I’d been told to accelerate hard out of the sea lock, but I’d also understood the reason. The tide was rushing in up the river, and so as soon as our nose got in to the stream it would get taken sharply off to the right. The best way to reduce the effect is to have 20 tonnes of boat already going the other way. So I smoothly pushed the throttle much further than I ever do on a canal and we drove in to the stream with aplomb.