Aim forward of the berth as the stream will push the yacht sideways. Approach at a shallow angle. When in position, angle the yacht so that the stream moves her sideways.
stream
Aim too close to a downstream boat and the stern may collide with it. Ferry Gliding
Ferry gliding is a useful way to get into a tight berth when stream is present. The term describes stemming the stream and making the yacht crab sideways into a berth.
stream
Stemming the stream is achieved by motoring into the stream so that the boat is not moving forward or backwards. A transit abeam is used to check. To move sideways, keep the transit while steering slightly towards the pontoon. Water flowing over the rudder allows steerage, and tide pushing on the bow and hull moves the boat sideways.