The Captain Reported A Severe Vibration!

[jackieschmidt]

I'm guessing you don't just lift that off with one hand. What diameter is that prop?

That vessel uses a 74 inch diameter X 54 pitch wheel. The engine is a KT -38 Cummins at 1000 HP at 1800 rpm. It goes through a 5.9 to 1 reduction gear, making the shaft speed at around 300 RPM.

 

[jackieschmidt]

Don’t even need the dye check on the 2nd blade.

I’ve never seen a rudder configuration like that, must be an inland thing?

99% of inland and river push boats use a 6 rudder system the rudders aft of the propellers are the main steering rudders. The 4 rudders forward of the propellers are flanking rudders, used in backing up and allowing the captain to actually shift the vessel sideways by skill use of the main rudders and flanking rudders.

Here is a picture of one of the main rudder,, prop, and flanking rudders on a new 3200HP tug that is going into service soon.

The other picture is the vessel when we align bored the shaft line back in July.

 

[jonbearman]

Jackie I will bet you have a million stories of how people butcher these vessels. You should write a book! I am assuming these are river and saltwater vessels you work on.

 

[ELR LVR]

I cant count how many vehicles have came into my shop that we tell customers there are issues and we get blamed for causing the issues since they never noticed it.

I tell my customers
"This is an at your own risk facility, I accept no responsibility for how you treat your machine"
And there are no warranty on China Parts (when they dont wish to pay for OEM)

 

[jackieschmidt]

Jackie I will bet you have a million stories of how people butcher these vessels. You should write a book! I am assuming these are river and saltwater vessels you work on.

Yes, I do.
You would be hard pressed to find a more abused piece of equipment than an Inland Pushboat.
It’s more due to the extreme environment that they work than human fault.

The darned things just seem to be self destructing on a daily basis.

I rather jokingly say that in my Shop, we have a rather simple business plan, “They break it, we fix it, we bill them, they pay us”.

 

[PhilC]

$1600 over idiots and a dry ball joint.

Yeah, I fix my own cars now.

Sorry for the thread drift.

Do my own as well, that way there's only one person to blame if wrong.

 

[ELR LVR]

Yes, I do.
You would be hard pressed to find a more abused piece of equipment than an Inland Pushboat.
It’s more due to the extreme environment that they work than human fault.

The darned things just seem to be self destructing on a daily basis.

I rather jokingly say that in my Shop, we have a rather simple business plan, “They break it, we fix it, we bill them, they pay us”.

When I ran my welding business for some 15 years or so
My main income was repairing Heavy Equipment
Such as Bulldozers D8's, excavators, backhoes etc
They are very tough but not indestructable
Every person that operates one, except for the Owner of one
treats them as if they are indestructable, No finess
When I run equipment I try to finess things like the hydraulics, ease into it, absorb the load like working a human muscle, rather than working it like a ...muscle car ...haha
----
I bet they treat their boats the same way as a big heavy piece of equipment
thinking that since its so big, and heavy it must be indestructable
---
worse yet, is instead of maintaining them to prevent downtime
(Keep nice machines, running nice)
they wait until it's broken before deciding, maybe its time to give it some maintenance
and then try to suggest it's an emergency and can't afford the downtime

 

[ORjeff]

That vessel uses a 74 inch diameter X 54 pitch wheel. The engine is a KT -38 Cummins at 1000 HP at 1800 rpm. It goes through a 5.9 to 1 reduction gear, making the shaft speed at around 300 RPM.

So if I did the math right, 1000 HP at 1800 rpm = 2918 ft-lbs of torque at the crank shaft. *5.9 = 17,216 ft-lbs of torque at the prop. So that's the equivalent of 5739 pounds hanging from the OD of the prop. I'll let someone else ponder what the pressure is on the face of those blades. Seems like the wrong place to go cheap.