Ship Tonnage Calculator




Gross Tonnage (GT) and Net Tonnage(NT) Calculator for Ships

What this Excel based app does
This excel app helps the user calculate the Gross Tonnage (GT) and Net Tonnage (NT) for a ship more than 24 m in length
The calculations are based on the International Convention on Tonnage Measurement of Ships, 1969
Lists out all the possible enclosed spaces for the vessel, so no eligible space is missed out. Any additional space can be input as miscellaneous

Directions for Use
All the cells which require input are in the Worksheet ‘Inputs’ and have blue background.
Please fill only input cells, i.e., ones with blue background. Leave the other cells untouched, as they are output cells
Fill in the inputs in the Worksheet ‘Calculation’. Please keep the GA and other relevant drawings of the vessel available for ready reference
For all items, the option of using a calculator is available. To exercise the option, just select the ‘Type of Geometry’ in column E
If a calculator is being used for an item, its calculated volume will automatically be input in the column F of the item. However, the user can overwrite it
Multiple types of enclosed spaces can be included in the calculations. If a particular space is not applicable, user can leave the field as blank
An explanation sheet ‘Enclosed and Excluded Spaces’ has been added to help user determine which spaces are enclosed (only enclosed spaces are to be included in tonnage calculation)
Spaces other than those listed by their name can be input as miscellaneous items
Once the inputs are provided, the calculations for GT and NT are carried out

Assumptions and Limitations
1. Applicable only for vessels of length > 24 m

1. Transport Canada Publication – Standard for the Tonnage Measurement of Vessels – TP 13430 E
2. IMO International Convention on Tonnage Measurement of Ships, 1969

Version History
V0.0 15-Oct-20 First Issue

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