3D Printing a Scaled Catamaran: Composite Materials in Marine Structures
How custom composite filaments and FFF printing were used to produce a scaled catamaran hull — combining structural carbon fibre reinforcement with water-resistant polymer matrices.
The Project Brief
Scaled marine vessel models serve multiple purposes in research and development: hydrodynamic testing, structural concept validation, and as demonstrators for novel material applications. A scaled catamaran hull offers specific design challenges — thin hull sections that must be stiff enough to resist hydrostatic loading, structural continuity between the twin hulls, and material performance that remains stable after extended water exposure.
Material Selection
PETG was selected as the hull matrix for its combination of water resistance, chemical resistance, and processability. Short carbon fibre at 15% loading by weight provided a worthwhile stiffness increase without excessive brittleness. The cross-beam material — CF-nylon — was selected for its higher stiffness-to-weight ratio and excellent fatigue characteristics important for structural connections.
Extrusion and Printing Process
Both filament formulations were produced in-house using Noztek equipment. The CF-PETG was processed at 250–260°C with careful attention to fibre loading uniformity — tested by cross-sectioning samples and examining under microscopy. Diameter consistency was verified with laser measurement equipment before printing commenced.
Performance Results
The completed model was tested in a controlled tank environment over a series of loading conditions. Hull stiffness met the structural targets established at the outset. Water tightness was achieved through material selection and post-print surface treatment. The project demonstrated that FFF printing with custom composite filaments can produce functional marine structural components at model scale.