A 3D-Printed Benchy Big Enough to Ride In

You know Benchy — or, more accurately, 3DBenchy. It is the little 3D tugboat model that everyone turns to when testing a new 3D printer. Daniel Norée at Creative Tools designed it back in 2015, specifically to act as a light torture test for 3D printers. Because it is so ubiquitous, people now use 3DBenchy models for standardized testing. For example, “speed Benchy” tests are common in certain acceleration-focused circles. It has also become something of a mascot for the 3D printing hobby, so Emily the Engineer paid homage to the icon by 3D-printing this Benchy that is big enough to ride in.

The Benchy model is popular for many reasons, including cuteness and recognizability. But it isn’t popular because it floats well. Its resemblance to a watercraft is almost entirely superficial and Norée designed it for 3D printer testing, not hydrodynamics. A standard Benchy won’t sink, because every thermoplastic material used for 3D printer filament is less dense than water. But it will immediately capsize. Simply scaling up the model wouldn’t make for a very stable vessel, which forced Emily to give Benchy a minor redesign.

Emily still wanted this to be instantly recognizable as a Benchy, so she didn’t go crazy. She simply made the keel much more prominent, instead of completely flat. That keel sits below the water line, so it isn’t even noticeable while on voyages. A few tests at small scales convinced Emily that the revised Benchy would be stable when made large enough for a person to sit in.

With the design work done, Emily divided the massive Benchy up into pieces small enough to print on Bambu Lab X1-Carbon 3D printers. She has six of those in her workshop, which helped to speed up the process. She then used 3D Gloop and plastic welding to assemble the pieces into the full-size boat.

The maiden voyage took place on Lake Hartwell, which is right next to Clemson University in South Carolina. In the shallow waters near shore, Emily discovered that her keel extension wasn’t enough to make the Benchy stable. It still had an obvious desire to capsize, which is considered very inappropriate among seafaring folks.

Redesigning and reprinting the entire boat would have been a lengthy and expensive chore, so Emily’s solution was to slap on some outrigger pontoons. When combined with an electric trolling motor receiving power from an onboard battery, the oversized Benchy was able to traverse the muddy waters with relative ease. It followed a route of about a mile (we aren’t sure if that is a nautical mile or a regular one) before the battery went flat, but that was enough to prove the Benchy seaworthy.