Puzzled........ my 1st bent prop?

[Ks]

Well it was bound to happen.

At least it happened at the end of the day on the return trip to the dock.

Here is what happened:


Cruising about 25-30 mph in very deep water ( 300ft plus) all of sudden hear and feel a loud noise, crunch ...bam....... and then the boat vibrates horribly, I stop look back and a piece of drift wood about a foot or so long pops up to the surface. I did not go back to inspect it, I wish I had now. I would not call the piece of wood large and It must have just been under the water surface, why I did not feel it hit the tracking fins is beyond me.

Anyways, tried to power up and a soon as we got over 10mph and 3000 RPM the boat would shake and vibrate. the shaking was so bad, we could not go over 10 mph. got the boat back on the trailer after limping back and I was amazed I can not see any damage or nicks to the prop?

I searched the forums, and everyone describes the lack of power and vibration when a blade folds completely over mine still looks new.

Did I or could have I bent my shaft or strut? or can a unseen bend or tweak to the prop make that much of a difference?

I have the weekend kit that I bought last year from SFFAN, So what is the procedure? should I change the prop out? or should I take it to my dealer the check the strut or shaft? is there any tell tail signs to look for with the prop and or shaft to find the tweak?

Any ideas? or suggestions?

Other then that we had a awesome two days or boating, I will post pics in another thread

[maximus2003]

We were on the same lake with KS, only about five minutes behind him & the same thing happened to us as well. Please help!

[Bandsecurity]

I have had this happen to me recently but I think I caused more damage by bending the fins. You may have bent the shaft or knocked the motor out of alignment. Even a tiny variance in the shaft, prop or motor alignment will cause the vibration. I experienced the same vibrations you did. I had the prop repaired (250) and the engine aligned as part of the 20 hour service and the vibration disappeared. My shaft is 3/1000's off but does not cause any problems and I will have it fixed at the next service interval. As long as the shaft is not too bad you should be fine.
http://www.tigeowners.com/forum/showthread.php?t=6361
I would switch out the prop and take it to a prop repair shop to check it out. I would also have the engine alignment and shaft checked before heading out unless it easy for you to drop it in the water for a quick spin.

[dogbert]

This happened to me. While the prop had some minor damage, the big damage was to the shaft, strut and rudder. What happened was that the log that I it managed to wedge itself between the prop and the rudder, thus bending the shaft one way and the rudder the other. $1,700 later, it was fine. Good thing my State Farm agent was on the boat when it happened. They covered prop, shaft, rudder and strut.

I'd check with your insurance agent.

[Ks]

Well pulled the prop off and everything is fine there, I am a little bummed as I was hoping it was just the prop

Unless I measured wrong? I placed the prop on a flat surface, ( all 4 points where perfectly touching the surface) I then took digital calipers and measured from the left side and right side of the shaft hole. It was about 1/4 of a mm out, I would suspect that is within tolerance.

by eye the shaft looks to spin true, I am wondering if it is something else now..

any idea?

I have 15 hours on it now, so maybe time for a early 20 service to check the motor mounts and everything else.

[eks]

Well pulled the prop off and everything is fine there, I am a little bummed as I was hoping it was just the prop

Unless I measured wrong? I placed the prop on a flat surface, ( all 4 points where perfectly touching the surface) I then took digital calipers and measured from the left side and right side of the shaft hole. It was about 1/4 of a mm out, I would suspect that is within tolerance.

by eye the shaft looks to spin true, I am wondering if it is something else now..

any idea?

I have 15 hours on it now, so maybe time for a early 20 service to check the motor mounts and everything else.

Sorry to hear KS, I hope you find the problem. When I had my 4-winns. I had vibration problems, my prop looked just fine but it had a "NOT NOTICIBLE" bent on it. Once I replace the prop the vibration went away.

I am not saying that it is a prop for sure, but my little experience would point me on that direction.

[Ks]

EKS-

you could be 100% right, I have never hit anything before so this is all new experience. The thing that pisses me off is how small the piece of wood was, I looked back and this thing was a branch ( 2 foot long and about the 6 inches wide) I just cant see this thing bending a shaft.

I knew it would happen sooner or later, I almost wished that the prop would have folded over so it would have been as clear as mud. But now I am searching for the problem and that is frustrating.

I wish our local lake would have water@ the ramp I would go try my spare prop but closest water is about 40 minutes right now.

Still might be worth the drive for peace of mind as my dealer does not open till Tuesday.

[Bandsecurity]

I'd check with your insurance agent.

I would check with your agent first and find out the ramications of submitting it first. Mine told me that it could impact future rates and if I have another claim this year that it could cause me to get dropped. So you need to weigh it out. I figured I would wait until a claim at the end of the season or one over $2k.

Those props and shafts are very sensitive. My prop was visibly bent but the shaft wasnt and looked good to the eye. If you take it to a prop shop they should be able to determine if there was damage. Your dealer should be able to check the shaft but I understand it is more costly to replace it - about 4 hours labor which is why I will wait until the next service.

If you prop has minor damage you should be able to get that fixed for under $200. The shaft will be more as stated above but you might not be too far out of tolerance if there is no visible damage and you can wait to replace it.

[talltigeguy]

Sorry to hear KS, I hope you find the problem. When I had my 4-winns. I had vibration problems, my prop looked just fine but it had a "NOT NOTICIBLE" bent on it. Once I replace the prop the vibration went away.

I am not saying that it is a prop for sure, but my little experience would point me on that direction.

My bet is on the prop is bent, but you just can't tell.

I assume you have an Acme prop? The nibral folds fairly easily and that should protect the shaft in this sort of strike. It will be the first time I have seen a prop strike spare a nibral prop and take out the shaft, if that is the case. It usually is the prop only, the prop and shaft, but never the shaft only, unless you are running a stainless prop.

[Ks]

Thanks for the advise about the insurance I will keep that in mind if it gets that far.

I am gonna take it to the dealer on tuesday and get them to look at it. right now the boat is un usable over 10 mph so pretty much have to look into this right away.

[Ks]

My bet is on the prop is bent, but you just can't tell.

I assume you have an Acme prop? The nibral folds fairly easily and that should protect the shaft in this sort of strike. It will be the first time I have seen a prop strike spare a nibral prop and take out the shaft, if that is the case. It usually is the prop only, the prop and shaft, but never the shaft only, unless you are running a stainless prop.

Acme 537, I don't think any of the new boats come with stainless anymore.

I will take pics and post after dinner. Maybe someone can see something I can't.

thanks

[TRD]

You would have to put an indicator on the shaft to see if you have runout. You can check your prop the same way. Find or make a shaft the same size diameter as you prop hole dia (about .0005" to .001" smaller). Put the shaft between some v-blocks or something that will let you prop spin. Put the indicator on it several places and it should be the same. You will see a problem if there is one.
I would check you shaft first but I would assume you would need 2 indicators to check 2 different places at the same time to check for alignment. I am not sure how else you would check that. Good luck. Hope it all works out.

[scoot18]

It probably is the prop and it's just hard to tell. Keep in mind if all four of the blades struck the object they may have all bent the same way, all four could look consistent and still be out of whack and cause a vibration.

I had a time last summer that I hit something in the water and it bent all four blades, every one was curled over just slightly and the vibration was horrible, got up to about 15 or 20 mph and it just made me cringe. I got back to the ramp & loaded the boat on the trailer tried straightening the blades, I got them much better; got it pretty close. I put the boat back in the water and it still vibrated it's a## off. That then sent me looking for another prop to try and salvage some of what was left of the long weekend.

Good luck

[da.bell]

Ks, sorry to hear about the boat. hitting a log in the middle of the lake must have sucked big time.

[ctcranor]

KS, we did the same thing last year. Hit a small branch (about the size of a baseball bat) and the vibration started at +15mph. Put it on the trailer and couldn't see, or feel, anything unusual but knew it had to be the prop. It was, luckly, the prop and we were fixed and back on the lake in a few days.