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Catalina/Capri 25/250 Sailor's Forums

Catalina 250 Specific Forum

Electrolisis in my keel

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Barcalon
Deckhand

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Chile
6 Posts

Initially Posted - 12/08/2009 : 06:19:45

I have a Catalina 250 swing keel.
The steel cable that pull the keel is eroded avery couple of months. I leave the boat in the water all season, but last season it cut it twice. Now I replaced by a very strong rope. My concern is that the electrolisis will keep going by some other place.
Hoy can I prevent this corrosion? Zinc anode? Where?
Thanks

Edited by - on

ruachwrights
Captain

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USA
258 Posts

Response Posted - 12/08/2009 : 09:15:57

I wasn't aware that the Catalina 250 ever made a swing keel? I think you may need to post this question of the Catalina 25 Forum.

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John Russell
Master Marine Consultant

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USA
3444 Posts

Response Posted - 12/08/2009 : 10:24:26

It's only technically a keel since it extends below the boat at the midline. Since it doesn't really provide ballast, it is really simply a centerboard that provides resistance to lateral motion (leeway).

But, that's not the real question. I'm only guessing here but since this hasn't been widely reported, it probably hasn't been a problem since most of the centerboard models are not left in the water all the time. They're often the of choice for their users because of the ease of trailering and, I think, most folks with that version store them on their trailers and not on a mooring. I think you're right about the electrolysis continuing, Barcalon, but I can't think of a place to attach a zinc to other than the centerboard. I assume you have an outboard motor that you pull up when not in use.

A propósito, recepción al foro.

Edited by - on

JohnMD
Navigator

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USA
207 Posts

Response Posted - 12/08/2009 : 11:59:52

The stainless cable that WAS used on the WB 250's has been replaced with a piece of lexan (I think) rope. I have a '95 and Catalina sent me a free kit to replace the cable. I have and haven't had any problems.

Since we don't have an inboard motor, there's really not much made out of metal that stays in the water (I assume your outboard gets pulled up). Only thing on my boat is the keel pin and I've never seen any erosion on that. I would think the cable will be your only issue.

Edited by - JohnMD on 12/08/2009 12:04:26

Dave Bristle
Master Marine Consultant

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Djibouti
10005 Posts

Response Posted - 12/08/2009 : 12:45:00

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by JohnMD
 ...replaced with a piece of lexan (I think) rope.<hr height="1" noshade id="quote"></blockquote id="quote">Close--Vectran. Try Catalina... Also, Catalina Direct has a [url="http://www.catalinadirect.com/index.cfm?fuseaction=product.display&Product_ID=1572"]kit[/url] including the hardware and the rope.

Edited by - on

528
Navigator

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USA
181 Posts

Response Posted - 12/08/2009 : 15:16:02

Contact Catalina in California. They were shipping the kit for free a few years ago.(it includes the vectran and an appropriate block) Mine has been working flawlessly for 5 years.

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John Russell
Master Marine Consultant

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USA
3444 Posts

Response Posted - 12/08/2009 : 17:14:52

I doubt they're shipping for free to Chile.

BTW, Barcalon, is yours the boat we've seen on youtube with a stainless steel arch over the transom? If memory serves me correctly, it was in Chile.

Edited by - on

Dave Bristle
Master Marine Consultant

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Djibouti
10005 Posts

Response Posted - 12/08/2009 : 19:10:53

Problem solved... BTW, zincs only work if they're electrically connected to the metal you want to protect, and also in contact with the water. Attaching one to a fiberglass centerboard won't protect anything.

Edited by - Dave Bristle on 12/08/2009 19:17:32

Barcalon
Deckhand

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Chile
6 Posts

Response Posted - 12/09/2009 : 09:13:20

Thanks everybody for the quick response.
My Catalina is a 250WB 2001 and as John said it has a centerboard, not really a keel, but for some reason is called swing keel. I replace the stainless cable for a "Endura" New England rope, that supports 2,200 lbs in 3/16 inches.
Dave comment regarding the zinc make all the sence, so I will see what happen after the season, which by the way is just starting....
John, my boat does not have the stainless arc on the transom, there are many sailing by this latitudes.
Thanks again for the comments and help.

Edited by - on

DaveR
Master Marine Consultant

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USA
2015 Posts

Response Posted - 12/09/2009 : 13:13:20

From what I understand, not only can an electrical problem on your boat cause a quick demise to your zinc, anyone anywhere close to you with an electrical problem will cause the same deterioration in the zinc, making it go away in months instead of years. Is this true?

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John Russell
Master Marine Consultant

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USA
3444 Posts

Response Posted - 12/09/2009 : 14:11:58

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by DaveR
 From what I understand, not only can an electrical problem on your boat cause a quick demise to your zinc, anyone anywhere close to you with an electrical problem will cause the same deterioration in the zinc, making it go away in months instead of years. Is this true?
<hr height="1" noshade id="quote"></blockquote id="quote">Yes.

That's why many marinas disallow swimming in the marina. Lots of leaky boats, electrically speaking.

Edited by - on

GaryB
Master Marine Consultant

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USA
4304 Posts

Response Posted - 12/10/2009 : 19:36:09

It could likely be electrical wiring in the marina that is hanging down in the water and leaking current into the water.

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zeil
Master Marine Consultant

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Canada
1314 Posts

Response Posted - 12/11/2009 : 20:55:24

Please help me understand... for electrolysis to have an effect on metal keel parts below the water surface would they not have to be tied in with the boat's electrical system. Our C250 WB centerboards are hinged and mounted using metal parts connected to a metal cable using metal fasteners along with a metal turning ball to the 5:1 up-haul non metal system but NOT connected to anything else...

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Dave Bristle
Master Marine Consultant

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Djibouti
10005 Posts

Response Posted - 12/11/2009 : 22:23:11

Henk: Any metal below the surface is subject to electrolysis from stray current in the water--typically from nearby boats with electrical leakage in the engine/propeller shaft system, or from aged electrical shore power cables under marina docks. A sacrificial zinc anode "takes the hit" for any less active metal it's "electrically" connected to (usually by being bolted to it). In a marina, you should expect some stray juice. The Vectran cable for the C-250-WB is good insurance. If there's any other metal in the water when you're in a marina, it's at risk without some zinc protection.

Edited by - on

sailorman
1st Mate

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USA
69 Posts

Response Posted - 12/13/2009 : 18:36:24

There was a comment from John Russell that "most of the centerboard models are not left in the water all the time". My boat a 2004 wb is in the water year round here in Georgia as are at least four other 250-wb that are in the same marina. In addition, I know of several 250-wb in the Florida area that are in the water year round. Now after 5 years I had the steel centerboard line replaced with the vectran line from Catalina. The wear on the steel cable has more to do with the ride over the turning ball and and simple corrosion making it less flexable in use.

Edited by - on

zeil
Master Marine Consultant

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Canada
1314 Posts

Response Posted - 12/16/2009 : 09:41:58

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Any metal below the surface is subject to electrolysis from stray current in the water--typically from nearby boats with electrical leakage in the engine/propeller shaft system, or from aged electrical shore power cables under marina docks. A sacrificial zinc anode "takes the hit" for any less active metal it's "electrically" connected to (usually by being bolted to it). In a marina, you should expect some stray juice. The Vectran cable for the C-250-WB is good insurance. If there's any other metal in the water when you're in a marina, it's at risk without some zinc protection.<hr height="1" noshade id="quote"></blockquote id="quote">

Dave... if that is the case how could one protect the, hard to get to, bronze turning ball and ss bronze turning ball mounting pin when a Vectran, non conductive, cable is used. It seems impossible to add a zinc in that location.

Just in case, several years ago we had a sacrificial zinc added to the centerboard hinge mounting hardware and by using the old style steel up-haul cable the turning ball is supposed to be protected...

BTW the zinc, after 3 years, is somewhat pitted

Edited by - on

Dave Bristle
Master Marine Consultant

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Djibouti
10005 Posts

Response Posted - 12/16/2009 : 13:53:30

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by zeil
 Dave... if that is the case how could one protect the, hard to get to, bronze turning ball and ss bronze turning ball mounting pin...<hr height="1" noshade id="quote"></blockquote id="quote">I don't know the WB configuration well enough to respond, but I think bronze is less affected than stainless steel (which needs oxygen), and therefore much better for most purposes below the waterline. You could ask Catalina--I gather they're using the Vectran cable now.

Edited by - on

zeil
Master Marine Consultant

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Canada
1314 Posts

Response Posted - 12/25/2009 : 14:12:58

Just today took a picture of the zinc attached to the C250 WB centerboard suspension after our return from San Diego...

you bet I'm now a believer of protecting exposed underwater metals... The last marina we were must have been cooking "hot", with stray currents.

The center part of the zinc is still more-less intact due to accidentally coating it with ablative bottom paint.

Now I wonder how one would protect the (brass?) turning ball and (SS?) mounting pin when using a non-conductive Vectran rope like up-haul cable...

No... not bubblegum stuck to the underside of the boat but a self sacrificing zinc screwed to the centerboard suspension.

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Sloop Smitten
Master Marine Consultant

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USA
1181 Posts

Response Posted - 12/26/2009 : 09:29:33

Related to this topic . . .
One of the gentlemen on my dock was putting on his LED Christmas lights when he dropped one end into the water. The cord was plugged in but the switch was off essentially providing a ground for the light string. The string lit up and glowed for several seconds before it went out. Must be some pretty sizable current flowing in that water around the slips.

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Barcalon
Deckhand

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Chile
6 Posts

Response Posted - 12/28/2009 : 05:15:32

Thanks Zeil.
Thanks for the feedback.
I agreed absolutely, with the vectran, we better find some way to release the electrolisis.
When I replaced with the endura rope, I left a couple of inches of the stainless cable, so I hope it act as a zinc anode for the season.
regards

Edited by - on

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