10.
86
Type B. Blocks.
Preparation of Line.
pressure on the harbour bottom.
The base of the block would have projections to increase the grip on the harbour bottom, and a reinforced concrete overhang or no se would project from the ends at the upper surface, to prevent the blocks being over-ridden by the pipe, in the event of it being hooked and lifted by an anchor. Hooks would also be provided in each block for wire attachments for alignment and measuring purposes.
Type B. composite blocks which would weigh 174 tons
in air and 92/3 tuns in water would be composed of 8 to 1
cement concrete and would be in the nature of two blocks
joined together, with an archway in the centre for the pipes to pass through.
hey would have an overall base of 12' x 7'6" and a height of 5'6", the central passage or archway being 4'0" wide and 4′0′′ high at the centre. Hooks for alignment and levelling puroses would be provided at the ends, while the base would have projections to give a better grip and special slinging hooks would be provided for setting.
The advantage of Tvpe B. blocks is, that they foru
a much heavier and more effective anchor than Type A. with a lesser proportional quantity of material, the disadvantage being that in the event of considerable settlement the blocks might eventually rest on the pipe.
From the information available there would appear
to be little risk in employing Type B. blocks, as in the event of settlement, the blocks could be lifted and relaid
on a broken stone foundation.
While the blocks were being manufactured, the
line would be carefully set out on the harbour bottom and
small position blocks would be set at the positions selected