Aquaculture Engineering

Practical - 2
Experiment No 2 - Obstacle to chaining but not ranging

There are two types of obstacle in this case

• When it is possible to chain round the obstacle. E.g., pond.
• When it is not possible to chain round the obstacle. E.g., river

When it is possible to chain round the obstacle

PQ is the chain line. Select two points A and B on either side of the obstacle. Setout equal perpendiculars AC and BD. Join CD and measure it. AB = CD.

When it is not possible to chain round the obstacle

AB is the chain line. Select a point ‘C’ on the line and draw perpendicular CD to it. Bisect it at E. Erect a perpendicular to the line CD at ‘D’. Range ‘F’ in line with GE and measure DF. Then GC = DF.