By Lucy Kenningham “Looking out at the river, I was struck by how empty it was,” Sean Collins tells me. This was in 1994, when he had just been made redundant from his previous role as an apprentice waterman on the Thames. All that empty water stretching through the middle of London – it was a “waste”. But he had an idea. In 1993 the firm he was working for, Thamesline – which ran a boat service from the developing docklands to the City – had disbanded. Its main backers Olympia and York (the property developers behind Canary Wharf) had gone into administration and saw the not-for-profit partne…