i agree that the prop may be a problem but 180 hp isnt a lot shoving around a 22 foot boat rigged for fishing...i'm guessing the boat was never a race day winner but runs ok and youre just looking for something to get it up on plane quicker than it has in the past...
if you are running in your recommended rpm range with your current prop the whale tail isnt a bad place to start from an economical standpoint...although trim tabs have many advantages under different load and weather/sea conditions...
in my experience with 2 previous boats...penn yan 21 tournament with 175 hp merc and 245 hardtop with 205 hp merc a stingray hydrofoil on the lower unit snapped the boat on plane faster, increased top end speed and fuel economy...the time to plane was the biggest improvement and very noticeable...
its an inexpensive thing to try and ive had good results with it...