35 Rapp. P.-v. Réun. Cons. int. Explor. Mer, 168: 35-38. Janvier 1975. TONNAGE CERTIFICATE DATA AS FISHING POWER PARAMETERS F. d e B e e r Netherlands Institute for Fishery Investigations, IJmuiden, Netherlands INTRODUCTION London, June 1969 — An entirely new system of The international exchange of information about measuring the gross and net fishing vessels and the increasing scientific approach tonnage was set up called the to fisheries in general requires the use of a number of “International Convention on parameters of which there is a great variety especially Tonnage Measurement of in the field of main dimensions, coefficients, propulsion Ships, 1969” .1 data (horse power, propeller, etc.) and other partic­ ulars of fishing vessels. This variety is very often caused Every ship which has been measured and marked by different historical developments in different in accordance with the Convention concluded in Oslo, countries. 1947, is issued with a tonnage certificate called the The tonnage certificate is often used as an easy and “International Tonnage Certificate”. The tonnage of official source for parameters. However, though this a vessel consists of its gross tonnage and net tonnage. certificate is an official one and is based on Inter­ In this paper only the gross tonnage is discussed national Conventions its value for scientific purposes because net tonnage is not often used as a parameter. is questionable. The gross tonnage of a vessel, expressed in cubic meters and register tons (of 2-83 m3), is defined as the sum of all the enclosed spaces. INTERNATIONAL REGULATIONS ON TONNAGE These are: MEASUREMENT space below tonnage deck trunks International procedures for measuring the tonnage tweendeck space round houses of ships were laid down as follows : enclosed forecastle excess of hatchways bridge spaces spaces above the upper- Geneva, June 1939 - International regulations for break(s) deck included as part of tonnage measurement of ships poop the propelling machinery were issued through the League space. of Nations to obtain a kind of uniform “param eter” (gross However, the following are not included in the gross tonnage and net tonnage) to tonnage: use for harbour dues, dock dues, lock dues, canal dues, etc. double bottom spaces ceiling in holds Oslo, June 1947 - A convention was held to dis­ parts of tanks concrete floors in fish cuss differences in the regula­ space of engine room base holds tions for tonnage measurement casings space of fish processing of ships and in the application machinery of such regulations, the “Con­ vention for a Uniform System All the included spaces are measured from top of of Tonnage Measurement of frames, beams, floors, etc. (Fig. 16). Ships” . It is clear that gross tonnage must be regarded as a Oslo, May 1965 - A revision of the regulations of kind of “administrative parameter” . Great differences the 1947 convention. The ton­ can occur in the gross tonnages of vessels with similar nage mark was introduced. 1 As of September 1974 this was not yet in force. 3* 36 F. de Beer 3. type lb a tonnage certificate for vessels with more than one deck. For this type the second deck is the tonnage deck (open shelter deck ship). A tonnage mark is required. This system of measuring gross tonnage can create great differences between similar fishing vessels as the following example shows. Two Dutch trawlers built on the same design (body plan, construction plan, etc.) and having the same dimensions given below Figure 16. Tonnage measurement according to 1947 (1965) con­ vention. length overall 50-16 length p.p. 43-25 moulded breadth 8-50 depth upper deck 6-45 depth second deck 4-20 mean draught ± 4.00 have the following tonnage certificates: vessel SCH 171 SCH 6 type of vessel stern trawler stern trawler year built 1966 1967 identification length 46-35 m 46-30 m type o f certificate I lb Figure 17. Tonnage measurement according to 1969 convention. tonnage deck upper deck second deck gross tonnage 605-81 register tons 362-27 register tons dimensions, displacement, etc. due, for instance, to The main dimensions of a vessel given in the tonnage the positioning of watertight bulkheads in super­ certificate, called identification dimensions, are only structures, differences in type of construction, applica­ set up for the determination of the tonnage. They are tion of excluded spaces, and type of tonnage certifi­ (a) overall length: the distance between the extreme cate. end of the stem and stern. Differences in gross tonnage of 10% to 15% can (b) length : from the fore side of the upper­ occur between similar fishing vessels, measured in ac­ most end of the stem to the aft cordance with the regulations of the convention of side of the upper end of the stern- 1947 but before the revision of 1965. post or, if there is no sternpost, to The upper deck (weather deck) of fishing vessels the point of intersection of the fore with more than one deck was generally regarded as side of the rudderstock and the the tonnage deck. upper deck. The 1965 convention which came into force in the (c) breadth : extreme outside (rubbing pieces Netherlands in April 1967 introduced the tonnage not included). mark. This resulted in three types of tonnage certifi­ (d) depth : the depth is measured in the cates, viz. : middle plane at half length, from the underside of the upper deck 1. type I a tonnage certificate for vessels with one to the upperside of the double deck (upper deck = tonnage deck) ; no bottom plating or top of floors. tonnage mark required. 2. type la a tonnage certificate for vessels with more than one deck and having two gross ton­ THE 1969 LONDON CONVENTION nages. Recognizing that the establishment of a universal upper deck = tonnage deck (closed shelter system of tonnage measurement for ships should con­ deck ship) stitute an important contribution to maritime trans­ second deck = tonnage deck (open shelter port, a conference was held (London, May/June 1969), deck ship) upon the invitation of IMCO, for the purpose of draw­ A tonnage mark is required. ing up a new international convention on tonnage Tonnage certificate data as fishing power parameters 37 Table 15. Stern trawlers Tonnage Certificate data Bodyplan data Gross tonnage Length Year Registration no. 1947 1947/1965 o.a. B D built H.P. L s B s D s L pp Lew I m m m m m m m m type I type lb U K 66 1968 540 104-53 26-08 24-92 6-62 2-59 24-50 6-60 3-10 GO 14 1968 705 120-32 26-25 25-09 6-62 2-77 ---- 24-50 6-60 3-30 KW 141 1966 1200 528-36 48-25 44-92 8-54 3-62 42-00 ---- 8-50 6-45/4-25 SCH 44 1965 500 64-82 25-65 24-06 5-63 2-16 ---- 22-20 5-60 2-60 \ OD 10 1963 720 76-87 25-65 24-71 5-63 2-12 ---- 22-20 5-60 2-60 / senes KW 15 1961 1200 477-56 348-09* 45-62 42-50 8-52 3-79 41-25 ---- 8-50 4-32 KW 41 1963 1200 484-00 345-41* 45-92 42-78 8-52 3-79 41-25 ---- 8-50 4-32 KW 43 1962 1200 480-17 347-72* 45-65 42-53 8-52 3-79 41-25 ---- 8-50 4-32 1 serles KW 123 1964 1200 482-55 335-60* 46-00 42-87 8-52 3-79 41-25 ---- 8-50 4-32 KW 170 1967 1200 375-46 49-15 46-02 8-52 3-48 45-25 ---- 8-50 4-32 \ 4 3 2 i series IJM 57 1966 1320 559-57 49-12 46-06 8-52 3-48 45-25 ---- 8-50 U K 205 1967 660 101-27 26-20 24-07 6-72 2-75 22-85 ---- 6-70 3-40 U K 207 1967 660 101-27 26-20 24-07 6-72 2-75 22-85 ---- 6-70 3-40 > series OD 5 1968 705 104-80 26-20 24-52 6-72 2-75 22-85 ---- 6-70 3-40 KW 81 1967 1600 382-44 49-99 46-13 9-02 5-62 43-50 ---- 900 6-55/4-34 SCH 24/SCH 33 1966 1240 643-74 390-80* 49-84 46-27 8-52 5-30 43-00 ---- 8-50 6-54/4-34 SCH 123 1968 1240 377-00 51-91 48-05 9-02 5-46 45-50 ---- 9-00 6-39/4-24 SCH 110 1967 1200 362-26 49-75 46-18 8-52 5-40 43-00 ---- 8-50 6-39/4-24 G O 9 1967 680 120-19 26-19 25-09 6-03 2-95 ---- 24-70 6-00 3-40 SCH 34 1966 700 91-80 29-50 28-17 5-93 2-48 26-50 ---- 5-90 2-90 U K 64 1967 500 133-01 28-60 26-85 6-42 2-52 25-10 ---- 6-40 3-40 U K 89 1967 450 78-20 26-00 24-54 5-92 2-16 22-60 ---- 5-90 2-90 \ 2 go i series U K 121 1965 435 76-20 25-46 24-14 5-93 2-22 22-60 ---- 5-90 remeasured: vessels with a new tonnage certificate. measurement of ships. It was decided that the con­ tonnage (present) is 98-10 register tons. The total vention should come into force 24 months after the volume of all enclosed spaces V = 329 m3 and hence date on which not less than 25 governments or states, K, = 0-2503.