1. What is USCG Gross Tonnage?

Definition: Gross tonnage (GT) is a unitless measure of a ship's total internal volume calculated according to US Coast Guard (USCG) standards.

Purpose: It's used for regulatory purposes, determining manning requirements, 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 enclosed volume in cubic meters (m³)

Explanation: The coefficient accounts for the fact that not all enclosed space counts equally toward tonnage measurement.

3. Importance of Gross Tonnage Calculation

Details: Proper GT calculation is legally required for vessel documentation, safety regulations, and determining applicable maritime laws.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: What's the typical range for coefficient K?
A: Most vessels use 0.2–0.3. The exact value depends on vessel type and configuration as specified in USCG regulations.

Q2: How is this different from net tonnage?
A: Gross tonnage includes all enclosed spaces, while net tonnage subtracts non-cargo spaces like engine rooms.

Q3: Where do I find my vessel's total volume?
A: This comes from vessel plans or can be calculated by measuring all enclosed spaces in cubic meters.

Q4: Why is tonnage unitless?
A: It represents a measurement of volume (100 cubic feet = 1 ton) rather than actual weight.

Q5: How often should tonnage be recalculated?
A: Only when making structural modifications that change the vessel's enclosed volume.