1. What is a Boat Gross Tonnage Calculator?

Definition: This calculator estimates the gross tonnage (GT) of a boat based on its total enclosed volume and a coefficient.

Purpose: It helps boat builders, owners, and maritime professionals determine a vessel's size for registration, regulations, and fees.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( GT \) — Gross tonnage (unitless)
• \( K \) — Coefficient (typically 0.2–0.3)
• \( V \) — Total enclosed volume (cubic meters)

Explanation: The gross tonnage is calculated by multiplying the vessel's total enclosed volume by a coefficient that accounts for the vessel's type and structure.

3. Importance of Gross Tonnage Calculation

Details: Gross tonnage determines a vessel's size for registration, safety regulations, port fees, and manning requirements.

4. Using the Calculator

Tips: Enter the coefficient (default 0.25) between 0.2-0.3 and the total enclosed volume in cubic meters. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between gross and net tonnage?
A: Gross tonnage includes all enclosed spaces, while net tonnage subtracts non-cargo spaces (like engine rooms).

Q2: How do I determine the coefficient (K)?
A: The coefficient depends on vessel type - 0.3 for cargo ships, 0.25 for passenger vessels, 0.2 for fishing boats.

Q3: Where do I find the vessel's enclosed volume?
A: Measure all enclosed spaces below deck and in superstructures, or consult vessel blueprints.

Q4: Why is gross tonnage unitless?
A: It's a dimensionless number representing volume capacity, not actual weight.

Q5: How accurate is this calculation?
A: This provides an estimate. Official tonnage requires precise measurement by certified surveyors.