handling on board ship in order to limit the turn-round time. Such ships are under con- sideration, but because of their greater capacity, they would probably sail only between ports which serve whole continents; it is not expected therefore that they would visit Hong Kong and so provision of more than a 40-ft. depth of water at Kwai Chung is unlikely to be required.
Working Apron
6.10 Alongside each berth on the quay will be travelling cranes for loading and unloading containers from the ship. It is necessary to provide a working strip both for these cranes and for vehicles transporting containers to and from them.
6.11
6.12
6.13
The surfacing and structure of this apron must be strong enough to carry containers stacked 2-high anywhere on its area and to carry the wheel loads of the vehicles transport- ing the containers. Also, it is necessary to provide foundations and electric power for the cranes, and services for the containerships berthed alongside.
The loadings on the crane rails are governed by the lifting characteristics of the crane, by the wind loading on it and by the spacings of the rails and crane wheels. As noted previously, the Container Committee has now recommended that the lifting capacity of these cranes should be 50 tons.
It is important to ensure that the cranes should have sufficient outreach to cover the widest containerships likely to call at the berth. In 1966 these were expected to have a beam of 100 ft., but the 810-ft. ships for which provision is now being recommended, will have a beam of 105 ft. or more. The restriction of 106 ft. on the width of ships imposed by the Panama Canal is likely to be a limiting factor on ships calling at Kwai Chung, but it is considered that the crane foundations should be designed for an outreach of say 110 ft. in order to cater for wider ships in the future; this would be in line with the policy adopted for cranes in European ports. The crane foundations should also allow for loadings from winds of the order of 40 m.p.h. which is about the highest working wind speed and for loadings from typhoon winds where the crane is secured of the order of say 160 m.p.h. which is about the highest recorded speed of a gust in Hong Kong at low level.
6.14 Although diesel-powered container quay cranes are obtainable they cost more than the electric type and if two or more are required they are also more expensive to run. For electric cranes there are three principal methods of picking up the mains power:-
(a) From overhead conductors.
(b) From conductors in ducts below deck.
(c) By trailing cable.
Marshalling Area
6.15
6.16
The basic requirements of the container-marshalling area are that:-
(a) It should have sufficient capacity to hold the full number of containers to be loaded
on a containership and to receive those unloaded.
(b) It should be so sited and arranged as to minimise the time taken for transporting
containers to and from the quay cranes.
It should also have area available for storing empty containers which are temporarily at the Terminal and where possible, packed containers which are being held for a later ship.
The Container Committee in 1966 anticipated that for each of the largest ships one third of its load of 900 20-ft. containers would have to be handled, and that this would involve 300 inward and 300 outward movements. The area actually recommended then was estimat- ed to have a maximum capacity of 600 containers in and 600 out per day. This assessment of capacity was based on stacking containers 2-high. The recommended layout allowed space in the marshalling area for the storage of 300 empty containers per berth, for con- tainers under repair and for workshops.
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