Single pull macgregor type hatch cover.pdf - Cochin University of ...

2.5 PIGGY BACK
2.5.1 Description
Figure 2.5 Piggy type
Source: - Walter Vervloesem - IMCS
Lift and roll covers are a development of rolling covers and example is illustrated in
fig. Each covers consists of two panels, one of which has powered wheels. In the way
of the ‘dumb’ panel, four hydraulic rams which act vertically upwards are fitted with
the coaming. These engage in lugs on the side of the panel to lift it high enough above
the coaming for the motorized panel to roll underneath. The dumb panel is then
lowered onto the motorized panel so that both can be moved together. The side
coaming can be extended so that the two panels can be stowed beyond the hatch end.
Alternatively these covers can be side rolling, stowing abreast the hatchway. There is
in the theory no limit to the size of these covers composed of two 100-tonne panels
for 26m by 23m hatch ways have been supplied for forest product carriers.
15