Simple pipe-drag sweeping device using iron-pipes.
In hydrographic surveying depths are measured by echo-sounders. It is well known that there are many doubtful sounding records and it is very difficult to examine and interpret them correctly. The author has designed simple sweeping devices, rope-drag and pipe-drag in imitation of the wire-drag,and made experiments on them several times. The pipe-drag is considered to be more useful than the rope-drag. The sketch of the device is shown in Fig. 1. The iron-pipe, composed of four identical component pipes, is 10 m long, 50 mm in diameter and 40 kg in weight. An aluminum buoy is connected to each end of the pipe by a depth rope. Two ropes connect the ends of the pipe and a pipe-depressor which is connected to the towing rope in order to lessen the rise of the pipe. And the towing rope connects the pipe-depressor and the surveying launch. A buoy to which an echo-sounder is installed is also towed by the launch just above the iron-pipe in order to record the depths of both the pipe and the sea-floor. Another echo-sounder is installed to the launch itself. Accordingly the sea-floor is recorded double as shown in Fig. 7, 13, 14, 15. The records of the pipe are shown in Fig. 7, 12, 13, 14, 15 which show that the pipe could be towed at a constant depth. In Fig. 13 the pipe cut through the doubtful record, which indicated that the doubtful record constituted no danger to ships although its structure remained unknown. When the pipe was caught by an anchor-rope, the launch could not go ahead. When the pipe bumped to a protrusion of the sea-floor, strong shock came to the launch through the towing rope. When the pipe bumped to a wood which is projecting from the sea floor, the pipe broke at the connection part of the component pipes. The pipe was repaired afterwards. Thus the pipe-drag by a single survey launch is considered to be useful for the examination of doubtful echo-sounding records. The author reports about the construction of the pipe-drag and experiments on it.
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| Format: | Journal Contribution biblioteca |
| Language: | Japanese |
| Published: |
1971
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| Online Access: | http://hdl.handle.net/1834/16351 |
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