valve atop the tank sometimes sticks I was wondering if the alternative below would afford more reliable operation.

                  On the left we have a basic layout for how the SD vent valve works.
                  The vent / blow arm with screw attached actuates upon the valve, which is and acts as hinged piece of flexible rubber type material. The valve dimple on the end of it opens and closes the vent hole contained in the vent housing.

                  On the right we have a modification I am keen to try.
                  Here there is no vent housing and no hinged rubber piece. Instead we have a piece of rubber, could be like a small washer or other piece of contoured rubber, attached to the screw head attached to vent / blow arm.




                  In terms of the rubber piece to connect to the screw, I was thinking of experimenting with a pull through grommet, like the one shown here at my local rubber supplier in Australia:

                  The long cylindrical piece I would use as a guide to run into the centre of the vent hole, with the flat base attached to the screw and the contoured edges jammed into the vent hole base from below.

                  David - no doubt, in coming up with the current system in the SD, you have thought of other ways of venting the tank. Are there any flaws in my thinking here re the modifications?

                  Thanks

                  John
                  Last edited by Slats; 09-23-2010, 10:50 PM. Reason: add link to grommet
                  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.



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                  • redboat219
                    Admiral
                    • Dec 2008
                    • 2735

                    #10
                    Wonder if you could use this mini poppet valve I found in a carburetor repair kit in Kazzer's? proposed setup.



                    Either imbedded within the bulkhead or in the wet threaded in through it. In the latter you'll need a servo actuated rod passing through a gland on the opposite bulkhead to depress the valve to vent.
                    Last edited by redboat219; 09-24-2010, 12:02 PM.
                    Make it simple, make strong, make it work!

                    Comment

                    • Subculture
                      Admiral
                      • Feb 2009
                      • 2119

                      #11
                      There's a really neat design for a combined vent and blow valve by a Belgian modeller in the excellent Traplet publication 'Submarines- models and their originals' which any model submariner serious about their hobby should have in their bookcase.

                      You will need a lathe to make it however.

                      Comment

                      • redboat219
                        Admiral
                        • Dec 2008
                        • 2735

                        #12
                        Any chance you can share the design with us here without breaking any copyright law.:biggrin:
                        Make it simple, make strong, make it work!

                        Comment

                        • Scott T
                          Commander
                          • May 2009
                          • 378

                          #13

                          Go check out the valve on the laundry detergent bottle.
                          It looks like it could be engineered as a low cost blow valve.

                          Scott

                          Comment

                          • Slats
                            Vice Admiral
                            • Aug 2008
                            • 1776

                            #14
                            Originally posted by Slats
                            As the valve atop the tank sometimes sticks I was wondering if the alternative below would afford more reliable operation.

                            On the left we have a basic layout for how the SD vent valve works.
                            The vent / blow arm with screw attached actuates upon the valve, which is and acts as hinged piece of flexible rubber type material. The valve dimple on the end of it opens and closes the vent hole contained in the vent housing.

                            On the right we have a modification I am keen to try.
                            Here there is no vent housing and no hinged rubber piece. Instead we have a piece of rubber, could be like a small washer or other piece of contoured rubber, attached to the screw head attached to vent / blow arm.




                            In terms of the rubber piece to connect to the screw, I was thinking of experimenting with a pull through grommet, like the one shown here at my local rubber supplier in Australia:

                            The long cylindrical piece I would use as a guide to run into the centre of the vent hole, with the flat base attached to the screw and the contoured edges jammed into the vent hole base from below.

                            David - no doubt, in coming up with the current system in the SD, you have thought of other ways of venting the tank. Are there any flaws in my thinking here re the modifications?

                            Thanks

                            John
                            Hi Guys,
                            I am talking about a MINOR modifiction to an EXISTING setup with the SD. (I should have made that clearer).
                            There are a gizzlion ways to successfully put a vent valve in a RC sub. I have had personally in my first efforts with GAS (not with a Merriman sub driver) about three different ways involving stainless springs and washers BUT these old proven routes don't lend themselves to a modification in the location of the present vent of the SD and with working in union with the EXISTING actuating mechanism. So thanks but what I am really looking at is putting something in the same place as the exhisting vent using the same actuating arm.

                            David, when you get a chance - you thoughts please.
                            Thanks

                            John
                            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.



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                            • redboat219
                              Admiral
                              • Dec 2008
                              • 2735

                              #15
                              Saw this interesting set-up over at Model Boat Mayhem site forum.
                              Make it simple, make strong, make it work!

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