The main purpose of navigation is a safe and efficient sailing of the ship between diverse points which require steering the ship movement on a planned trajectory. The accident occurrence of factors affecting the ship’s movement causes its limitation. The ship’s sailing should be safe, so that it does not cause navigation accident. A navigational accident is an unwanted occurrence which can cause loss of life or health, loss or damage to ship or cargo, the pollution of natural environment, damage to the hydro-technological structure, and economical loss due to delay in the port and associated activities.