All the following is true except that（）.
- Ain many places a counter current flows in opposition to the main current close to the bank
- Bcurrent can vary with depth of water and large deep draught ships can experience different current effects at differing parts of the hull tend to turn to the wind
- Cas speed is reduced，the increased proportion of the ship's vector which is attributable to current will set the ship close to obstructions
- Dwhen close to the berth in a head current，there is a danger that flow inshore of the ship becomes restricted and the ship is subject to interactive force