Purpose of the whale tail is to provide lift at the stern. 50hp on a pontoon, makes it wishful thinking
These two are spot on. I ran a dole fin on my previous boat (17 ft sea ray 3.0). It did help with planing until it cracked my cav plate…I am thinking it is just additional drag on your pontoon. I would suggest running it with and then without. My bet is you will leave it off.
It's been more than 8mo since Bellasdad was on iboats,Never had a use for a whale tail, Usually used as a bandaid for other issues. That said, run it and see, unbolt and run again, Post your results.