Re following link - officially its not alllowed but its been going on since my first paddle steamer trip in Switzerland in 1975 and probably much longer. Youths of the lakes, especially Lake Leman, surf on top of the large rudders of the lake steamers until distance from shore or a swift turn of the helm 'encourages' them to depart. Some even hold onto the support spars under the sponsons aft of the paddles and eventually let go when the vessel gets underway - getting washed out of the paddlebox at high velocity. On one occasion a lad's swimming shorts got washed out before he did - he had to swim very fast to retreive them and save his modesty!
Although I was still a teenager in 1975, and was in a group of teenage lads camping in Switzerland, I can't remember any of us wanting to have a go at this!
Crazy Boat Surfers
(Sorry, cannot get YouTube embeds to work here0