vibration

[special k]

while underway at 15k i suddenly developed a severe vibration yesterday. now cannot exceed 2000rpm in gear without the shake.

i suspect i have something fouled in my prop or shaft, could not free it with reverse thrusts. seems ok at very low speed.

i will get in the water and take a look sunday, hoping to find some rope or debris fouled in my gear, but i have a fear of what my problem is if i find nothing.

can the shaft bearings suddenly fail? i will also look closer to the transmission coupler.

any thoughts?

[jleonard]

I haver located the source of vibration in the past by using a "rocks" glass half full of water. Not a plastic tumbler but real glass.
Place the glass on the suspect part or area. If the vibration is there the water in the glass will tell you.
I have seen the glass jump...then you know where the problem is.

Try it.

[westrivertrawler]

A couple years ago, I had my prop tuned during spring commissioning. During the trip from the boatyard, developed a severe vibration; blamed the prop tech. He went out with my mechanic and me and used the "bucket half full of water placed on the deck right over the prop" test. Not a ripple! Further investigation showed the engine was vibrating so bad it seemed it would jump it's mounts. The long and short of it was that there were several bad injectors, so we had them all rebuilt. Been running smooth ever since (knock on wood!!).
Good Luck!

[special k]

went to the boat yesterday intending to find the vibration source. while inspecting the coupler from tranny to shaft i found two of the four bolts had sheared and the remaining two were loose. had to jimmy out the remains of one bolt that also had began gouging some of the aluminum tranny housing.
thinking back there had recently been a slight clunk when shifting into gear but not alarming.

a quick trip to the mystic NAPA for new bolts and an hour more to install them and we were good to go! plans are now back on for the holiday at block island.

checking the coupler bolts for looseness will now be on my regular check and maintanance list.

[jleonard]

Do you use lock washers? (I hope you do) Also I usually use a good grade of bolt/nut. (Not stainless as it is not as strong).
See you at the Block perhaps. I plan on going over Friday am.

[special k]

we'll be anchored in the northeast quadrant of the salt pond, wed thru monday, blue 28te.

cheers!.....mick

[RobS]

Hardened Bolts & Lock Washers...

[Denis]

I'm glad you were able to find the source of your vibration, I hope you found the cure also. I noticed that you were in the Mystic area, I keep my boat in Mystic, where are you located?

[special k]

i'm currently at mystic point, formerly browers cove. i was first advised of the coupler when i was searching for my 28. a member from here was selling hideaweigh, a beauty, when he told me of his incident regarding bolt shear at the coupling.

unfortunately we couldn't come to terms, but apparently this item should be a regular check. E Z access.

hail me up if you see me, blue hull with no transom lettering yet.....special k