GB874263A - A device for computing the probability of collision between two vessels - Google Patents

Abstract

874,263. Indicating courses and bearings. AVEL CORPORATION GENEVA. Oct. 10, 1957 [Nov. 21, 1956], No. 35652/56. Class 97(2) [Also in Group XXXIII] A device for location in one vessel and for computing the probability of collision between this vessel and another one moving in the same horizontal plane comprises means settable in accordance with the speed and course of each vessel, and with the bearing of the second vessel from the first vessel, said device also including means to compute whether the components of the speeds of the two vessels resolved in a horizontal direction perpendicular to the line joining them are substantially equal. As shown, the device comprises a compass card 100 freely mounted on a spindle 101 so as to turn under the influence of magnets 102, and a card 105 having a pointer 106 which in use is pointed towards the other vessel and co-operates with the compass scale on the card 100. This card 105 is rigidly mounted on the spindle 101 and has a peripheral band divided into sectors 107 to 110. Diametric line 111 on the card 105 passes through the pointer 106 and divides the surface of the card into equal sectors 112 and 113 which are coloured green and red respectively. A series of parallel lines 114 are marked on the card parallel to the diametrical line 111. Mounted above the card 105 is a disc 115 which is fixed relatively to the vessel carrying the device and has a diametric line 116 forming a lubber line which co-operates with the compass card 100 to show the course of this vessel. A speed scale 117 is marked along the line 116 which terminates in a pointer 118 provided with a window 119 overlying the sectors 107 to 110 on the card 105 and immediately adjacent to the window 119, two further windows 120 and 121 are provided in the edge portion of the disc 115. This disc is transparent, and the semi-circle thereof to the right of the line 116 is coloured green while the other semi-circle is coloured red. A central shaft 122 passing through the hollow spindle 101 carries at its upper end a pointer 123 provided with a speed scale 124, this pointer representing by co-operation with the compass card 100 the course of the first vessel. The speed of the two vessels are represented by points on the scales 117 and 124 and these points will lie on lines 114. These lines, in effect, form a scale of speeds of the two vessels as resolved perpendicular to the mutual bearing line and an estimate of the risk of collision is afforded by the separation between the two lines on which the points representing the speeds fall. If the pointer 123 indicating the course of the first vessellies in a sector where the green of the disc 105 is overlaid by the green of the disc 115, the two vessels are moving on convergent courses. In the event of avoiding action being necessary, then the action to be taken is that shown in the window 119 by one of the sectors 107 to 110 of the card. These sectors may, if desired be differently coloured. Specification 874,261 is referred to.