International convention on tonnage measurement of ships 1969:
International convention on tonnage measurement of ships were adopted by IMO on 23rd of June 1969 and was entered into force on 18th July 1982
Vessels built before 18th July 2018 were permitted to used old tonnage for 12 years after entry into force date or until 18th July 1982
The convention provide grounds for measurement of gross tonnage as a formula of moulded volume of all enclosed spaces on a ship and net tonnage as a formula of moulded volume of all cargo spaces on a ship.
Net tonnage should be taken as a minimum as 30% of the gross tonnage
International convention on tonnage measurement of ships introduced for the first time the “International tonnage certificate”
International tonnage certificate:
Application:
All vessels built after 18th July 1982
Surveys:
Vessels intended to be certified are subject to initial survey only, which means no annual surveys, intermediate nor renewals
International tonnage certificate issuance procedure
Procedure by RO:
Tonnage survey
Issuance of Interim International tonnage certificate valid for 5 moths
Survey reports to be completed and send along with supporting documents to RO HO for review
Upon satisfactory review, full term International tonnage certificate is issued without expiry date, which means it remains valid unless vessel has significant change which can affect it tonnage or vessel changes its flag then the new flag has to issue new tonnage
Procedure by flag:
In many cases the flag state issues the International tonnage certificate directly in this case previous full term tonnage is sent to the administration along with tonnage measurement calculations if it seems required by the flag state
Getting the International tonnage certificate issued by the flag state is much cheaper than getting issued by approved RO and shorter procedure is adopted where no need for the Interim certification