This is a model for a toy submarine. I printed this for my nine month old baby to play with during bath time. "under supervision" The model features a spinning seven blade prop. Also a detailed hatch, periscope and handle. The toy fills with water and sinks. I have added holes for 2-3 pennies to be added in case its too top heavy.
Print the bottom and middle as is with a 20% infill and support. The prop should be printed with 100% infill with support everywhere. The upper with 25% or more infill and support with a 10 line brim. This should yield a strong toy overall.
You should be able to scale it up slightly if you want a bigger toy. First one to print a yellow version wins.
Finishing the toy
You may need to carefully use a X-Acto knife to free the prop from the axle. Take care when removing the support material from the top section of the prop so it will fit on the bottom and middle sections. Sand most parts then use super glue to affix the sections together. Be careful not to glue the prop onto the axle.