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Upper School Engineers Design Rubber Band Paddle Boats
Part physics, part 3D design, and part water trial, a recent project turned abstract engineering principles into splash-making reality.
Upper School Engineering teacher Brianna Ifft wants to ensure her students have the fundamentals of prototyping, iteration, and 3D design well-established at the beginning of the semester. To assess their abilities, she challenged students to build a boat powered solely by a wound-up rubber band that could travel at least 50 centimeters down a 10-foot rain gutter filled with three inches of water. All students began with the exact same standardized paddle wheel assembly, but the hull design was entirely theirs to devise.
Before touching a 3D printer, student engineers had to navigate a series of real-world design constraints, including:
- Strict slender specifications: Hulls could not exceed five inches in width to prevent jammed paddle wheels in the gutter walls.
- Low-water navigation: Designs had to be precise to ensure the paddle wheel reached the water without scraping the bottom in just three inches of water depth.
- Hands-on prototyping first: Before entering the digital realm, students constructed physical prototypes out of foam or cardboard to run preliminary water trials.
- Smart CAD techniques: In TinkerCAD, students had to intentionally incorporate at least five key 3D modeling features—including Align, Duplicate, Fillet, Chamfer, and a personalized name tag using Text or Scribble.
In true engineering fashion, the measurement of success isn’t only who crosses the finish line first, but also what students learn from every trial and tweak along the way.
Grading was primarily process-based, and a boat that sunk on its first run might still earn an A+ if the engineering log documented the reason it tipped and the adjustments to the next print that fixed the center of gravity.
Students were limited to two to three total prints, forcing them to use testing logs, PrusaSlicer data, and physical reflections to justify every change between versions. The iterative process required them to tackle big design questions like:
- Should the hull be a streamlined wedge or a stable flat-bottom barge?
- Where should the rubber band anchor to maximize torque without bending the frame?
- How do fillet edges reduce drag in fluid dynamics?
Parker is proud of the student engineers and their teacher for developing these new skills.
Click here for photos.
Francis W. Parker School educates students to think and act with empathy, courage and clarity as responsible citizens and leaders in a diverse democratic society and global community.