{"id":238003,"date":"2018-11-22T09:53:43","date_gmt":"2018-11-22T08:53:43","guid":{"rendered":"https:\/\/thesailmaster.si\/2018\/11\/22\/bruto-in-neto-tonaza-plovila\/"},"modified":"2025-01-20T10:05:54","modified_gmt":"2025-01-20T09:05:54","slug":"bruto-in-neto-tonaza-plovila","status":"publish","type":"post","link":"https:\/\/thesailmaster.si\/en\/2018\/11\/22\/bruto-in-neto-tonaza-plovila\/","title":{"rendered":"Gross and net tonnage of a vessel"},"content":{"rendered":"

Gross and net tonnage of a vessel are data about its volume. They are important for calculating various vessel fees, for the validity of licenses to operate vessels, maritime safety regulations, and in some other cases. It is especially important for boaters who have passed the Boat Leader exam in Slovenia, which allows them to operate a vessel – a yacht (a vessel longer than 12 m that can carry up to 12 passengers) flying the Croatian flag, with the restriction that the gross tonnage of the vessel does not exceed 30 GT (more in the article: Which boat licenses allow navigation in the Adriatic<\/a><\/strong>).<\/p>\n

Until 1982, the unit RT or register ton (gross register ton and net register ton) was used to measure gross or net tonnage. One register ton equals 100 cubic feet or 2.832 m\u00b3. After 1994, an international agreement standardized the tonnage measurement system. It is now measured in cubic meters, and the unit is not written or used. Gross or net tonnage is expressed as a number without a unit, for example: GT = 30, which means the vessel has a gross tonnage of 30, but the volume of the vessel is not equal to 30 m\u00b3 and must be calculated using a formula.<\/p>\n

Gross and net tonnage<\/strong><\/h4>\n

Tonnage (gross or net) refers to the volume of enclosed spaces on the vessel and has no connection with the vessel’s weight. Gross tonnage of a vessel represents the total volume of enclosed parts of the vessel. Net tonnage refers to the volume of all enclosed spaces intended for passengers or cargo transport. Gross tonnage is denoted by the symbols GT, G.T., gt, BT, while net tonnage is denoted by NT, N.T., nt. The net tonnage of a vessel should not be less than 30% of the gross tonnage.<\/p>\n

How to calculate tonnage<\/strong><\/h4>\n

The calculation of the gross tonnage of a vessel is defined by rule 3 of Annex 1 of the International Convention on Tonnage Measurement of Ships, adopted in 1969. It depends on two parameters, V \u2013 the volume of the vessel and K \u2013 a coefficient that depends on the volume of the vessel. The coefficient K varies depending on the size of the vessel. It is smaller for smaller vessels and larger for larger vessels. It is calculated using the formula: K = 0.2 + 0.02 x log10<\/sub>(V). Once K is known, the gross tonnage of the vessel is calculated using the formula GT = V x K or GT = V x (0.2 + 0.02 x log10<\/sub>(V)). As we can see from the formula, gross tonnage contains the unit m\u00b3 and the logarithm of the same unit. Therefore, the unit is not used, and the term gross tonnage is primarily retained due to its historical significance.<\/p>\n

Calculation of gross tonnage for vessels registered in Croatia<\/strong><\/h4>\n

The calculation of gross tonnage for vessels in Croatia follows the international convention but has its specifics due to the definition of vessels based on their length. If we focus on those used for regular private cruising, recreation, and entertainment, these are:<\/p>\n

    \n
  1. “Brodica”<\/strong> \u2013 vessels with a length of 2.5 m to 12 m or vessels with an engine power of more than 5 kW<\/li>\n
  2. “Yacht”<\/strong> \u2013 a vessel for sports and leisure longer than 12 m and capable of carrying up to 12 passengers<\/li>\n<\/ol>\n

    Calculation for “brodice” vessels up to 12.00 m in length<\/strong><\/h4>\n

    The gross tonnage of vessels up to 12 m in length is calculated using the formula GT = 0.225 * V. V represents the total volume of the vessel in m\u00b3, which is calculated using the formula V = 0.55 * L * B * D + \u03a3 l*b*h, where:<\/p>\n