Page 299 - Ship Construction.DJ Eyres 6Ed

Ch24-H8070.fm Page 288 Wednesday, October 18, 2006 7:00 AM
288 Ship Construction
reefer ships. The electro-hydraulically powered cranes may have single or
twin jibs and wire or ram luffing arrangements. These cranes may be posi-
tioned on the ship’s centre line, but this may require an extremely long jib
when the ship’s beam is large and a reasonable outreach is desired. Pairs of
cranes at one end of the hatch or at opposite corners of the hatch and with
an ability to work through 360 degrees can provide a full range of load/dis-
charge options for a ship.
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Feeder container ships may be fitted with cranes, with say a SWL of 40
tonnes, to facilitate loading/discharging containers in ports where container
handling facilities are not available ashore (see Figure 24.6). These cranes
งานห้องสมุด ศูนย์ฝกพาณิชย์นาวี
may also be used for handling pontoon hatch covers and are generally fitted
to one side of the ship (see Figure 24.6) with the structure below substan-
tially reinforced to carry the loadings. Bulk carriers that are not trading on
fixed routes often have centre line mounted deck cranes of say 30 to 40
tonnes capacity, between hatches, on a Handymax bulker, for grab handling
the cargo and lifting hatch covers. Figure 24.7 shows in section the arrange-
ment of one of three 30 tonne SWL wire luffing cranes fitted to one side of
a 70,000 tonne deadweight bulk carrier. This crane installation allows the
ship to tranship cargoes outside draft restricted ports. The three cranes in
this instance being capable of handling somewhat more than 10,000 tonnes
in a 24 hour period. ึ
Tailor made heavy lift cranes of 400 tonne to 800 tonne capacity have
been supplied for offshore and heavy-lift ships. In some cases the latter

3–30 tonne S.W.L. wire luffing
cranes mounted on 70,000 tonne
deadweight bulk carrier

FIGURE 24.7 Cross-section of bulk carrier with side mounted 30 tonne wire luffing
cranes