Heel Angle Calculator
The heel angle calculator determines the transverse inclination (heel) of a vessel caused by shifting a known weight off-center. Calculating this angle is essential for understanding initial stability, safe load distribution, and verifying the metacentric height (GM) of your boat.
Understanding Heel Angle & Stability
When weight is moved horizontally across the deck of a vessel, the boat's center of gravity shifts, causing the vessel to incline (heel) to one side until the center of buoyancy realigns beneath the new center of gravity.
The Math Behind the Calculation
This calculator uses the standard naval architecture formula for initial stability:
tan(θ) = (w × d) / (W × GM)
- w = Shifted weight
- d = Transverse distance the weight was moved
- W = Total displacement (weight) of the vessel
- GM = Transverse Metacentric Height
Limitations for Large Angles
Note on Accuracy: This mathematical relationship is highly accurate for initial stability (typically heel angles under 7 to 10 degrees). As a vessel heels past this initial range, the metacentric height (GM) is no longer constant due to the changing shape of the underwater hull volume. For extreme angles, specialized stability curves (GZ curves) must be used.