It has been my experience that the fin on the rear cowl is something else that will break off depending on what the boat does when you dump it. Of course the removable cowl usually comes off, but if your dump is violent enough things will break. The Thunderboat I have been running for a lot of years has been dumped a few times and I believe I have broken the fin only one time. I think the fins make the boats more realistic looking like the big boats. I assume that they were on the big boats to help counter the propwalk of the boat at speed. Just my opinion.
Dick Tyndall
Crashed several times it always hung on.
