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[Rodgearing]

Well that's Christmas done with thank goodness lets get on with some thing constructive.
My dive unit is coming on seems to have taken a life time but hey.
My dive unit is of the simpler variety.  I wanted use a free flood ballast tank but thought I'd try and use the valve approach so I need an in line valve that will let, when open, water to flow both ways its to be mounted outside the dive unit also an in line water pump again to be fitted outside the dive unit 12 volts any suggestion where I may purchase these items ..please
Fred

[Subculture]

Not quite clear what you're trying to do, can you post up a picture or two of your dive unit showing details of the ballast tank and how you wish to fill and empty it?
 

[Rodgearing]

The tank is made of 100mm grey soil pipe each end is sealed.
At first I was going to use conventional submarine practise of having a hole at the bottom of the tank (free flood) and a vent at the top (solenoid valve) that opens on command allowing the boat to dive. 
To surface the boat I was using an air pump to purge the tank of water.  This works to a degree.
I haven't gone away from that idea.
But thought I might also try an in line pump that could either pump water in or out depending on what you wanted the boat to do.  All simple stuff.  I have a couple of solenoid Vvs but they are a bit clunky and I'd have to water proof them.  I also cant seem to find an two why in line water Pp.
Fred

[Subculture]

Are you planning to compress the air inside the tank, or vent it?

[Rodgearing]

No  KISS  Keeping it simply simple.
Tank with FREE flood hole in the bottom of tank
Hole on top of tank with solenoid Vv.
Place tank in water open Vv tank sinks
Pump air into tank with solenoid shut tank rises
OR
Use Pp to fill and empty tank.
Fred

[Subculture]

You will find that generally those valves have to be scratchbuilt. The ones in commercial kits are custom made. Fairly straightforward design as they don't have to seal against much pressure.

[Rodgearing]

OK Thanks

[Mankster]

If you want to use a solenoid valve, you could keep the body in the watertight area and run tubing to it to let air in and out .

[Subculture]

That would work with a water pump but not an air pump system

[redboat219]

How about a waterpump with a sealed tank?

Here's a link to a Spanish site http://www.u-modelismo.com/foromodelismonaval/index.php?topic=1379.0 where the builder used a 12v windshield washer pump and a pinch valve ( which you could substitute with the solenoid valve.)

[Rodgearing]

Thanks all.
Would like to find a small two way pump (pump in and pump out).
Any one?  Any where?
Fred

[Subculture]

What's the volume of your tank, and what diving speed/time are you looking to achieve?

What system voltage are you running at?

[Rodgearing]

No idea
Not fussed
12 volts

[Subculture]

Halfords do a small geared pump that some speak well of. But dive times will be sloooow.

[Davy1]

Quite a lot of information and discussion over on these links. (Apologies if you have been there already.)

Various pump types discussed including a long term test of the popular (red) pumps:

http://www.theassociationofmodelsubmariners.com/t286-pumps-geared-variety?highlight=red+pumps

Various valve systems for subs:

http://www.theassociationofmodelsubmariners.com/t380-pinch-valves?highlight=pinch+valve

A general description of ballast tank systems on this website:

http://associationofmodelsubmariners.com/

A happy new (building) year!

David

[Rodgearing]

Thanks David
I'm experimenting at the moment with a air tank (I built out of down pipe!)and an air Pp compressor.  See if that works.  Love experimenting best part of the hobby.
I can honestly say that most of the dive unit when finished  will, except for some of the electronics,  be scratch built.  I'm even thinking of building a set (two) ESCs
Fred

[Davy1]

Hi Fred,

Yes, that's the way!

(That's why model subs are so fascinating - still plenty of scope for experimentation.)

David