They were not made with longevity in mind and as a pontoon with a truck chassis hanging out the bottom there are loads of rust traps. Used to be 10's of these at the stores near Tewksbury, where they auction them off. Many were already duff and I remember seeing one, newly acquired, barely leaving the Thames in time, as the weakened areas failed in action. They do not have great freeboard. They are notorious for being hard to restore. There was a pink one for sale for ages for around £54k. Not sure it was not on the Mersey. A pink one used to be at Wickstead park. I believe there are several at Morecombe bay somewhere in case they can get to stranded people. They have Argo too. However if your in a really unstable area even these cannot get out as they get stuck and the suction of the sand is quite dramatic enough to swamp the rescuers. Part of the reason the Chinese immigrants sent out cockling could not be rescued. Nasty business. A rare sight now, is a DUKW.