Net tonnage

Net tonnage

Net tonnage refers to the volume of a vessel's cargo spaces that can generate revenue and is determined by measuring the cubic contents of these spaces as prescribed by government regulations. It is one of the ways to calculate a ship's volume, with the other being gross tonnage which measures the total volume of the vessel.From: Offshore Petroleum Drilling and Production [2018], Dictionary of Oil, Gas, and Petrochemical Processing [2019], The impact of ship size on ports’ nautical costs [2020]

Stability and Trim—Tonnage, Safety of Life at Sea, Maritime Organizations, and Sea Change

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Published in George A. Maul, The Oceanographer's Companion, 2017

George A. Maul

Two other tonnages are in common use: gross tonnage—space available to earn income, and net tonnage—gross tonnage minus spaces not available to carry cargo such as machinery spaces and living space. Gross tonnage is arbitrarily chosen to be the volume in cubic feet divided by 100. For boats, the following are the formulae where L = length, b = beam, and D = depth:

The impact of ship size on ports’ nautical costs

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Published in Maritime Policy & Management, 2020

Gaston S. Tchang

For cargo ships, volume is, in literature, mostly used as a measure of a ship’s size (Cullinane and Khanna 1999). There are several ways to calculate a ship’s volume, the most common measures are gross tonnage (total volume) and net tonnage (volume of cargo spaces). Deadweight tonnage (dwt) is also a frequently used measure of a ships’ volume, dwt when measuring how much weight a ship can safely carry (McNicholas 2011, 30). As we can see in Figure 1 ship sizes, greatly increased in the last few decades. The average volume of a ship of the world merchant fleet increased by 77 percent in the period of 1995–2016 It seems that the end of this growth is not yet foreseen, when looking at the orderbooks and the new orders (see ISL 2016). We can see an increase of over 7 percent to an average deadweight of 75,698 tonnes of the ships on order in the period of January 2014—July 2016.

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Stability and Trim—Tonnage, Safety of Life at Sea, Maritime Organizations, and Sea Change

The impact of ship size on ports’ nautical costs