Cleanin' Windies

I had the tow path to myself until three cycles emerged from under a low road bridge, a young couple and an older man blinking in the sun. The path narrowed and curved to the right but the lad in front went straight on, down a wooden ramp onto a floating metal pontoon moored alongside the canal as a temporary dock. He briefly looked shocked as he realised he'd gone off the path then turned back to grin at the other two, raising an elated fist and whooping in delight. And almost immediately splashed off the end of the dock into the filthy weed-covered water. The girl jumped off her bike and rushed to the edge of the canal. The older man stayed with his bike and called "you say he went to university?" She said "come on, help him, he could catch something in there or drown even". Ignoring her reply he continued "...fer what? Cleanin windies?"