Boyd's Automatic Tide Signalling Apparatus - The Automatic Tide Marker Station - How IT Worked

How It Worked

The system entailed the provision of a floating chamber, or 'Tide gauge' (at NS 30369 37993) in this case made of timber, situated at some distance from the structure and calibrated in such a manner as to represent the tide depth at the harbour bar. In the case of Irvine, the bar and the flotation chamber are some distance apart. Within the chamber a wooden float like a raft rose and fell according to the tide. Attached to this float was a cable, which ran through a wooden trough to the building, named the 'Pilot House' by the locals (at NS 30386 37970) which housed the apparatus. Changes in direction, the difference between the actual tide heights and the distance between the balls/lights, was achieved by pulleys and gearing. Within the building the cable was attached to eclipsers, metal frames with wheels which ran on rails attached to the building. The eclipsers, two in number, rose and fell with the tide. As the eclipser rose, it covered apertures through which a gas light had been previously observed. This light, from the main gas supply, was automatically switched off as the eclipser continued up but a by-pass jet always remained alight to maintain a supply to the main jet when the eclipser descended. At night the tide depth was indicated by the use of lights which diminished in number as the tide went out and vice versa.

A code of different colours controlled by the blinds was used. During the hours of daylight, the method of indication was a code of black balls which were fixed to ropes connected to the eclipsers. These ropes were passed over pulleys attached to a cross arm on a staff at the top of the building. The balls were connected at fixed intervals to the rope and, again as the eclipser rose, the rope and the balls fell and disappeared within the building. The distance between each ball was exactly calibrated to tie in with the switching on / off of the lights. To correspond with the change in colour of the lights different shape balls were proposed but never installed. The code of balls / lights indicated by the system involved more balls / lights being displayed as the depth increased, the maximum being twelve balls at 18 feet of depth during the day or four white lights by night.

Adjacent to the Automatic Tide Marker Station building another signal system existed to indicate whether vessels could enter or leave the harbour. On a flag staff, two red lights hung vertically by night or two black balls hung vertically by day, were displayed when a vessel should not enter or leave. At the bar entrance was a white light to the south and northern one which flashed on and off continuously to give skippers their bearings.