This is a parametric shrouded propeller. Easy to change lots of things about it like thicknesses, number of fins, angle of fins, etc. Made in OpenSCAD. I would like to eventually change the fins to be more like airfoils or something, but the current design prints quite well without supports or raft right on a heated build platform. I'm going to be using it on a DIY R/C boat. Of course, I just found the OpenROV propeller... I'm also working on an improved propeller with elliptical fins that change angle depending on radius instead of just flat plates for fins. The improved propeller probably wouldn't print quite as well (without supports), though. The design does work in Customizer, but not with sliders.I printed it out on a Makerbot Replicator using Makerware 2.2.0.46 using "High" settings with neither supports nor raft, with 100% infill, 5 shells, 0.10 mm layer height, Extruder at 240C (for added strength), build plate at 120C, speed while extruding of 90mm/s and traveling of 150mm/s (acceleration is on, and I'm running version 7.0 firmware). Worked great, looks great.