Hi Mark, Mailed you directly, but one way to model this could be as follows:
See attached, a simple example of how it could be done:
I inserted a part representing the bar/Scale in this assembly containing 2 components, - one moving, - added a plane to the moving component to have a fixed position and inserted an assembly cut referencing/placed on the plane, cutting the bar. As it now moves in motion the cut moves with it – resulting in a sliding bar.
I added a parametric note in the model for the fun of it – I first added the reference dimension into a custom property first - then linked a note to this custom property, - this way you can choose font and colour of the text as well.
I think with a bit of arranging you could get a reasonable result.
Hope this will give you some inspiration.
I would do the same thing as Flemming has suggested. You can link the two distance mates and as the boat move away, the plane for cutting the bar would move along. This would be best and easy way to accomplish what you are looking for.
Nice animation btw