Donald Duck was used as prior art to invalidate a method of ship raising. This was discussed at length on HN six months ago: http://news.ycombinator.com/item?id

Donald Duck was used as prior art to invalidate a method of ship raising. This was discussed at length on HN six months ago: http://news.ycombinator.com/item?id=2232857 http://news.ycombinator.com/item?id=2232857