Here, you can see the seal completely raised and the boat is able to sail out into the open river.
I was amazed at how little water escaped from the lift when it was in operation; just a few little drips. This compared massively with the large spurts of water that escape through the canal locks when they are being used.
Again, I hope you don't mind my "playing around" with your lovely photograph!
In Photoshop Elements 11, I used a layer mask in Levels and selectively lightened some parts of this lady's face - oh, and some of her clothing too - to try to reduce the strength of some of the shadows. Quite difficult to do on a small image but would be much easier on the full size original one.