by ghiribizzo » Mon Jun 11, 2007 10:11 pm
I asked the-man-who-knows in Greenock and mentioned the Skelmorlie markers.
He replied:
They are starting and finishing points for a measured mile. The newly made ship would sail past under full steam and they would be able to accurately assess the speed of the craft.
They would also use it to assess acceleration and stopping distances.
There was another set downriver at Skelmorlie. In that instance rather than using lights in a box, they would line two posts up. One would have a V shape and the other a ^ shape. They would make a diamond when it was time to start the clock.