so im driving my friends boat he just got its got a 200hp yamaha on it and a hydro fin. It seems hard to steer to me and when you come out of the hole sometimes it like it loses its torque. do u think its the tranny or fin? and why would it be so hard to steer?

If it's cable steering, I would suspect one or both the steering cables.   Take one end the rod loose that goes from the end of the streering cables to the motor.   Motor should pivot back and fourth with ease.

When coming out of the hole, did you have the motor trimed all the way in, may be cavitating, even though a foil usually will hellp prevent that.  Make sure prop is not banged up also.

his prop has a dime size chunk missing out of it on one blade.

I'm pretty sure a dime size chunk would probably create some problems.

The chunk out of the prop blade most likely has nothing to do with the hard steer but it sets up vibration that might not be felt but rest assured the lower unit bearings and seals feel them. I'd get that prop fixed now. He might want to consider a spare. I carried an aluminum spare for years just in case I broke a prop.

I don't know your experience level with a performance boat so I'll start from the beginer level. Tuck the motor all the way under to start. When you get on plane trim out slowly until the boat goes with out steer torque.

With my boat I back the throttle off to about 3/4 throttle as I get on plane then trim out until the engine noise gets to a level I can't describe but I call sweet. When I hit the sweet spot my boat will run without steer torque. It also won't porpoise unless I slow to much. If it starts to porpose either give it a little speed or tuck the motor under a bit.

I don't think the tranny (a lower unit gear box on an outboard) or the fin are a problem. I don't think you have the boat trimmed properly. Many over trim so don't be guilty of that. A rooster tail much higher than the engine cowling is too high.

I repeat I'd get that prop fixed or replaced pronto.

With a dime size chunk missing makes it sound likes it's an aluminum prop.   If so, remove it, put it in the back for a spare and get a good stainless prop matched to the type hull he has (you don't need a high lift prop if it's a boat that's not going to be able to use it).  He will see a hellava difference in hole shout and overall performance.