Rudder cracked

[timjet]

I had to remove both my rudders to replace the rudder logs which were leaking. It's difficult and perhaps impossible to replace the packing material in the log due to it's location. Upon cleaning the stbd rudder I noticed the cracks, shown clearly in the attached pictures. There are 2 cracks, one on either side of the housing.

<ul>[*]Anyone know how this could have possibly happened?[*]Can this be fixed?[*]Where do I get it fixed or replaced?[/list]

-- Edited by timjet on Saturday 18th of December 2010 01:15:56 PM

-- Edited by timjet on Saturday 18th of December 2010 01:17:09 PM

 

[sunchaser]

There are many fixes that will come your way on this timejet. The first thing I'd do is get the advice, replace*and/or repair cost from of the nearest GOOD boat shop who does prop, shaft and rudder repairs.

It is tough to tell from the photo how the shaft (SS?) is pressed or held into the rudder (bronze?). Assuming the shaft and rudder are not "dissimilar and causing emf issues, how I would do it:
--Pull shaft from rudder
--Cut out cracked portion
--Weld/buildup with bronze a new shaft insert area
--Drill the new buildup area*to accept shaft

But it may be cheaper or better to get new rudders and shafts

 

[Marin]

Tom--- Just curious because I know next to nothing about metal fabrication. But would a possible solution be to drill a little "stop hole" or "stress relief hole" at the end of the crack to prevent it from propagating farther and then weld over the crack?

-- Edited by Marin on Saturday 18th of December 2010 02:28:08 PM

 

[timjet]

Thanks Tom.

The shafts are SS and the rudder bronze. It appears the crack goes completly through the bronze on one side but not the other. Didn't think about a prop shop but I just left my props at General Prop in Bradenton FL 4 days ago jso will take the rudder in when I pick up the props. I'll let you know what they say.

 

[sunchaser]

Yes Marin, that could be done, but in my opinion may not address the potential underlying issues. Another concern I'd have is the*different metals will expand*unevenly as welding occurs, so breaking the whole thing apart may have merit.*But the problem may have resulted initially from improper boring of the rudder for the shaft diameter, faulty design, Carver grabbing the wrong rudder from the shelf*or not enough meat on the rudder itself. Or maybe grounding caused the failure.

 

[FF]

My guess would be the boat was backed into an object.

A prop shop will fix it easily.

 

[Doc]

How about an expanding shaft as a result of crevice corrosion or some other evil? My buddy's Carver lost both prop shafts to CC and the shop said that the SS shaft metal was of an inferior grade.

 

[Phil Fill]

Being cheap I would take it to the shop that does the work for the prop shop.* If you where in the Seattle area, the plant could probable repair or at least recommend a place.* We mfg pulp/paper/sawmill equipment and get into all kinds of metal. *The rating of SS and Bronze, is close*so welding repair should be OK.**If you have some quetions*I could ask th shop, so you sound some what knowldgable to keep them on there toes.***

*

The shop loves it when I come in carrying an odd looking boat part and/or my hand scribbled drawings.**Another of Phil's R/D*projects.*

***


-- Edited by Phil Fill on Sunday 19th of December 2010 09:30:06 AM

-- Edited by Phil Fill on Sunday 19th of December 2010 06:14:07 PM

 

[timjet]

Thanks guys, I'll post what the prop shop says, probably next week.

I'm looking forward to hearing their opinion as to what caused this. The pictures don't show it but there is some pitting on the SS shaft where it went through the rudder log. More on this one than the other rudder. I'll also bring that to the attention of the prop shop.

 

[Doc]

The pitting is CC.

 

[Woodsong]

keep us posted- I am curious what they suspect might have caused it...Doc sounds like he might be on to something though.

 

[jleonard]

You might also consider adding a cross pin to hold both together as an extra insurance.

 

[RickB]

"You might also consider adding a cross pin ..."

While that might seem like a good idea at first, that could create more problems that it might solve.

A good welding shop (which might also be part of that good prop shop)*can gouge out the crack down and into the post material and weld the assembly together.

While they are taking care of the cracks they can fill those corrosion pits and straighten the post before returning it.

They might also find it cheaper to use an old aquamet shaft to make a couple of new posts with SS blade rudders.

 

[Phil Fill]

Doc, what is CC?*

 

[RT Firefly]

Crevice corrosion
Chris Craft
Canadian Club (rye whiskey)
Culture Club (Boy George)......

 

[RickB]

Country Club
Cubic Centimeter
Crash Course
Chris Cringle (KK's American cousin)
Community College
Course Correction
Coffee Can
Crash Cap
Common Cause
Creative Commons
Coca Cola
Credit Card

Oh curse you RTF for starting this ...

 

[Doc]

Maybe CC does stand for coffee can. That's about the same quality of material that the shop told my buddy that his shafts were on his Carver when it suffered from CC.

 

[sunchaser]

My grand kids are coming in a few days so it will definitely be a Calamitous Christmas filled with Clam Chowder, Crunchy Candy*and*Carmel Corn for treats and Cockapoo Crap to Clean Continually.

Common Curse you RT, where will this lead?

 

[RickB]

Could create continuous contributions that consistently corrupt the content of*complementary communications!

 

[Phil Fill]

Timjet, what is the prognoses/status? **

 

[timjet]

Phil Fill wrote:

*
Timjet, what is the prognoses/status?

*

With the holidays and work I haven't gotten the rudder to the prop shop yet. I called them yesterday and found out they are closed until Jan 3. I've got one maybe two weekends in January to work on the boat which includes filling about 150 blisters, installing two rudder logs, two thru hulls, installing a GPS sensor, and painting the bottom. I also gotta get 3 rusted bolts off the exhaust side of the stbd turbo. The bolts will probably have to be drilled out.*
I think I need some help!!!

*

 

[timjet]

I took the rudder in to Admiral Prop in Tampa today. After conferring with their machinist he gave me an estimate to repair the crack. They will remove the SS shaft and replace with a new one that is in my understanding encased in bronze. The will cut out the old shaft and weld in the new assembly. The SS shaft must be replaced because there is pitting at the point where the shaft goes through the rudder log, and this is why I was leaking so much water. The pitting is too severe to repair.

My quandary: Repair is $325, new is $535. The prop shop says their repair is good as new. I called my mechanic to get his opinion and he said replace with new because you don't know the condition of the bronze inside where the shaft sits.

I'm waiting to hear from the manufacturer of the rudder who is still in business and where I will get the replacement, Marine Associates in WI.

What do you guys think, repair or replace?

 

[Doc]

Did they say what caused the problem? If it was made of cheap material, I wouldn't replace from the same company.

If I knew that I was getting a quality replacement I would do that.

 

[RickB]

timjet wrote:What do you guys think, repair or replace?

The idea that they are willing to machine the shaft out of the rudder and insert a replacement yet*they claim they can't repair the*pitting*makes me a bit nervous.

I'd go for a second opinion at a welding/machine shop that does industrial repairs of pumps and mill machinery. Look for one that does flame spraying buildup for shaft repairs.



*

 

[jleonard]

"Repair is $325, new is $535"

Close call assuming the repair really is as good as new and the new material is as good as the old.

Generally speaking if the repair is more than half the cost of new go new. This is close.

 

[timjet]

Doc wrote:

Did they say what caused the problem? If it was made of cheap material, I wouldn't replace from the same company.

If I knew that I was getting a quality replacement I would do that.

The prop shop did not offer an explanation as to why it cracked nor did they express an opinion of it's quality. My opinion: It cracked because the PO hit something in the water at high speed, though nothing else shows any damage, or he ran aground. The prop shop has given me the option of repairing or replacing with the opinion that the repair will be good as new.*

*

 

[timjet]

RickB wrote:

*

The idea that they are willing to machine the shaft out of the rudder and insert a replacement yet*they claim they can't repair the*pitting*makes me a bit nervous.

I'd go for a second opinion at a welding/machine shop that does industrial repairs of pumps and mill machinery. Look for one that does flame spraying buildup for shaft repairs.

I don't remember the machinist exact words but he indicated that the cost to repair the pitting on such a small shaft would exceed the cost to replace it.*The opinion of the machinist was that the pitting was caused by*electrolysis due to poor grounding of the bonding system. The pitting only*occurred at the point where the shaft comes in contact with the packing material in the rudder log about 1 inch in length and the circumference of the shaft.*He didn't say he couldn't repair the pitting just that it would cost more than to replace it.*

*

 

[timjet]

jleonard wrote:

"Repair is $325, new is $535"

Close call assuming the repair really is as good as new and the new material is as good as the old.

Generally speaking if the repair is more than half the cost of new go new. This is close.

Yes this is a close call, but I think replacing is the right call. If the repair is not done correctly and the prop shop stands behind their work, I doubt they will pay to have the boat hauled in which case any money saved would be absorbed in the haul out fee.*

I like your last comment and will probably use that formula in the future.*

*

 

[Woodsong]

$200 more and you get a brand new one? For me it would be no debate- brand new replacement would be on order! $200 is cheap peace of mind for not having to worry about it again down the road, particularly if you are far from home. $200, in boat dollars, is like only $10 extra for land based stuff! Go for the new one is my vote and keep the old one at your house "just in case" you ever need it for some strange reason.

 

[timjet]

Woodsong wrote:

$200 more and you get a brand new one? For me it would be no debate- brand new replacement would be on order! $200 is cheap peace of mind for not having to worry about it again down the road, particularly if you are far from home. $200, in boat dollars, is like only $10 extra for land based stuff! Go for the new one is my vote and keep the old one at your house "just in case" you ever need it for some strange reason.

Yup, I'm gonna order a new one tomorrow.

Thanks everyone for your help.

*