Vibration at WOT

[Rickysa]

New shafts about a year ago, had a diver under the boat last week to clean, first time we have had this happen...vibration at WOT. Back it down a bit and the vibration goes away.

Haven't hit anything either...

Suggestions welcome.

Rick
'85 45C

[Passages]

Was the problem there before the diver cleaned Props & Shafts?

Fishing line chew up the Cutlass Bearing?

Engine Alignment OK?

Last resort - don't go WOT...

[Trojan]

What engines are you running and how is your speed? Do you get the same speed and RPM as before the vibes? Was the vibes there before the cleaning? Need a little more info.

BILL

[Rickysa]

nope, problem not there before the cleaning, and the boat hasn't been out to get anything around the shaft, and can't imagine anything that would have thrown the alignment off???

Thanks for the response!

New Capt on board trying to get a feel for the boat and pushed it to WOT...just curious why it would only show up there.

Rick

[MikeP]

Are the engines in synch at WOT? A synchronizer will disconnect at WOT if the engines aren't properly set up for the synchronizer ( the slave engine governor must be set for a higher WOT RPM limit than the lead engine).

If the engs are not in synch either because the synchronizer disconnected OR if doing it manually, you don't have the engines at the same RPM - you may get a vibration that is NOT a result of an actual out of balance condition at all, but just from the harmonic of the two engines beating against each other.

[Rickysa]

6V92s....we have been having issues with boat speed and WOT rpm not hitting 2350 (maybe 50-100 off) before the vibration was noted this past weekend.

Phototach shows our stb. engine guage to be 100 rpm off from 2000 and up, and to be honest, I'm not sure where the Glendenning sync. gets its info from...the tachs on the bridge are even, but the engines aren't...I'm not sure if the sync was on when they felt the vibration...they just backed her down and left it there.

Thanks again for the input,

Rick

[Mike36c]

Maybe the diver left one prop blade with some growth, a dinged blade, small rope tangled? Hate to say it but its time to get wet and have a peek, then go from there.

[Rickysa]

Maybe the diver left one prop blade with some growth, a dinged blade, small rope tangled? Hate to say it but its time to get wet and have a peek, then go from there.

Mike, that is the plan...I've not been around the boat through all of this, but I'm thinking the diver didn't do much of a job on the running gear...we had something painted on the running gear of our old Bertram that worked miracles, but I think it's been banned by the EPA nowadays...bummer

Rick

[Mike36c]

Mike, that is the plan...I've not been around the boat through all of this, but I'm thinking the diver didn't do much of a job on the running gear...we had something painted on the running gear of our old Bertram that worked miracles, but I think it's been banned by the EPA nowadays...bummer

Rick

I'm have four months on my first application of propspeed applied to my running gear, so far its working nicely but still too early for conclusions. I need to change shaft zincs next time I see the boat, I'll forward a current report.
Mike

[Genesis]

Sounds like you got some stuff on one of the blades of the wheels or a half-azz job done cleaning..... time to do a bit of diving.