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

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Type B ships which are fitted with portable <strong>cover</strong>s, e.g. beams and boards in<br />

position 1 <strong>hatch</strong>ways are required to have their freeboard increased above<br />

those given in table B.<br />

3.1.3 Freeboard<br />

Table 3.1 shows freeboard from the full tables and compares freeboard for different<br />

ships length as required by Load Line Conventions <strong>of</strong> 1930 and 1966.Corrections are<br />

made to cater for non-standard length depth ratios, block coefficient, extent <strong>of</strong><br />

superstructure etc. The standard ratios block coefficient, extent <strong>of</strong> superstructure etc.<br />

The standards freeboard applies in salt water.<br />

Ship length,<br />

metres<br />

Table 3.1 Freeboard for different ships length<br />

Tanker<br />

Freeboards<br />

1930,<br />

mm<br />

Table ‘A’<br />

Freeboards<br />

1966,<br />

mm<br />

Steamer<br />

Freeboards<br />

1966<br />

mm<br />

30 - 250 250 250<br />

60 570 573 570 573<br />

90 1015 984 1070 1075<br />

120 1550 1459 1775 1690<br />

150 2170 1968 2540 2315<br />

180 2710 2393 3230 2915<br />

210 (3080) 2705 3810 3430<br />

240 (3370) 2946 (4310) 3880<br />

300 (3830) 3262 (4755) 4630<br />

Source: Cargo Access Equipment for Merchant Ships.<br />

Table ‘B’<br />

Freeboards<br />

1966,<br />

mm<br />

In designated summer zones throughout the world; slightly different values in<br />

winter or tropical zones in fresh water, or when timber deck cargoes are carried, as<br />

laid down and in the corresponding national legislation, in the United Kingdom. The<br />

merchant shipping (Load line) Rules, 1968. It can be seen that increasing maximum<br />

draft and therefore cargo deadweight. Table 3.2 is derived from the full tables and<br />

shows the increase in freeboard required for Type B ships having portable <strong>cover</strong>s<br />

20

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