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panamawake
07-10-2009, 05:18 PM
I hit a tree trunk in the ocean a couple days ago, and now when i put the boat in gear out of the water it sounds like something out of titanic. Im sure the prop is bent, but i cant tell if the shaft is as well. How can i check this? Could it be just the fact that i took it out in salt water ?

TMCNo1
07-10-2009, 05:23 PM
I hit a tree trunk in the ocean a couple days ago, and now when i put the boat in gear out of the water it sounds like something out of titanic. Im sure the prop is bent, but i cant tell if the shaft is as well. How can i check this? Could it be just the fact that i took it out in salt water ?


You don't want to run the boat in gear out of the water, it is the water that lubes it and it will make a terrible noise if you do so.

bigmac
07-10-2009, 05:24 PM
Spinning the shaft out of water virtually always makes that noise - no water to lubricate the strut bearing. That by itself doesn't imply any damage. The more you run it without water, the more likely you are to damage the strut bearing from heat and subsequent glazing.

Only way to assure the shaft isn't bent is to put a runout gauge on it, but you can get a good idea by just laying a metal straightedge along it.

Damage to the prop can also imply damage to the strut as well as the shaft.

Hollywood
07-10-2009, 05:28 PM
as well as the transmission

panamawake
07-11-2009, 01:14 AM
how can i get the shaft out to analyze it? is it complicated?

Hoosier Bob
07-11-2009, 09:18 AM
You should be able to tell pretty quickly with a dial gauge mounted to the rudder and turning it by hand. Snapon as well as other companies make some nice ones with various mounts for brake calipers. If it spins and does not appear to mive the gauge then look at your prop. Out of water they sound like all heck is coming loose! Take care!how can i get the shaft out to analyze it? is it complicated?

Cloaked
07-11-2009, 09:40 AM
Any affixed instrument will work to see if the shaft is damaged or misaligned. Just place something on a stationary point and turn the shaft. Watch the gap between the instrument and the shaft for increase or decrease. The dial indicator will tell you how much it is out (by reading the dial indicator gauge) but for a simple test to get an idea, anything will work.

As stated, the noise should be expected (our of water), so don't necessarily assume your drive line is messed up without a test. As Louise stated, a straight edge will provide you an initial indication. Just touch a straight edge at different positions on the shaft (running long way or parallel to the shaft).

I wouldn't pull the shaft until you confirm any damage.

bigmac
07-11-2009, 09:52 AM
how can i get the shaft out to analyze it? is it complicated?

Not terribly complicated, but hard enough that I wouldn't do it unless I had significant suspicion that it were bent.

Once you're sure the prop is OK, I'd take the boat out and run it. If there's no vibration at any speed, you're good to go. If you still have vibration, THEN it would be worthwhile to consider pulling the shaft and have the runout checked. As HB said, though, it's probably something you can do on the boat...set up the dial indicator on the mid-point of the shaft and turn the prop by hand. First thing to do is lay a straightedge along it. That may confirm that it's bent and spare you the expense or trouble of a runout gauge.

If it were me, if the shaft passed the on-boat straightedge test and it didn't vibrate after the prop was fixed or replaced, I wouldn't worry about it.