okay... in my defense... it's been awhile since I've been in my Revo... been using the PA a lot. Last week decided to do some pond fishing and loaned my PA to a friend... I used the Revo. Launched no problem, trucked down to the end of the pond (about 200yds) , noticed a funny kind of shuddering vibration on the MD but was clipping along pretty good... fished the far end of the pond, pedaled back ... still thinking how quick the Revo is compared to the PA. Got BACK to about where my launch point was and started chunking my fly... saw something up against the bank, pedaled over and thought "Crap - somebody lost a fin!" .... pulled my drive and guess what.....? I'd pedaled OVER 400 yds on one fin!!.......Re-installed it right there and no problems rest of the day. Inspected it very closely... no rips or tears... nothing... how did I throw a fin without damaging the section where the little screw and adjustment nut are?