TM.5/Circ.5 Interpretations of the provisions of the International Convention on Tonnage Measurement of ships, 1969

1 The Maritime Safety Committee, at its sixty-third session (16 to 25 May 1994), agreed to a consolidated set of interpretations of the provisions of the International Convention on Tonnage Measurement of Ships, 1969, as set out in the annex, which supersede interpretations contained to in circulars TM.5/Circ.1, TM.5/Circ.1/Corr.1 and TM.5/Circ.3.

2 Memher Governments are invited to use these interpretations when applying the provisions of the 1969 Tonnage Convention.

Annex Interpretations of the provisions of the International Convention on Tonnage Measurement of ships, 1969

01 Definitions (article 2(8))

1 When establishing the length of a rudderless flat top barge, the length should be calculated at 96% of the total length of a waterline at 85% of the least moulded depth measured from the top of the keel.

2 Column-stabilized units such as semi-submersible drilling units should be considered novel types of craft. Because the length under article 2(8) or the moulded breadth under regulation 2(3) for such units is misleading, it would be appropriate for such units to use the overall length and breadth to the outside plating between fixed structures. The citation of the length (article 2(8)) and breadth (regulation 2(3)) in the respective boxes of the International Tonnage Certificate (1969) should be deleted and a notation in the REMARKS column should be made to identify the ship as, inter alia, a "semi-submersible drilling unit", etc.

02 Application (article 3(2)(d))

The term "alterations or modifications which affect its tonnage" in resolution A.758(18) means increase or decrease of more than 1% in either existing gross tonnage or gross tonnage calculated in accordance with the 1969 Tonnage Convention.

03 Form of certificate (article 9(2))

1 The "Date" shown on the front of the International Tonnage Certificate (1969) refers to the year when the keel was laid or the ship was at a similar stage of construction (article 2(6)) or the ship underwent alterations or modifications as defined in article 3(2)(b) but when the year of construction or alteration or modification is 1982 or 1994, the month and day should also be described.

2 Information inserted in the "location" columns on the reverse of the International Tonnage Certificate (1969) should not be detailed.

3 The phrase "Date and place of original measurement" should refer to the Iissue of the original International Tonnage Certificate (1969) and should have no reference to measurement under pre-existing national systems.

4 The phrase "Date and place of last previous remeasurement" should refer to the date and place of issue of the last International Tonnage Certificate (1969).

04 Cancellation of certificate (article 10(2))

Ships holding an International Tonnage Certificate (1969), which do not comply with agreed interpretations of the provisions of the Convention, should be remeasured. The new characteristics should be determined and applied without delay.

05 Inspection (article 12)

A copy of the tonnage calculations may be provided together with the International Tonnage Certificate (1969) to the ship's master. Although not a requirement, nothing in the Convention would prevent Administrations from providing these calculations to ships flying their flag.

06 Definitions of terms used in the Annexes (regulation 2)

The following interpretations apply to the terms given in the paragraphs of regulation 2:

1 "Upper deck"

1.1 A discontinuity in the upper deck which extends over the full breadth of the ship and is in excess of 1m in length should be treated as a step as defined in regulation 2(1) (see figure 1 in appendix 1).

1.2 Steps situated outside the "length" (article 2(8)) should not be considered.

1.3 A discontinuity in the upper deck which does not extend to the side of the ship should be treated as a recess under the upper deck level (see figure 2 in appendix 1).

1.4 In a ship having openings in the side of the ship below the uppermost deck, which are not closed but limited inboard by weathertight bulkheads and decks, the deck below such openings should be considered the upper deck (see figure 3 in appendix 1).


2 "Watertight"
The Administration may decide on this term as a special definition for tonnage purposes is not needed.

3 "Amidships"
This term should be considered as the midpoint of the length as defined in article 2(8) where the forward terminal of that length coincides with the fore side of the stem.

4 "Enclosed spaces"

4.1 In regulation 2(4) there is no contradiction between the definition of enclosed spaces as being "bounded by the ship's hull, by fixed or portable partitions ..." and "... nor the absence of a partition or bulkhead, shall preclude a space from being included in the enclosed space".

4.2 Space located within the boundaries of "permanent or movable awnings" should be subject to treatment under regulation 2(5).

4.3 Tanks, permanently located on the upper deck, provided with removable pipe connections to the cargo system or the vent (de-airing) lines of the ship, should be included in V_c.

4.4 The volume of weathertight steel pontoon covers on hatchway coamings should be included in the calculations of the total volume (V) of the ship. If such covers are open on the underside, their volume should also be included in V_c.

4.5 Multipurpose ships which have the facility to trade with cargo hatches open or closed should always be measured with the hatch covers considered to be closed.

4.6 Masts, kingposts, cranes, crane and container support structures, which are completely inaccessible and above the upper deck, separated on all their sides from other enclosed spaces should not be included in the total volume of all enclosed spaces. Air trunks having a cross-sectional area not exceeding 1 m² may also be excluded under the before-mentioned conditions. All mobile cranes should be exempted.


5 "Excluded spaces"

5.1 The space between the side longitudinal bulkhead of a deckhouse and the bulwark below a deck extending from side to side supported by stanchions or vertical plates connected to the bulwarks, should be treated as an excluded space in accordance with regulation 2(5)(b) and (c) (see figure 4 in appendix 1).

5.2 In the case of a ro-ro ship, for exarnple, where the space at the end of an erection is fitted with means for securing cargo, the space should be included in V in accordance with the first condition of regulation 2(5).


6 "Passenger"
N₁ and N₂ should be obtained from the Adrninistration's maritime safety authority.

7 "Cargo spaces"

7.1 The volumes of the segregated ballast tanks should not be included in V_c provided they are not to be used for cargo.

7.2 The volumes of clean ballast tanks in oil tankers should be included in V_c when the ship is fitted with a crude oil washing system which would permit dual purpose cargo/clean ballast tank use of these tanks.

7.3 The volumes of dedicated clean ballast tanks should not be included in V_c provided that:

1. the tanks are not used for cargo;
2. the ship carries a single IOPP Certificate which indicates it is operating with dedicated clean ballast tanks in accordance with regulation 13A, Annex I, MARPOL 73/78;
3. the following notation is inserted in the REMARKS column on the International Tonnage Certificate (1969):
   "This ship carries an IOPP Certificate in conformity with regulation 13A, Annex I, MARPOL 73/78. The following tanks are dedicated solely to the carriage of clean ballast water: ..... "

7.4 The volumes of slop tanks for cargo residues should be included in V_c.

7.5 In fishing vessels, the volumes of fish processing spaces for fishmeal, liver oil and canning, tanks for re-cooling fish, wet fish bunkers, stores for salt, spices, oil and tare should be included in V_c. Fishing gear stores should not be included in V_c.

7.6 The volume of refrigerating machinery used for refrigerating cargoes and situated within the boundaries of the cargo spaces should be included in V_c.

7.7 The volumes of mail rooms, baggage compartments separate from passenger accommodation, and bonded stores for passengers should be included in V_c. The volume of provision rooms for crew or passengers and bonded stores for crew should not be included in V_c.

7.8 On combination carriers, where the owners request to have the dual purpose oil/ballast tanks converted to ballast tanks and excluded from V_c, the ballast tanks should be required to be permanently disconnected from the oil cargo system and not used for the carriage of cargo. The ship should then be remeasured in accordance with regulation 5(3). Any ballast tanks not to be included in V_c should be solely allocated to ballast, connected to an independent ballast system, and not used to carry cargo.

7.9 When determining the volumes of cargo spaces, no account should be taken of insulation, sparring or ceiling which is fitted within the boundaries of the space concerned. For ships which have permanent independent cargo tanks constructed within the ship, e.g. gas tankers, the volume to be included in V_c should be calculated to the structural boundary of such tanks, irrespective of insulation which may be fitted on the inside or outside of the tank boundary.

7.10 The volumes of dual purpose spaces such as those used for both ballast and cargo should be included in V_c.

7.11 Spaces allocated to passenger automobiles should be included in V_c.

07 Gross and net tonnages (regulation 3 and 4)

1 The K₁ and K₂ coefficients used in the gross and net tonnage calculations may be derived from either the table in appendix 2 of the Convention or from the formula in regulation 3 or 4 respectively at the discretion of the Administration.

2 The final tonnage figures determined in accordance with regulations 3 and 4 and stated in the tonnage certificate should be given in rounded down figures without decimals.

08 Calculations of volumes (regulation 6)

1 Bulbs, fairwaters, propeller shaft bossings or other structures should be treated as appendages.

2 Hawse pipes, sea-valve recesses, thruster tunnels, stern chutes in fishing vessels, dredging wells in dredgers and other similar spaces fitted in the ship's hull should be dealt with as spaces open to the sea.

3 Enclosed spaces above the upper deck, appendages and spaces open to the sea not exceeding 1 m3 should not be measured.

4 Volumes within the hulls of ships, such as split-hull barges and dredgers, should be retained in V and V c notwithstanding that the space within the hull is temporarily opened to the sea when discharging cargo (see figure 5 in appendix 1).

09 Measurement and calculation (regulation 7)

1 When a tonnage certificate and a copy of the calculations of the tonnages are transmitted to another Government in accordance with article 8(2) or 10(3) of the Convention, they should be accompanied by a form as shown in appendix 2, showing the ma in particulars of the tonnage calculations for easy reference. When listing underdeck volumes, the volumes may be combined (e.g. underdeck/extended forecastle, etc.) on the form.

2 Administrations should decide on the degree of accuracy required for the tonnage calculations.

10 Special types of ships

1 Livestock of ships

1.1 Livestock carriers are most often converted ships. Above the existing upper deck, one or more decks are constructed. Between these decks, the livestock corrals and their associated spaces are arranged, separated by, for example, railings, fences or gangways. The corrals are open to the air.

1.2 Stanchions, fences and railings to keep livestock in the corrals are "other means for securing cargo" according to regulation 2 ( 5) .

1.3 In applying the provisions of the 1969 Tonnage Convention, livestock structures should be included in the gross tonnage.

2 Dockships

2.1 A dockship may include in its main structural characteristics the absence of hatch covers above the cargo space but may have a dock deck above the moulded draught together with side erections (see figure 6 in appendix 1).

2.2 The dockships considered are described as:

.1 a dockship open-ended at the stern (see figure 7 in appendix 1); .2 a dockship fitted with a stern door or a grill stern door (see figure 8 in appendix 1).
2.3 The space above the dock deck, bounded on at least three sides by erections and intended for the carriage of cargo should be included.

2.4 In this context, an erection is defined as being an enclosed space bounded by bulkheads and a deck above.

 

Appendix 1

Figure 1
 
 

Figure 2

Figure 3

 

 

 Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Appendix 2 Form giving particulars of uniform tonnage calculation

• Informatietype: Internationaal
• Documentsoort: Circulaire niet in wetten.nl
• Toegangsrechten: Intern
• Identificatie: PUC_2356_14
• Versie: 2
• Datum beschikbaarheid: 12-09-2022
• Geldigheid van: 08-12-2006
• Wijzigingsdatum: 12-09-2022
• Titel: TM.5/Circ.5 Interpretations of the provisions of the International Convention on Tonnage Measurement of ships, 1969
• Organisatie: International Maritime Organization (IMO)
• Taal: Nederlands
• Onderwerp: Registratie / Registration
• Hoofdtaak: Koopvaardij / Merchant Shipping
• Thema: Zeevaart / Seagoing ships / Instructions to ROs / IMO Instruments (Instructions) / Circulars (Instructions) / TM Circulars (Instructions)