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

The first horizontal rolling built to the design patented by MacGregor &
king Ltd. Was installed over the aftermost hatchway of the 9000tdw motor ship
sheaf holme which left the Sunderland yard of her builder, Wm. Pickersgill, in
August1929 amid rather more publicity than she would otherwise have merited.
The event was important because it was not the first time that a hatch cover had
been put into service that was easily operated manually, yet depended on
tarpaulins for water tightness nor did it forgo any of the strength with which
previous steel covers had been endowed.
The earliest horizontal rolling covers produced by Macgregor and king
(subsequently known as Macanking) came in two forms, although both were
basically similar. The first was fitted in fairly small hatchways and consists of two
moveable sections fabricated out of steel plate stiffened by channels bars or bulbs
angles, with a skirt around their perimeters which rested on the coaming when the
cover was closed. They revolved about eccentric bushes which could be rotated so
that the clear height of the lower edge of the cover above the coaming could be
varied.
In the closed position, with the hatch secured for sea, the bushes were
aligned so that the perimeter of the cover rested on the coaming throughout its
entire length. To open the hatch, the bushes were rotated through half a turn with
a marlin spike, thus raising the cover so that it could be easily pulled along on its
wheels. This arrangement has become a feature of many MacGregor hatches
since.
In France in 1934, Captain Mege, of Louis Dreyfus Cie, patented folding
steel hatch covers which were first fitted in the cargo ship Louis L.D. two years
later. They considered of double panels hinged together and to the end coamings,
but, unlike the von Tell covers, they were opened by lifting the panel nearer the
coaming hinge. As it was raised, the second panel was pulled towards the end of
the hatchway, supported on two trailing wheels which ran along the coaming,
until both panels were stowed together vertically. In this way a folding hatch
cover could be opened in one operation instead of two. Fig 1.2 shows an early
Mege folding steel hatch cover. Closing was carried out by simply allowing the
fold hinge to open under the combined weight of the two panels until both were
in position resting flat on coaming to which they were secured by bolts. In long
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