Parked up on the ramp at Renton was what appeared to me to be a de Havilland Canada Beaver on floats.  However, it looked different to every other Beaver I have seen.  This one seemed to have a fun that was cut right down.  Initially I figured it needed a repair but then I realized that there was a large dorsal extension to the fin.  This would compensate to some extent to the missing top but whether it is a good configuration, I can’t say.  It didn’t look good to me but it looked airworthy so maybe it flies fine?  Has anyone seen more about this and can share with me some of the history?