Small diameter WTC ballast tank on the outside?

[Scott T]

This picture shows the ballast tank internal on your smallest WTC.


Maybe it could be placed outside the WTC by doing something like the attached sketch.

[redboat219]

Questions:
1. Will the volume of your annular space the same as
your original ballast tank?
2. Will your wtc with it's enlarged ballast tank fit inside
your hull?

[Scott T]

You could make it as long as you need to increase or decrease the volume and still keep it in the same
diameter you require.
Will it fit who knows without experimenting.

Could maybe add a float to adjust decks awash see idea in attached sketch.

[He Who Shall Not Be Named]

Scott: One hell of a good idea. I see nothing but pluses to the design: it puts the fattest part of the boat hull around the ballast tank (Romel's question answered); eliminates external vent linkage; is adjustable as to longitudinal location of the tanks c.b.; and volume is also made variable (tank length) without interfering with the SD internals.

Damn, Scott, you should patent this arrangement. I will investigate this ballast tank arrangement after I get some long delayed things out of the way. Well done, sir!

M

[RCSubGuy]

I likey, a lot! Someone check my math (I'm darned tired right now)

With a small, 4" tank in stock form in a 2" cylinder, you'd be at about 9.6 cubic inches of volume. (assuming a 1.75" ID)
Each inch of sleeved tank would offer a net 5.2 cubic inches of ballast. (Each inch of 2" cylinder would reduce the 3.5" sleeve by 3.14 cubic inches and each inch of 3.5 OD (3.25" ID) ballast tank would offer 8.3 cubic inches)

So, to get the same 9.6 cubic inches of ballast you'd only need about two inches of sleeved ballast, resulting in a cylinder that could, theoretically be shortened by the entire original 4" tank length.

If 3.5" is too big, you could try 3" OD (2.75" ID) ballast sleeves which would net you about 2.8 cubic inches per inch of tank. Overall tank length would be about 3.5"?

Now my brain is churning!

[He Who Shall Not Be Named]

Scott T has taken us all back to school. Good stuff.

M

[Scott T]

Thanks for the complements. Everyone is welcome to any of these ideas. Especially since they come from reading and viewing your ideas.

My first thoughts were to use this for the larger size WTC. Then I saw what Dave M was using on the small Type-A sub
and thought it would only add a small amount of diameter to the WTC in use. The magnet idea comes from watching Dave M use the magnets in his
WTC designs.

Since the ballast tank is not a pressurized vessel it could maybe be made from thin soda pop bottle plastic.
1. Put some o-rings around your WTC tube. Or lay a foam bead used for filling cracks when caulking. Or lay down a bead of silicon caulk.
2.Cut the top and bottom off a litter pop bottle and cut the side to make a square or rectangle piece of plastic if it was stretched flat
3. wrap the plastic around the WTC + orings and hold in place with rubber bands/velcro or some other
4. trim plastic to make vent holes or form slot at bottom/keel of ballast tank
5. move the o-ring standoff closer together or further apart to change the tank volume

No easy ideas on the magnet valve. The thought was to arrange the magnets so they repell each other, maybe giving more strength to hold the vent valve shut.

[Slats]

Genius Scott.

J

[redboat219]

Yes, a great idea.

Anyone want be the first to build a working proof of concept?

[alad61]

No easy ideas on the magnet valve. The thought was to arrange the magnets so they repell each other, maybe giving more strength to hold the vent valve shut.

Now thats out of the square thinking :biggrin:. Just a thought in the magnets. What about adding another that attracts on the same lineal plane. Set it up on a lineal servo so when pushing it moves the repelling magnet under the magnetic valve to push it closed and when the servo gets thrown the opposite way the attracting magnet opens the vent. I'm no engineer put the principle should work...

[trout]

Scott,
that is one brilliant mind you have Scott!
there is a lot to this. Simplified wtc. No conduit for wiring or internal bulkheads. Better efficiency of space in the wtc.
mind is reeling with possibilities.

[vital.spark]

Interesting as that's where the ballast tanks are, outside the pressure hull on 1:1 double hulled subs!

[ffr2608]

Love it. I also like the magnets. Could we actually have a WTC with no pushrod seals? All connections (pushrods, drive) have been done successfully before. Just not all in 1 model.


D

[Scott T]

Did a little experimenting and proved the foam and pvc pipe I used would seal and hold air/water.
Foam negated the ballast water in the ballast tank/sleeve. Pictures below.

1. WTC in hull cradles showing space around WTC


2. Foam baker beads placed around WTC


3. Cut length of pvc pipe. Markers put in cut to show gap in pipe.


4. Pipe placed over foam beads showing how it compressed the foam which formed a seal


5. View of ballast sleeve on its side.


6. End of ballast sleeve showing the 1/2" foam bead setting in cradles in hull


7. WTC sitting in tub of water. I believe this is with the air in the ballast tank.
With it filled with water it set maybe a 1/4" lower as I think the foam offset the added water weight.


8. Setting on counter with water about half filled. Maybe you can make out the water line inside.


9. The sleeve completly filled held almost one cup of water.
The sleeve compressed the foam so it did not have 1/2" space overall.

[He Who Shall Not Be Named]

This is very, very good work. Impressive.

M