Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 04-05-2010, 19:52   #1
Now on the Dark Side: Stink Potter.
 
CSY Man's Avatar

Cruisers Forum Supporter

Join Date: Aug 2003
Location: Ft. Lauderdale
Boat: 2001 Albin 28TE.
Posts: 3,399
Images: 115
If Yer Shaft Zinc Is Gone...?

If your shaft zink died and departed a month or 2 or 3 ago, what would be the damage?

Just a pitted prop, or more serious stuff?

(Moderately active area, not a marina with stray currents.)
__________________

__________________
Life is sexually transmitted
www.odincharters.com
www.susanhanssen.com
CSY Man is offline   Reply With Quote
Old 04-05-2010, 20:36   #2
Senior Cruiser
 
skipmac's Avatar

Cruisers Forum Supporter

Join Date: Oct 2007
Location: 29 49.16 N 82 25.82 W
Boat: Pearson 422
Posts: 12,382
Prop is the most likely problem area. Check for loss of metal usually starting at the tips of the blades. Not visually obvious unless it's really bad. Polish the blades and look for a pinkish color on the blade tips. Also tap with a metal object and listen for a nice ring or a dull sound, changing as you go toward the tip.
__________________

__________________
The water is always bluer on the other side of the ocean.
skipmac is online now   Reply With Quote
Old 05-05-2010, 13:27   #3
Now on the Dark Side: Stink Potter.
 
CSY Man's Avatar

Cruisers Forum Supporter

Join Date: Aug 2003
Location: Ft. Lauderdale
Boat: 2001 Albin 28TE.
Posts: 3,399
Images: 115
Thanks.

Hopefully no damage yet.
Been too lazy to go down and look, but diver said zinks were gone.

Should hang a zink grouper over the zide with a wire to the shaft.
Had an old one laying around..Will look for it.
__________________
Life is sexually transmitted
www.odincharters.com
www.susanhanssen.com
CSY Man is offline   Reply With Quote
Old 05-05-2010, 13:43   #4
Registered User

Join Date: Mar 2008
Posts: 84
The bronze prop strut on my 1981 Hunter 30 broke twice, most likely due to electrolysis. The first time I had it repaired. The second time I was forced to have a new one cast. As far as I know, the prop is the original one and still looks as good as new.

I doubt if your boat suffered any serious damage if you had no zincs for a short period of time. You'd be smart to replace them when you get a chance.
__________________
Alan Brown is offline   Reply With Quote
Old 05-05-2010, 13:57   #5
Don't ask if you can't handle it
 
sailorboy1's Avatar

Cruisers Forum Supporter

Join Date: Jul 2007
Location: On the boat somewhere
Boat: Hunter 410
Posts: 12,317
if you have zincs in your engine heat exchanger, it's time to check them!
__________________
sailorboy1 is offline   Reply With Quote
Old 05-05-2010, 15:38   #6
Registered User
 
Hydra's Avatar

Join Date: May 2009
Location: Lorient, Brittany, France
Boat: Gib'Sea 302, 30' - Hydra
Posts: 1,229
It might be useful to have more than one zinc in the water. I have three: one on the propeller hub, one on the shaft forward of the strut and a big one on the hull, connected to the engine by a wire. Then, if the zinc on the propeller comes undone from vibrations, the others are still in place.

It's possible to put new zincs by snorkeling. I already dit it twice. For the one on the propeller, it's easy: you just have to hold the zinc, the screw and the wrench. It's more difficult for the zinc on the shaft: it's in two parts and there are two screws and two nuts. The first time I tried, one half of the zinc sunk. Now, I tie safety lines to the zincs and the wrench!

Alain
__________________
Hydra is offline   Reply With Quote
Old 05-05-2010, 17:46   #7
Senior Cruiser
 
Blue Stocking's Avatar

Cruisers Forum Supporter

Join Date: Dec 2008
Location: St. Georges, Bda
Boat: Rhodes Reliant 41ft
Posts: 4,117
Be careful grabbing metal parts under water, and definitely not in marinas.
Make sure no AC is powered up.
A 1/2 volt DC can cause diaphram spasm and drown you.
Not a doctor, but have seen some strange things in marinas.
__________________
so many projects--so little time !!
Blue Stocking is offline   Reply With Quote
Old 06-05-2010, 14:23   #8
Registered User
 
Hydra's Avatar

Join Date: May 2009
Location: Lorient, Brittany, France
Boat: Gib'Sea 302, 30' - Hydra
Posts: 1,229
Blue Stocking,
I already avoid diving in marinas, for other reasons that electricity. I retain your suggestion of disconnecting DC power when diving.

Alain
__________________
Hydra is offline   Reply With Quote
Old 06-05-2010, 15:29   #9
Registered User
 
sailvayu's Avatar

Join Date: Mar 2006
Location: Fort Myers FL
Boat: Irwin 40
Posts: 878
Just hanging a zinc over the side is useless unless it has a low resistance electrical connection to the metal it is protecting even then the distance from the protected metal could effect its usefulness.

Fair Winds
__________________
Capt. Wayne Canning, AMS
www.projectboat.info
http://sailvayu.com/
sailvayu is offline   Reply With Quote
Old 06-05-2010, 16:22   #10
Now on the Dark Side: Stink Potter.
 
CSY Man's Avatar

Cruisers Forum Supporter

Join Date: Aug 2003
Location: Ft. Lauderdale
Boat: 2001 Albin 28TE.
Posts: 3,399
Images: 115
Quote:
You'd be smart to replace them when you get a chance.
Did it when the diver found the zink gone..WIll not knowingly let the boat sit unprotected even for one day.

Quote:
Just hanging a zinc over the side is useless unless it has a low resistance electrical connection to the metal it is protecting even then the distance from the protected metal could effect its usefulness.
Yeah, I hook the fish up to the propshaft, otherwise it won't do nothing..
(got that one figured out )

Quote:
if you have zincs in your engine heat exchanger, it's time to check them!
Yup, they are part of my maintenance program, do it once a year, a pencil zink on the heat exchanger and another pencil zink on the raw water system bonded to the engine block.

Thanks for the help and suggestions guys.
The zink issue took me by surprise, I never leave 'em on long enough to fall off and usually check 'em twice a year and replace once a year.
This time the shaft zink was gone, so was the 2 rudder bearing zinks.
Must have been some stray current or something, I don't leave my boat boat plugged in to shore power so I doubt I killed my own zinks.

Guess I will have to check every 3 months now instead of every 6...
__________________
Life is sexually transmitted
www.odincharters.com
www.susanhanssen.com
CSY Man is offline   Reply With Quote
Old 07-05-2010, 22:29   #11
HiZ
Registered User
 
HiZ's Avatar

Join Date: Apr 2010
Location: Oshkosh WI
Boat: Reinell 26' - SeaFlight 12.5 - Switzer 17ss - 62 Cruisers Lapstrake - 17' SeaSprite
Posts: 25
Quote:
Originally Posted by CSY Man View Post
If your shaft zink died and departed a month or 2 or 3 ago, what would be the damage?

Just a pitted prop, or more serious stuff?

(Moderately active area, not a marina with stray currents.)


Metal will constanly exchange electrodes in water.
So, when dissimalar metals are submerged the softer of the two will loose to the harder of the two.
So, this is why anodes are made of soft metal.
They Loose.
Any metal that is down there is subject
So, what ever is now the softest will be the new Anode
__________________
HiZ is offline   Reply With Quote
Old 07-05-2010, 23:22   #12
Now on the Dark Side: Stink Potter.
 
CSY Man's Avatar

Cruisers Forum Supporter

Join Date: Aug 2003
Location: Ft. Lauderdale
Boat: 2001 Albin 28TE.
Posts: 3,399
Images: 115
Quote:
So, what ever is now the softest will be the new Anode
What if you had a SS prop on a SS shaft with SS thru holes/sea cocks.

Same grade on the galvanic scale and no deterioation, or all the metal slowly but surely goes to he!!..? (Still need zinks?)
__________________
Life is sexually transmitted
www.odincharters.com
www.susanhanssen.com
CSY Man is offline   Reply With Quote
Old 07-05-2010, 23:22   #13
Marine Service Provider
 
fstbttms's Avatar

Cruisers Forum Supporter

Join Date: Oct 2006
Location: Under a boat, in a marina, in the San Francisco Bay
Posts: 3,594
Quote:
Originally Posted by HiZ View Post
Metal will constanly exchange electrodes in water.
So, when dissimalar metals are submerged the softer of the two will loose to the harder of the two.
So, this is why anodes are made of soft metal.
They Loose.
Any metal that is down there is subject
So, what ever is now the softest will be the new Anode
Ummm... not quite. Hard or soft has nothing to do with it. Position on the periodic table has everything to do with it. Zinc anodes give up their electrons because they are lower on the periodic table or less "noble" than bronze or steel.
__________________
fstbttms is offline   Reply With Quote
Old 07-05-2010, 23:26   #14
Marine Service Provider
 
fstbttms's Avatar

Cruisers Forum Supporter

Join Date: Oct 2006
Location: Under a boat, in a marina, in the San Francisco Bay
Posts: 3,594
[QUOTE=CSY Man;448726]
Quote:
What if you had a SS prop on a SS shaft with SS thru holes/sea cocks.

Same grade on the galvanic scale and no deterioation, or all the metal slowly but surely goes to he!!..? (Still need zinks?)
Zinc anodes (there is no "k" in zinc, BTW) protect metal parts from other forms of corrosion besides galvanic. Bottom line- you need to have them.
__________________
fstbttms is offline   Reply With Quote
Old 08-05-2010, 00:02   #15
Senior Cruiser

Cruisers Forum Supporter

Join Date: Dec 2006
Location: Seattle
Boat: Cal 40
Posts: 2,401
Images: 7
Quote:
Originally Posted by fstbttms View Post
Ummm... not quite. Hard or soft has nothing to do with it. Position on the periodic table has everything to do with it. Zinc anodes give up their electrons because they are lower on the periodic table or less "noble" than bronze or steel.
Almost, it's the galvanic table, not the periodic table, and if you look at the order of the galvanic table it doesn't relate to the periodic table in any easy to see correlation. I believe it's fairly complex, I don't remember coming across it in chemistry other than as a list.

Galvanic Series

John
__________________

__________________
cal40john is offline   Reply With Quote
Reply

Thread Tools
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
flexible shaft coupling for short shaft melemakani Propellers & Drive Systems 6 22-12-2015 06:16
Minimum Distance Between Cutlass Bearing and Shaft Zinc Han Engines and Propulsion Systems 13 13-07-2014 19:12
Strut, Shaft, Shaft Log, Engine Alignment KestrelBuck Engines and Propulsion Systems 24 04-04-2011 00:14
Where to Put Zinc on Prop Shaft? b-rad Propellers & Drive Systems 11 29-10-2009 23:01
YouTube video on shaft packing 5 " shaft Roy M Propellers & Drive Systems 5 24-07-2008 10:07



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 02:49.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.