Benchy Rising & Diving Toy Sub

If it's not going to float properly anyway, why not make it Dive!

The Benchy Rising & Diving Toy Sub is inspired by the rising and diving sub's that used to be in the back of comic books or in cereal boxes from the 1950s to the 1980s. It uses the reaction from the baking soda and the water to create a carbon dioxide bubble under the sub to create buoyancy. When the sub hits the top it will tip over letting the bubble out and sink to the bottom. 

Getting the proper buoyancy and stability with the bubble for the rise to work properly was a hassle. Getting it to sink was easy…

Edit 4/13 : When I uploaded this, I messed up the license, obviously you can remix this. License fixed.

Video (Skip to 45secs if you don't care to watch the instructions of how to use it and just want to see it work):

Printing:

The .3mf I've provided prints the sub at a 85% infill and the Benchy topper at 0% infill. I've printed this with a White Esun ePLA-lite filament. Each filament has a different density and weight to it, so if you aren't getting a good rise or a good fall, try adjusting your infill on the sub. I'd recommend 80 to 95, obviously more exotic heavier or lighter filaments will need greater adjustment. With an Ele-goo PLA+ sea green, I still got a rise and fall but it was slower then my eSun filament, so I adjusted it the infill to 80% and got a good result. I'll have more tweaking steps below.

I've used tree supports as I find them easier to get off. For the grate support just give it a little twist or push it back and forth and it should come out.

If printing from the .stl files (Be aware when you open an .STL in your slicer it will just choose default slicer settings, these are wrong for this print and will not print properly for the toy to work. If you have a Bambu, just use my .3mf for no hassle.):

Mini-Sub: In most cases print with an infill of 80 to 90%. I suggest 85% to start. This is so the sub will sink. If you print it at the standard 15% it's just going to float on it's side.
 

Benchy Topper: Print with 0% infill. This is to act as a lighter counter weight to the sub and allow it to rise. If you print it at 85% at most your sub is going to hop at the bottom or fall over. 

How to Use it:

Item's needed:

1. You will need some type of water container that can hold at least 6" (152mm) of water and at least 4" (100mm) circumference. A fish tank, tub, bucket, glass vase, etc.  
2. Water
3. You will need baking powder. It uses very little, as you can see in the video.

Usage:

1. Wet the sub first. This helps the baking powder not fall through the grate in the middle of the sub.
2. Loosly spoon the baking powder into the cavity of the sub, I'd suggest you fill it about half way. This will be messy so do it over a towel or the sink. Clean of the top of the sub with your finger or a towel before putting on the topper.
3. Securely place the topper onto the sub, you may have to wiggle it a little to get it on. If you lose a little baking powder in the process don't worry.
4. Put the Sub in the water and shake it so you know you are getting good contact between the water and the baking powdering. This is key as this is what's going to make the bubble to cause the sub to rise.
5. The sub may not rise immediately (Although as you can see in the video mine rises pretty quick), but it should rise within a minute, maybe two depending on your print density and the filament. As some time passes it general rises and falls quicker.

Tips:

1. If the sub is rising very fast and not falling/falling slow or if it's rising very slow/falling fast adjust the filament density. As mentioned before with the two different filaments I printed with I got different rise and fall rates.
2. If your sub is not rising all the way up or not falling all the way down, give it a little time and it should adjust. If that still doesn't help try adjusting the topper either by removing it and placing it again back on the top or switching the direction you place the toper on.  This helped me when testing different prints and filaments.
3. If your sub it not rising or moving at all make sure your baking soda isn't completely caked from water or too compacted in. Normally I flip it upside down and see if it's bubbling to check. If it isn't bubbling, try cleaning out the sub and putting the baking soda back in.

Thoughts:

By a hassle I meant I restarted the entire thing once from scratch and then printed like 20ish of them before I got it rise and dive and finally a bunch more to get to where I was happy with it.

Some times it takes the sub a few minutes to get it's rhythm, where it might half fall or take a while to rise off the bottom. if you let it go for for a few minutes eventually it will normally develop a proper rise and fall.

Don't let all my tips and filament infill density talk dissuade you from printing a sub. Every time I've test printed this model it does rise and dive, I just want to make sure you get the best results as quickly as possible.