c
10.6 8.3
2) Capacity of the world fleet (in million tdw)
g) Total deadweight 30.8 22.5
h) Corresponding cargo deadweight (0.96 X g) 27.9 21.4
3) Annual carrying capacity (in million tons)
i) Theoretical (h x f ) 296 178
j) Actual (0.90 x i) 266 160
This table, however, stresses the fact that the tramp fleet has a much lower efficiency than bulk carriers (— 22% ). This is explained by their lower opera tional speed and, above all, by the time spent in harbours, almost twice that of bulk carriers.
This is of course related to the fact that bulk-carriers proper take the best trade and, leave the less regular business, the smaller shipments and the most difficult harbours to the tramps.
In the future, it seems inevitable that tramps will be eliminated by the big single deck ships from substantial and long distance bulk trade; consequently they will be used more and more on the most difficult routes.
It has thus been assumed that, up to 1975, the average length of haul covered by tramps would tend to shorten but that, despite this diminution, the average effi ciency of the fleet would not change as compared with 1966. This led to the prediction that the present rate of efficiency, i.e. 8.3 loaded trips per year, would be maintained. On the other hand, for the period 1975-80, the current moderniza tion of this sector of the world fleet suggests an increase in the rate, which may reach 9.7 by 1980.
By evaluating these estimates and the share of bulk cargoes shipped in 1975 and 1980 which will not be absorbed by specialized single-deck ships, table X X III makes it possible to estimate the total deadweight of the tramp fleet that will still be in service at the end of both periods considered.
Therefore, the tramp fleet should already be reduced to a deadweight of between 14 and 17.3m. tons by 1975. The diminution of the fleet will continue from 1975 to 1980, and, for this last year, a fleet of between 8.8m. and 11.7m. tdw can be foreseen.
TABLE XXIII
Forecasts on total deadweight tonnage o f tramps in 1 9 7 5 and 1 9 8 0
Growth estimates 1975 1980
Low High Low High
I. 6 main commodity trade carried by tramps
(1000 m. ton/miles) 280 350 191 256
II. Average cargo-carrying distance 3 200 3 000
III. Quantities shipped (million tons) /T\ (1)
a) Main commodities 88 109 64 85
. (I3C)
b) Other bulk commodities 22 28 17 23
c) All bulk commodities 110 137 81 108
IV. Efficiency rate 8.3 9.7
V. Corresponding fleet (in million tons) a) Cargo dw
(IV)\ / 13.3 16.5 8.4 11.1
b) Deadweight tonnage
4. Expected deadweight of the cargo-liner fleet, including container ships, in 1975 and 1980
a) E f f e c t s o f c o n t a i n e r i s a t i o n o n s e a - b o r n e g e n e r a l c a r g o t r a n s p o r t
The forecasts of the future tonnage of this section of the sectorial analysis cor respond to the assessments made in Chapter II (B-3) about the development of the volume of sea-borne general cargoes up to 1975 and 1980.
Until recently, the fleet of cargo liners of more than 4 000 grt corresponded almost exactly to this section of maritime transport, which was defined in the preceding chapter according to the types of ship which carry it.
Today, the progress of containerisation and the appearance of a new type of ship which specializes in this transport, make it necessary for this prospective study, to divide the fleet into two sections and to establish which trade will be given to container ships out of what is left to conventional cargo liners. In fact, the expected efficiency of container ships is much superior to the one estimated for cargo liners.
b) F o r e c a s t s f o r t h e r a t e o f c o n t a i n e r i s a t i o n
For the reference year 1966, various studies suggest that, out of a general cargo volume previously estimated at 190 to 220m. tons, 50m. could have been con tainerized.
For the future, the forecasts for the expected growth rate of this theoretical volume as well as the percentage which will be effectively containerized, are summarized in Table XXIV, which also shows the volume of other general cargoes which will still be shipped on conventional cargo liners. This volume is derived from the forecasts previously made in Chapter II (B-3) about the overall general cargo trade in 1975 and 1980.
The minimum and maximum estimates for transport by conventional cargo liners correspond to the uncertainty over the exact volume of general cargoes carried in the reference year 1966.
c) E s t i m a t e d t r e n d o f t h e e f f i c i e n c y r a t i n g o f c a r g o - l i n e r s a n d c o n t a i n e r s h i p s
In order to calculate the deadweight tonnage of the world fleet of container ships and cargo liners in 1975 and 1980 required to meet the estimated transport needs in both categories of cargoes, it is first necessary to estimate the efficiency ratings to be expected for both types of ship. These estimates are shown in Table XXV.
i) Cargo liners position in 1968
It has not been possible to estimate the efficiency of container ships, in 1968, the way it has been done with cargo liners. Intercontinental container services were still at an experimental stage. On the other hand, the figures available for conven tional cargo liners have provided an estimated range of the efficiency of the world fleet operating at present.
This range depends, in fact, on the estimated time spent in port by ships of this category; this time is particularly long now because of the high number of stop-over calls made on most regular lines. The operating cargo-liner fleet has been estimated