Safety air drought (SAD)
Air drought is distance over ship, when manoeuvre under construction. They mainly consist:
- Bridges (road, railway) over waterway .
- High voltage lines,
- Pipelines over waterway,
The condition of safety ship movement is following.
HS < HC
HS = the height of highest point of ship and
HC = the height of lowest point of construction over waterway.
- In many cases, the sea-river ship’s superstructure is regulated. It permits to decrease of ships height. Also other elements of ship’s construction can be disassembled – for instance masts of radar antenna, radio etc.