1. What is Gross Tonnage?

Definition: Gross tonnage (GT) is a unitless index related to a vessel's overall internal volume calculated from the moulded volume of all enclosed spaces.

Purpose: It's used to determine things like manning regulations, safety rules, and registration fees rather than actual weight.

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 volume of all enclosed spaces (m³)

Explanation: The coefficient accounts for the fact that not all internal volume contributes equally to a vessel's earning capacity.

3. Importance of Gross Tonnage

Details: GT determines a ship's size for regulatory purposes, affecting safety requirements, manning levels, port fees, and registration costs.

4. Using the Calculator

Tips: Enter the coefficient (typically 0.2 for cargo ships, 0.3 for passenger vessels) and total enclosed volume in cubic meters.

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 (engine room, crew quarters, etc.).

Q2: Why is the coefficient between 0.2–0.3?
A: This range accounts for different vessel types - lower values for cargo ships, higher for passenger vessels with more revenue-generating spaces.

Q3: How do I find the total enclosed volume?
A: This comes from vessel design plans or by calculating the moulded volume of all enclosed spaces.

Q4: Is this the same as displacement tonnage?
A: No, displacement measures actual weight of water displaced, while GT measures volume capacity.

Q5: What's the legal significance of GT?
A: GT determines which international maritime regulations apply to the vessel.