It's easy to be complacent about locks and believe that only hire boats or inexperienced crew are likely to get things wrong. However in July, we were descending Stockton locks and were sharing one of the locks with another boat. I usually try to keep the boat in the middle of the lock and so I was a bit surprised when the boat beside us was put in reverse and was slowly moving back behind us. All of a sudden the chap shouted that his boat was caught on the cill. This was very alarming as I couldn't do much to help. After the emergency was over, he turned to me and said "There, that's what can happen with six years' boating experience. It's never happened to me before". So we moved to the next lock down and whilst in it, my brother in law came up to ask me what had happened, so I was explaining to him that the other boat had gone too far back and got caught on the cill. Suddenly my brother in law noticed that the boat was again reversing and was just about to repeat the experience and shouted to the chap "Quick ! Stop! You're too far back". We were glad to get to the bottom of the flight without further incident. I wondered afterwards if the man had a problem with concentrating.
What was quite a shock though was when I found out later that his little granddaughter was sitting at the front of the boat doing some colouring, when the bow was pointing downwards.