Northwest Fishing Reports

i have a 1973 115hp johnson outboard that i just aquired. I have never owned a boat before with an outboard. the outboard has a damaged "fin" just above the prop. i have no idea what its technically called but i heard i can buy an aftermarket replacement. i cant find any online but several people have told me i can buy them. im sure im just searching for the wrong thing. im not even sure im posting on the correct forum. if you might know what this is called or a solution to my problem that would be much appreciated.

Are you talking about the cavitation plate? Horizontal just above the prop?

i believe so. there are two of them one slighty larger than the the other.

Bodofish wrote:Are you talking about the cavitation plate? Horizontal just above the prop?

Yep, the big one is the cavitation plate. I've never seen an aftermarket one but that doesn't mean anything. I suppose you could put one of those shark fin or whale tail things on there.

I have used the dolphin or doelfin or however its spelled on my last 2 main motors. made a big improvement in how the boat sat while not on plane.

Is it horizontal or vertical?

Horizontal it's the cavitation plate that goes along both sides of the lower unit housing and behind the lower unit above the prop. I've never heard of a replacement part/item.

If it's short and vertical it's bolted under the cavitation plate. Some motors have them, some don't. And there are replacements you can buy. I never can remember what it's called. Torque tab? It helps with the 'torque steer' of the motor.

Thanks i appreciate it guys. obryan214, wheres a good place to pick those up? i might give that a shot before replacing the lower unit.

....You're welcome

Hydrofoil fin, Type that on amazon I think that is what your looking for and what there talking about.

ty096 wrote:Thanks i appreciate it guys. obryan214, wheres a good place to pick those up? i might give that a shot before replacing the lower unit.

the first set for my suzuki came from the marina on black lake, the second for my yamaha came from sportco. any boating supplier should have them.

cabela's and bass pro shops have whale tails, if that's what you need, is the cavitation plate/anti-ventilation plate.

Just remember there has to be enough of the plate left for you to bolt the new fin to. If you don't have enough there you will not be able to attach it and waste your money. Just a fyi.