The IOM Urubu Project has been a fun journey filled with learning experiences. I've experimented with various techniques, from 3D printing the entire boat in PLA+ or PETG to moulding fiberglass hulls and combining them with printed parts.
3D printing opens up fantastic possibilities; it's easy to design custom geometries and produce finished parts. My first 100% 3D-printed boat looked amazing, but it capsized on the floor and cracked into two pieces! I never quite reconciled with PLA+ or PETG for making the hulls. I know that many succeed well with the technique; I've had a lot of dialogue with Knut Glende, who makes fantastic boats 3D printed in PLA, and reinforced externally with a layer of fiberglass.
For exploring new hull designs, this is particularly effective, but I'm still unsure if it's optimal for creating a hull that lasts over time, is light, suitably rigid and flexible, withstands impacts, and most importantly, doesn't deform in the sun.
My strategy has been to make hulls in fiberglass, from a form that is 3D-printed, using vacuum moulding. If the hull is fiberglass, all other parts can still be printed with good results. It's obviously more time-consuming, but when you do it, it's just fun!
Vacuum moulding gives incredible results. I was fascinated by the instruction videos on https://www.easycomposites.co.uk/learning about vacuum moulding.
The hulls are lightweight, sturdy, and if you're meticulous with preparations, you get a hull that doesn't need coating; it can be painted directly. My last hull weighed 380 grams before painting. For comparison, the PLA hulls weighed just under 600 grams at 1mm thickness.
I want to share experiences about this. I've made many mistakes and improved the technique along the way. I still have a lot that I can do better, but I feel that the result is already a boat that can compete in regattas and perhaps match the best mass-produced boats like K2, Venti, V11, etc.
My journey started like many others, based on a finished design from https://3dprintedradioyachts.com/introducing-iom-sabre-series/. Then I bought the drawings and 3D model from Frank Russel, the Ellipsis, a great design that I both printed in 3D and moulded with fiberglass.
Then I taught myself to draw 3D models using Blender, and created my own design. I have achieved good results by printing the shape, but also by printing a plug from which to make a mould.
Ellipsis vs Urubu
Build a mould from a plug is probably more relevant if you want to make several casts, but it is more time-consuming.
If there is interest, I will post more entries about the various phases. For for now, I'll share some pictures of the main flow that works for me:
Printing the mould:
I use a Prusa MK4. printing with PLA+ and 10% innfill:
Coating the mould
Necessary if you want to do vacuum, the mould will not be vacuum proof unless you coat it with epoxy
The resin infusion
From 3D printed mould
From a mould made prom a 3D printed plug
Assembling the hull:
Printing and assembling inner parts
Painting
