Bent Keel Fin..Would that make boat shake???

[yellowMIL]

Who found a stump over the 4th..........
I think I came across something it the water over the 4th. My third “keel fin” is bent out of place about an inch. My first question is, would that makes the boat shake?..1990 SNCB …Pulled the boat out looked over the prop and shaft looked fine, how to test aliment on the two……thanks 1990SNCB 351motor
...Thanks you to all the men and woman of the armed forces…

[GCSuper]

I ran a Ski Centurion for years with a bent fin. Never could tell anything was wrong. Even had a shop look at it and they told me if it ain't broke, don't fix it.

[azeus17]

I don't think the fin would cause the boat to shake. It might make it want to pull one way or the other. I would say check your alignment. There are some very well written "how to" posts about alignment. If you can not find here on PN, head over to correctcraftfan.com. I know there is one there for sure. Also, double check you prop. It does not take much to cause a vibration.

[yellowMIL]

So , I'm guessing the next step would be to start looking at the Strut and see what is out of line, because it did not shake before...

[HS]

Does the shaking vary with engine rpm? If so, I would be thinking shaft or prop.

Now that I look at your photo #2, the blade in the top right looks like it has mor space around it than the others do. Could Bethesda angle of the photo, but the top left looks like it has the same overlap with its adjacent blades that isn't the same with the top right.

I have read that a misaligned shaft or bent prop that causes a shake can become a problem with the transmission, etc.

[Rick]

I would worry about the prop more than the strut. A shaking or vibration will be caused by a bent prop or shaft. If your lucky you just dinged your prop. You can take it off and have it rebalanced and trued, or you can replace it. If a new prop doesn't fix the shaking I would pull and replace the shaft. Lets hope its just the prop.

[yellowMIL]

HS "Senior"........ The photo was square as possible, but will measure the blade distance it does look funny……When the large sound happened “ clunk or bang” I just put in gear so it was low rpms…..Have old 3 blade will change out this weekend …..thanks for all the input…

[east tx skier]

As others mentioned, fin shouldn't cause the shake. You probably nicked the prop if it isn't obviously bent. It doesn't take much.

For the tracking fin, my local dealer has a fin straightener otherwise known as a 4x4 post with two handles carved into it. He gives it a couple of good whacks and it is straight as an arrow.

I Orka'd a fin last year and had to replace it. When I did, I noticed that another was out of alignment, which is how I came to know of the crude, but effective and inexpensive fin straightener that my dealer has in the back.

Frighteningly, the unorthodox methods are extremely effective.

[djmekinac]

There seems to be a nick on the top right blade, that would mean it is bent, that will cause a vibration for sure. I had a minor bent last year just from the blade (not spinning) being pressed against the lower member of our boat lift and sure enough there was a vibration.