This type of accident is by no means infrequent. The bottom of the hull at the forward end should be sprung or bevelled upwards for clearance and handiness in working, and the bottom from the bows aft to the position of the ladder at the “ maximum dredging depth ” should have the thickness of planking considerably increased to obviate accidents through logs being caught in the buckets, and by their being dragged upwards through the bottom. Very often the bows are sheathed with steel plates as a protection against blows and chafing. The bows of a paddock dredge should be well rounded to permit of being easily manipulated in a corner, and should also be more heavily planked and framed than the other pontoons, so as not to be damaged by striking a face, as the dredge surges at her work. with twenty-four hours fuel on board and the dredge gear. Of course, square bows offer much greater resistance to the current and require heavy lines to hold them, but as a dredge is not built for speed, resistance is not taken into consideration to any extent beyond the usual practice of making the floor of the pontoon take an upward curve at the bow.Ī paddock dredge should draw as little water as possible, and the draught should not exceed 5 ft., even in large dredges a fair average draught is about 3½ ft. It is, therefore, not provided with a projecting ladder to eat into banks, nor with sharpened bows to work into corners but, as a rule, is built square across the bows, especially if working in a current such as runs in the Molyneux in New Zealand, for the practice there has proved that a square-nosed dredge remains steadier in the current, and does not “ yaw ” about so much as a sharp-nosed one. The river dredge is designed to work with some depth of water underneath it, and is not called upon to cut its own flotation. The type of a Dredge is defined according to the Nature of the Work they do. Under this heading bucket dredges may be classed as: River dredges paddock dredges.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |