A few weeks ago I was taking a Sports Diver Student (2nd level course) on a navigation dive. All week the vis had been around 10m, on the day I briefed the student we would leave the surface about 15m from the cliff and navigate by compass to the wall.
As we got under the water and stabilised at 5m the vis had deteriorated to less than 3m. At this point I took the student's hand and guided them to the cliff (the bottom was over 25m (5m greater than I'm permitted to take a SD student).
After the dive they thanked me for holding their hand as it was the first time, in 40 dives, they had been to hold a depth in mid-water.
As we got under the water and stabilised at 5m the vis had deteriorated to less than 3m. At this point I took the student's hand and guided them to the cliff (the bottom was over 25m (5m greater than I'm permitted to take a SD student).
After the dive they thanked me for holding their hand as it was the first time, in 40 dives, they had been to hold a depth in mid-water.