FREE!ship (formerly Freeship) vs. Alternatives: Which Naval-Design Tool Fits You?

FREE!ship (formerly Freeship): Complete Beginner’s Guide

Date: February 9, 2026

What FREE!ship is

FREE!ship is a free, open-source hull design and hydrostatics tool for small craft and ship models. It provides 2D/3D hull modeling, hydrostatic calculations, offsets generation, and export options for lines plans and meshes. It’s suited for hobbyists, modelers, students, and small-boat designers.

Key features

• Surface modeling: Create and edit hull surfaces using control points and curves.
• Offsets and lines plans: Generate station, waterline, and buttock offsets for construction or documentation.
• Hydrostatics & stability: Compute displacement, center of buoyancy, waterplane area, metacentric heights, and basic stability parameters.
• Resistance estimates: Basic resistance calculations (semi-empirical) to compare hull forms.
• Fairing tools: Smooth hull lines for better flow and aesthetics.
• Import/export: Export meshes (OBJ/STL), DXF lines, and offsets; import common geometry formats.
• Lightweight & offline: Runs on modest hardware; many users run it on Windows via native builds or Wine.

Typical workflow (step-by-step)

1. Start a new project: Choose units (m/ft) and set baseline parameters (length, beam, draft).
2. Define station planes: Place station positions along the length—these form the cross-sections.
3. Edit hull sections: Use control points to shape the profile at each station; adjust keel, chines, and sheer.
4. Set waterlines and buttocks: Add horizontal and longitudinal planes to check fairness and symmetry.
5. Fair the hull: Use smoothing/fairing tools to remove bumps and ensure continuous curvature.
6. Compute hydrostatics: Run hydrostatic routines to get displacement, LCB, KB, KM, and GM values at chosen drafts.
7. Run resistance estimate: Use the built-in methods to get preliminary resistance and power estimates.
8. Export outputs: Save offsets, lines plans (DXF), or 3D meshes (STL/OBJ) for CAD/CAM or printing.

File formats & interoperability

• DXF for 2D lines and lofting.
• STL/OBJ for 3D printing or CFD mesh preparation.
• Native project files for saving control points and station data.
• Can be paired with CAD tools, slicing software, and more advanced CFD packages.

Tips for beginners

• Start simple: Model a symmetric hull with few stations to learn controls.
• Use reference drawings: Scan or import lines plans to trace and verify proportions.
• Work iteratively: Shape rough form first, then increase station count and refine.
• Check hydrostatics early: Ensure buoyancy and trim make sense before detailed fairing.
• Save versions: Keep incremental saves to revert if a change breaks fairness.

Limitations & what to expect

• User interface can feel dated and less polished than modern commercial tools.
• Not a full-featured CFD package — resistance estimates are preliminary; use CFD for detailed analysis.
• Documentation varies by version; community forums and tutorials are helpful.

Learning resources

• Official project website and download pages (check for latest builds).
• Community forums, model-boat groups, and YouTube tutorials showing step-by-step modeling.
• Example hull libraries included with some distributions — study them to learn common practices.

Quick start checklist

• Install the appropriate build for your OS (or use Wine on Linux/Mac).
• Open sample hull included with the software.
• Create a new project, set units, add 5–9 stations, shape the midship and bow, compute hydrostatics, export STL.

If you want, I can:

• provide a 7-step tutorial with exact menu actions (assume Windows), or
• create a checklist tailored to designing a 3D-printable RC boat hull. Which would you prefer?