I fish a small river in Iowa and always seem to come across shallow rocks, sandbars and logs. I just bought a new 15 hp 4 stroke Mercury and I want to protect it as much as possible. Have any of you guys used this "Macs River Runner Prop Protector" on your motors? I am pretty sure I should invest in one for my situation...i just wanted to make sure it was worth the $90 bucks and was wondering if you guys had any problems with them such as performance or durability or anything like that. Your thoughts are greatlly appreciated.