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

CHAPTER 3 - GENERAL REQUIREMENTS
3.1 REGULATORY REQUIREMENTS
3.1.1 Rules Governing Cargo Access Equipment
Cargo ships exist to transport goods from one port to another to accomplish this; they
must have some means of getting cargo into and out of their holds. Thus ships must
have opening either in the weather deck, as in vertically loading vessels, or in the
bow, stern or side, as in horizontally loading vessels. These areas are all vulnerable to
damage at sea. Thus cargo access equipment must provide access in port while
keeping water out, during voyage. One of its prime functions is to ensure the safety of
ship, personnel and cargo. In order to maintain acceptable standards of safety at sea,
rules and regulations have been introduced over the years, many of which directly
concern access equipment.
3.1.2 International Load Line Convention, 1966
Probably the most important regulations that affect access equipment are those arising
from the 1966 load line convention which replaces the first international load line
convention in 1930 for determining the freeboard. It provides for two categories. It
provides for two categories of ship for freeboard purpose-Type. A ships which are
those designed to carry liquid cargoes in bulk and whose tanks have small access
openings and Type B which includes all other ships. Among Type B ships are certain
bulk carriers and ore carriers which are further sub-divided as follows:
(a) Ships of over 100 m length having steel hatch cover on all exposed hatchways
and which can remain afloat in satisfactory equilibrium with any one
compartment flooded. When the length exceeds 225 m, the machinery space is
also treated as a floodable compartment. These ships can have table B
freeboards given in table B and A summarized in table; such freeboard is
referred to as B-60.Tables A and B referred to the minimum freeboard laid
down by the Convention for type A and Type b ships.
(b) Ships which can withstand flooding of two adjacent compartments may be
assigned B-100 freeboard, virtually equal to type A ships.
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