| 摘要 |
A new pilotage method is disclosed by using pilotage marks. It is fixed to canal bed, or bottom of channel or sea bed... etc, and it is exectly on equal distances and have an enough height to be shown very clearly on ship echo sounder (sonar) at fixed time intervals while ship speed is fixed by SOG or GPS. So if we imagine the ideal course (degrees and position) so that the ship is completely safe, we can call this course the optimum course, so if we think that the sun rays are perpendicular on this optimum course, it will make a shadow on the bottom of the channel exactly. So if we use this shadow on the floor (canal bed) as a course completely the same optimum course on water channel surface, and if we choose determined points with fixed and equal distances and fix the new created pilotage marks on these points, so it will be received very clearly by ships echo sounder (sonar) as long as the ship is on the optimum course and if it is still using its degrees and position, but in case the pilotage marks disappeared, it means that the ship will be away from the optimum course even if it is back to same degrees of it, and ship will not be safe (drifted or shifted). In this case it must be corrected again to the optimum course, and to be sure that the pilotage marks will be shown clearly on ships echo sounder (sonar) again as early as possible.
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