Dimensions of piston tank

[Suppenmichel]

Hi, I am Michael. I want to build a submarine in 1:50 as a comlete beginner. Is hull is 3d printed and the wtc will be 100mm in diameter and maybe 800mm in lenght.
What dimensions should the piston tank have? I have no idea.. ist 700ml enough or should ich be way more? I am at very beginning and would like to gain some knowledge.

[He Who Shall Not Be Named]

Hi, I am Michael. I want to build a submarine in 1:50 as a comlete beginner. Is hull is 3d printed and the wtc will be 100mm in diameter and maybe 800mm in lenght.
What dimensions should the piston tank have? I have no idea.. ist 700ml enough or should ich be way more? I am at very beginning and would like to gain some knowledge.

We'll assume your plastic has a specific gravity near enough to water so as to not matter.

Determine the total volume of all structures above designed waterline that will be immersed... no air-pocket, IMMERSED. That's the floodable volume of your ballast tank, needed to transition from surfaced to submerged trim. As a practical matter, provide a ballast tank volume around 10% larger just for ****s and grins.

[Subculture]

If you're printing it yourself, one of the benefits of this is you can slice the file at the desired waterline in cad software (I like Fusion 360) then get the software to tell you volume in cubic centimeters of that part and that will directly give you the tank volume required in ml. You can add on a bit more as Dave said to account for paint etc.