View Full Version : Hit a Stump

08-01-2010, 07:21 PM
I hit a stump in my Mobius LS today. There is a bad vibration above 1000 RPM, I thought for sure I hit the prop. I got the boat on the trailer and the prop doesnt' appear damaged at all, I believe I bent the steering rudder. It is very difficult to steer and it's hard to turn the rudder by hand. I have a couple concerns, I would like to get the boat fixed ASAP. I assume I get to the rudder bolts by taking apart the storage compartment in the rear? I am also wondering if the prop shaft is bent, since there is vibration?

Any help or guidance would be greatly appreciated.

08-01-2010, 08:01 PM
Follow Up. Found the 4 bolts to release the steering rudder from underneath boat. I am now having a problem removing the steering shaft, or cable. Since I am doing all this by feel, under the gas tank.

Another thing, put the boat in neutral and turned the prop, it doesn't turn easily, but does turn with the same resistance all the way around. How can I tell if the shaft is bent?

08-01-2010, 08:14 PM
Sorry to hear your trouble.....

It may be hard to tell if its the prop or the shaft or both. The slightest issue with the drive shaft or prop will cause vibration. Any vibration is not good. I hit a stump at idle speed with one of my old boats and it bent the rudder shaft, the drive shaft and the prop.

It is normal for the prop to be difficult to turn by hand but it will turn. You'll have to look it over real good. If you can get a spare prop or borrow one you can put it on and try it. Maybe you can rule out the drive shaft that way.

I was able to straighten the rudder shaft myself. I had a machine shop make me a new drive shaft and I sent the prop off to be repaired. I doubt this will be a quick fix. Sorry.... :( Maybe your luck is better than mine....

08-01-2010, 08:22 PM
your luck sounds as good as mine my wife hit a rock and bent my prop today

08-01-2010, 09:20 PM
I appreciate the quick replies. I got the rutter out, it is definitely bent, anyone know where I can get one? Haven't tried looking yet. The prop looks perfectly fine, no nicks or anything. I had just started to accelerate when I hit the stump. Would the bent rudder cause the boat to vibrate? I am just thinking, since I was accelerating, I would certainly suspect to see the prop messed up, if it made contact. By the debris in the water, I assume it did.

08-01-2010, 09:43 PM

Your not going to like the price though....It's nearly 400 bucks.

I guess it is possible that the bent rudder is causing some sort of turbulance but I doubt it is causing vibration.....

08-01-2010, 09:49 PM
Thanks LSM. If I run the boat out of water, will it still produce a vibration without being under load?

I think this is going to get expensive quick...ugh.... Maybe an insurance claim.

08-01-2010, 09:51 PM
One thought.....

I know you are looking at the prop but make sure you look at the base or near the base of the prop as well. Not just the tips. If one blade got hit near the base it could've shifted the blade but not really show a ding or tent.

Also look at the strut where the drive shaft passes through. Sometimes you can look from the side as the shaft passes through the strut and see the last few inches of the shaft bent.

Just thinking out loud......

08-01-2010, 09:57 PM
If you ran it out of water you may be able to learn something if you could watch the prop spin. Maybe....depending on how bad it's bent.

I've not done that before. I'm sure the vibration would be there but I doubt the vibration would feel the same from inside the boat as you mentioned the engine would not be loaded....

08-01-2010, 10:03 PM
Just spent a few minutes under the boat again... The rear support for the shaft and prop appears to be completely bent. I need to find some pictures on here, of that area. I saw some a little bit ago, but don't remember where.

08-01-2010, 10:11 PM
My boat is an 03, I saw somewhere where the strut is suppose to be bent to the left. Wonder how hard it is for a repair shop to find out if it is bent.

08-01-2010, 10:35 PM
I've owned a Malibu, a Master Craft and Now an 06 Moomba LSV plus I've looked at serveral others and I've never seen nor heard of one that is supposed to bent to the left. I feel certain that the strut and drive shaft should be straight in line with the rudder.....

08-01-2010, 10:42 PM
I did the same thing a few months back. Bent my shaft, strut & rudder - I have a stainless prop so it did not damage to that - however I wish I had a different prop, then maybe only the prop would have been damaged.

If there is vibration, I am willing to bet that the shaft is bent, possibly the strut as well.

Good luck! For sure an insurance claim - it was right at $3k for the dealer to fix mine (with some small fiberglass cracks as well that was a result of the stump).

08-02-2010, 12:20 AM
to determine if the prop shaft is bent and or a bent strut...undo the 4- 9/16 coupler bolts between the prop shaft and the trans/or vdrive . check for alignment, rotate 180 degrees and check again....if the gaps change then you have a bent propshaft, if thegaps vary significantly from left to right side you have a bent strut as well.....that is assuming the motor and prop shaft were in alignment before the accident

my .02 only

08-02-2010, 12:23 AM
I've owned a Malibu, a Master Craft and Now an 06 Moomba LSV plus I've looked at serveral others and I've never seen nor heard of one that is supposed to bent to the left. I feel certain that the strut and drive shaft should be straight in line with the rudder.....

the drive shaft is left of the rudder ( or right) so you can remove the drive shaft with out removing the rudder, and to counter the rotational prop forces?

my .02

08-02-2010, 09:33 AM
Thank you all for the help. I think it's going to the shop. I want the hull checked out and want to make sure everything is alright. Just hope it doesn't take them forever...

I don't see any signs of damage in the hull, I believe, like others here, that something else has to be bent. I will try and snap some pics before I take it in, just to join the "What not to do" group... LOL

Thank you all again for the help!