1. What is USCG Gross Tonnage?

Gross Tonnage (GT) is a measure of a ship's total internal volume calculated from the vessel's dimensions. The US Coast Guard uses this measurement for regulatory purposes, not the actual weight of the vessel.

2. How Does the Calculator Work?

The calculator uses the USCG Gross Tonnage formula:

Where:

• \( L_{ft} \) — Length of vessel in feet
• \( B_{ft} \) — Breadth (beam) of vessel in feet
• \( D_{ft} \) — Depth of vessel in feet

Explanation: The formula calculates the total enclosed volume of a vessel and converts it to gross tons, where 100 cubic feet = 1 gross ton.

3. Importance of Gross Tonnage Calculation

Details: Gross Tonnage is used for vessel registration, determining safety requirements, manning regulations, and calculating fees. It's a key measurement in maritime regulations.

4. Using the Calculator

Tips: Enter vessel dimensions in feet. All values must be positive numbers. The depth measurement should be from the top of the keel to the tonnage deck.

5. Frequently Asked Questions (FAQ)

Q1: Is gross tonnage the same as weight?
A: No, gross tonnage measures volume (100 cubic feet = 1 gross ton), not weight. Weight measurement would be displacement tonnage.

Q2: What's the difference between GT and NT?
A: Gross Tonnage (GT) measures total volume, while Net Tonnage (NT) measures volume available for cargo/passengers (GT minus spaces like engine room).

Q3: How accurate is this calculation?
A: This provides an estimate. Official tonnage measurements follow precise USCG rules and may include additional adjustments.

Q4: Does this apply to all vessels?
A: The formula works for most conventional vessels. Special rules apply to certain vessel types like open boats or multi-hull vessels.

Q5: Why is the multiplier 0.67?
A: The 0.67 factor accounts for the fact that not all enclosed spaces are usable volume (due to structural elements, curvature, etc.).