Prop Issue - Minor or Major?

E

Eric K

New Member
Oct 30, 2013
14
Southern Calif
Boat Info
2005 Sea Ray 420 Sedan Bridge
Engines
Cummins 480CE
On my 2005 420 DB, I have 26”, four blade props. On the starboard side, two blades (side-by-side) are out of track by 3/16”. I’m not sure which blades are pushed forward or aft. And, not sure if the pitch or balance has been affected. There are no nicks or chips in the props. The ship yard guys say that it is a minor issue and the local prop shop says it’s a big deal and could create vibration. The boat has a minor vibration all the time and at certain rpms more of a slight shake. I think it is an issue, but my maintenance guys tell me it is within normal tolerances for a power boat. The vibration does seem less with full tanks vs. empty tanks. Any input on the prop deviation would be appreciated.
Thanks.
 
You shouldn't have any vibration from the props. This can cause your cutlass bearings to wear prematurely. I imagine it will also fatigue your shaft over time.
 
It is an issue because vibrations don't get better, they get worse over time and start to shake the boat apart. The prop repair guy is saying it's a bad thing because he wants your business.

I had the props on my 330 run through the PropScan system. I couldn't believe how vibration-free the boat became after that, and the shop that did it said the were not far out of tolerance.

Do yourself a favor and pull the props and have them balanced by a GOOD prop shop. Ask around to find out who others have been happy with.
 
Sea Ray props are much more highly engineered than that. Two blades out by 3/16ths' is going to cause a shake that will wear the bearings and make the boat very uncomfortable for passengers, not to mention the lost efficiency on the prop with bent blades.

Get a diver and have the props removed and taken to a prop shop to be straightened and balanced…….it will be the best $700 you ever spend.
 
Eric K said:
... and the local prop shop says it’s a big deal and could create vibration. The boat has a minor vibration all the time and at certain rpms more of a slight shake. ....
Click to expand...

It sounds like you've answered your own question. Listen to the prop guy, that's what they do for a living. My prop guy tells me not to allow the yard to place a wood on the tip of the blades when installing the props, b/c they could slightly mess up the perfectly balanced prop.

No question, follow Frank's advice.

Short haul might make sense, in case if you want/need any other work done, like zincs, bottom job, etc.
 
Thanks everyone for the advice. I was leaning toward having the props checked/serviced, but it's nice to get confirmation at least as a place to start. And, while I'm at it the port rudder post needs new packing, so I will schedule the haul out.
Thanks again.
 
Alex F said:
My prop guy tells me not to allow the yard to place a wood on the tip of the blades when installing the props, b/c they could slightly mess up the perfectly balanced prop.
Click to expand...

Then how do you hold the props when tightening/loosening the prop nut? I've always used a block of wood ...
 
Use a big pipe wrench on the shaft to hold it.
 
fwebster said:
Sea Ray props are much more highly engineered than that.
Click to expand...
Although not manufactured by Sea Ray. The tolerances allowed by spec at time of manufacture, is much tighter than the 3/16 that you are off. They MUST be run through an MRI scan and put back to spec at a qualified prop shop. Or you will cause more costly damages to your running gear.
 
Last edited:
Turtlesboat said:
Use a big pipe wrench on the shaft to hold it.
Click to expand...

What Mike said.

When the props come off it's ok to use the wood, but when the props comeback from the shop, no wood, just the big pipe wrench.

Mike, do you use anything to protect the shaft from getting scratched? I've tried some rubber and plastic but it makes the wrench slip. So, it ends up being the teeth of the wrench on the bare metal of the shaft. I'd love to find some good way to protect the shaft.
 
Alex F said:
What Mike said.

When the props come off it's ok to use the wood, but when the props comeback from the shop, no wood, just the big pipe wrench.

Mike, do you use anything to protect the shaft from getting scratched? I've tried some rubber and plastic but it makes the wrench slip. So, it ends up being the teeth of the wrench on the bare metal of the shaft. I'd love to find some good way to protect the shaft.
Click to expand...
Ridgid Tool makes some real heavy duty strap wrenches....or....you could buy a split ring collar, put it on the shaft and wrench on that.
 
I've never had the wrench dig into the shaft. my shafts are covered in zinc coat so there's a little protection against a surface scratch.
 
Or you could do it the old school way…..slide a 2x4 between the blades, position it at the hub near the root of the blade and block the prop between the strut and the rudder…not by jamming the block between the blade and the bottom of the hull.
 
I have shaft zincs on my boat, so I clamp the pipe wrench to the shaft zincs, do my prop work in the spring, then change the zincs before launch. No shaft marring at all....

Dale
 
Turtlesboat said:
Use a big pipe wrench on the shaft to hold it.
Click to expand...

I should have clarified that I have Bravo III outdrives ... I can see the pipe wrench working on V drives. I've always used wood on the outdrives, just wondering if there was a better way ...
 
A wood block between the props under the anti ventilation plate is the recommended practice. Having the right sized sockets is necessary as well as the nuts are bronze and water pump pliers will tear them to pieces.

Henry


Sent from my iPad using Tapatalk HD
 
2014-02-19 14.09.29.jpg

Props fresh out of the shop....
 
Prop update: Decided to have the props pulled with the boat in the water. I found a local diver who specializes in prop removal with an adapted underwater hydraulic system and then sent them to Wilmington Prop Service. Wilmington confirmed that two blades on the starboard prop were out of track but the bigger issue was that the prop was out of balance by 800 grams (1.75 lbs). They said no more than 60 grams is acceptable. I’m not sure how a prop gets that far out of balance, but I’m glad to get it fixed. So, the props were repaired, balanced, polished and reinstalled last Tuesday and I was hoping to test them out this weekend. Unfortunately, So. Cal. is experiencing a heavy rain storm at the moment. And, even if it clears a bit tomorrow, I’m afraid I might run over something floating in the LA harbor. The Los Angeles River empties into the harbor just North of the marina. I think that was my mistake last November when I took her out the day after a reasonable rain storm and got something wrapped around the prop just long enough to pull two blades out of track. :smt021 I have heard that small cars and car parts have been known to float down the LA river. I can imagine what else might be floating in that mess. So, I better play it safe and wait another week to test them out and see if the vibration is gone.:smt018
 
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