Cruisers Forum
 


Join CruisersForum Today

Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 13-12-2018, 19:19   #16
Registered User

Join Date: Jan 2006
Location: Rhode Island
Boat: Tayana FD-12
Posts: 736
Images: 6
Re: Feathered Prop Question

Quote:
Originally Posted by boatpoker View Post
I am Certified Corrosion Analyst.

That is stray current corrosion.
99.99% of the time that stray current is coming from the vessel itself.

I'd bet that the prop and strut are manganese bronze which is roughly 35-38% zinc. To call this bronze is actually a misnomer as is metallurgical circles the high zinc content places it squarely in the "brass" class.

You cannot repair that by welding. Corrosion to that extent is deep within and throughout the metal. In fact the corrosion will be much more on the inside than what you can see on the outside. To demonstrate this I have attached an X-ray of a single pinprick size hole on a stainless steel shaft. The shaft photo clearly shows it was much worse under the surface.

You need a qualified electrician to track down the issue.

PS. No qualified person will use the term "electrolysis" so if he uses that term, find someone else.
That's a pretty good photo of what often happens. What I would do is use either dremmel or angle grinder to dig out the craters and see if it is indeed worse beneath the surface. More often than not it is. I had what appeared to be a hairline cracked on one of my chain plates and tried digging it out. To my surprise it got bigger and bigger beneath the surface. I ended up throwing it away.
__________________

phorvati is offline   Reply With Quote
Old 15-12-2018, 19:56   #17
Registered User

Join Date: Jan 2015
Location: Sequim, WA
Posts: 267
Re: Feathered Prop Question

Quote:
Originally Posted by phorvati View Post
That's a pretty good photo of what often happens. What I would do is use either dremmel or angle grinder to dig out the craters and see if it is indeed worse beneath the surface. More often than not it is. I had what appeared to be a hairline cracked on one of my chain plates and tried digging it out. To my surprise it got bigger and bigger beneath the surface. I ended up throwing it away.
Too easy to screw up the balance. For $1600, I'll have PYI rebuild it with new blades and give it a full service.
__________________

CptCrunchie is online now   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Our Feathered Friends' Droppings niel12 Liveaboard's Forum 43 18-07-2011 14:19
Prop Zinc Is Gone and Now I Have White Spots on the Prop dubhouse Propellers & Drive Systems 21 01-12-2010 13:59
Our Feathered Friends bvimatelot Off Topic Forum 15 29-05-2010 17:28
Feathered Prop? Cyrus Safdari Propellers & Drive Systems 5 22-07-2009 07:38
Vari-prop vs. Max-prop winds aloft Product or Service Reviews & Evaluations 21 30-07-2008 10:22



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 19:41.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.