Model Boat Mayhem
The Shipyard ( Dry Dock ): Builds & Questions => Submarines => Topic started by: nautilus on October 27, 2018, 01:10:36 pm
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hi all
im after a 800ml/1000ml rubber bladder one tube version if possible
anybody know where I can get one or similar
in the uk?
many thx
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I was about to ask the same question.
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Hi
Try a child swimming arm bands.
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try a blood monitor cuff chemists sell the cuff seperately
Mark
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try a blood monitor cuff chemists sell the cuff seperately
Mark
hi mate thanks will try that
cheers
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Good call Mark! I will be visiting Daughter in hospital this afternoon...Hmmmmmmmmm
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Hi
I recall one of the members of the AMS made one from some tights wrapped around a milk bottle and liquid Latex.
Pull one of the tights leg over the bottle, then paint the latex onto the covered bottle, twist the leg and pull back over the bottle and paint more latex onto the bottle twist again, do this until you have a few more layers, leave until dry, after a few days drying cut the end off and remove the bottle now make an end cap, you now have a flexible contain that will always return back to it's originally shape.
Have fun trying
Fred
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Have you considered an intravenous saline bag? Your local NHS establishment may be able to help you out with that. I think they have 500 and 1000 cc bags. A windscreen washer pump works well with them.
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S.H.G. did them they may still have some,
Tel 01785 840308
Email info@shgmodels.com
Fred
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:-)) :-)) :-)) many thanks...
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Hi
Sorry if I have missed just why you need them.
Would you be using them as part of the ballast system as used in the old Darnell type system?
Fred
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Basically yes. Not got funds for piston tanks and all the other fancy stuff. I needed smelling salts after I looked at Engels website!
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Hi P.O nick
have sent you a P/M
Fred
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If you make a hard tank, you can create any volume you choose, and you don't have to worry about them splitting.
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What about something like this?
(https://i.ebayimg.com/images/g/E8YAAOSw4-hZt4-8/s-l1600.jpg)
https://www.ebay.co.uk/itm/Horobin-Drain-Air-Bag-Canvas-4-6-9in-Options-Inflatable-Pipe-Blocking-Bung/251992980321?hash=item3aabf3bb61:m:m4o76S7uXCblEab-ugc759A:rk:1:pf:0
https://www.ebay.co.uk/itm/Horobin-Drain-Air-Bag-Canvas-4-6-9in-Options-Inflatable-Pipe-Blocking-Bung-/251992980321?var=
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Bags can be a pain in the ar5e, you're really better off avoiding them if possible. Some boats are difficult to avoid using one without significant modification- the Thunder Tiger Neptune is one that springs to mind, but if you're building something up from scratch, do yourself a favour and make a hard tank.
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Drain bung looks good, thanks Martin.
How does a hard tank work> Is it a sort of free flooding tank that air is pumped in to for buoyancy, similar to the real thing?
I have a 1 meter length of 90.. acrylic tube, I was going to chop it in to 3 pieces, forward one for pump, bow planes radio etc. Middle one as a ballast tank with the air bag inside to control buoyancy and the rear one housing motors, battery rudder and rear plane servos. I intend 3D printing end caps and equipment trays in ABS.
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Pretty much. There are various ways of implementing a ballast system. You can pump air or pump water- each method has its own pros and cons. Some systems compress air inside the tank or inside the module at various different pressures, others vent to the atmosphere through a vent or snorkel mast, once again there are pros and cons to each.
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Hi All,
All systems have good and bad points (cost, complexity etc.) There is a good review (link below) which gives the + and - :
http://associationofmodelsubmariners.com/pages/Divingsystems.html
David
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Many of the descriptions refer to systems from twenty years ago, and things have moved on. Some of the descriptions are misleading e.g. vented tank systems need larger hydroplanes and can use more power? Apparently compressed air ballast systems have expensive parts, not these days with mass produced pumps available from about £1.50p.
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So, here is the ballast tank. I will probably go for a pumped water type system using a windscreen washer pump, solenoid operated valve.
(http://modelboatmayhemimages.co.uk/images/2018/11/03/20181103_121640-600x800.jpg) (http://modelboatmayhemimages.co.uk/image/JPZAe)
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So, here is the ballast tank. I will probably go for a pumped water type system using a windscreen washer pump, solenoid operated valve.
(http://modelboatmayhemimages.co.uk/images/2018/11/03/20181103_121640-600x800.jpg) (http://modelboatmayhemimages.co.uk/image/JPZAe)
What's the tank originally? It sounds like your going for a high pressure system so I needs to be robust enough to take the pressure. Are you bonding the end on? What baffles are you using? That's a big tank and without them the sloshing effect will be terrible.
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The tank is 90mm acrylic tube with a 3 mm wall thickness. End caps are 3D printed in ABS and will have neoprene gaskets and M3 tie rods holding it all together. Baffles will be made the same way as end caps.
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I seem to have posted 3 photos of the same thing. Could an admin please remove?
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I don`t think the OP is using the whole tube as a ballast tank Tom I read that he is going to cut it into 3 pieces so there will be slosh but will be easier to control with a couple of baffles.
Mark
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That is a 1/3 piece of the tube. Other two will house fore plane servo radio and pump and motors rudder servo aft plane servo.
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Use a Kavan pump. You have the room for one, and they’re good quality.
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Just had a phone call from petty officer nick the tube is going in a 7foot darnel boat I don't think a 30 cm ballast tank will be enough to submerge the beast but I could be wrong
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Darnell didn't do a O-class. Sure it isn't a OTW? They're the only company I know of that do a large O-class, unless someone else did a one-off. They do nice light laminates ideal for model subs.
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Might have been me hearing wrong Andrew getting on a bit now lol
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I think it is OTW designs O class at 74 inches as it is the only model O boat hull I can find on internet.
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Yes sounds like OTW. Nice hulls, much better than Darnell IMO.
I see you have posted on the Dive-in facebook page where I have given some advice, which you can follow or ignore as you see fit.
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Yes, many thanks. I am trying to resist the temptation to go and fire up my workshop but I will be up all night faffing about so I will try and leave it until tomorrow.