Pool submarine that travels a long distance in a pool.  I designed it for my kids, who love playing with this.

Profile was calculated for optimal laminar flow characteristics for typical pool environment (20 C, 2 m/s launch speed)

Model is easy to print in 3 parts standing up. Assembly is trivial and can be snap fit together in seconds

Recommend to add a M6 fastener of your choice in the mid portion of the toy to ensure nose heavy orientation and proper launch characteristics

Update:

Based on feedback, I have created a modified edition made of two pieces only, they are threaded together for easy connection. I dont want to make a single piece as the sub needs weight to work properly

Update 2:

Watched my youngest struggle with the torpedo as he could not generate enough launch speed. So I modified the design to be easier for younger kids and more forgiving. Printed it in black as that is actually better than the shiny colors.