Electrical issue - anodes and the like

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redunculous

redunculous

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May 13, 2011
420
Hunter 40.5 Legend Jupiter
So

I had an ac unit installed about 4 months ago, I went to clean the filter on the raw water intake pump the other day and found that it has large holes in it.

Being relatively new to boats what should be my next steps in figuring out why its deteroriating so fast? (not had chance to check my anodes yet but will do as soon as I can)

Kind Regards

Redunc
 
sailcruiser

sailcruiser

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Sep 6, 2011
435
The anodes are a good first start. I'm in the process of doing the same thing because we see paint deterioration. My first question is everything properly bonded to the common ground? Is your battery charger grounded to common ground? I assume you are connected to shore power? Your club/marina wiring may not be the best. My club has some issues but right now I am trying to sort things out and tease boat vs shore power issues out so a solution can be tailored to clean it up. SC
 
redunculous

redunculous

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May 13, 2011
420
Hunter 40.5 Legend Jupiter
Hi sailcruiser

Thanks for the response

I will have a check through with regards to the common ground (all very new to me this side)

Yes I'm connected to shore power - is there a simple way to test to see if the marina wiring is at fault? I spoke with a guy a few down from me and he doesnt have an issue so I'm leaning towards it being my boat

I replaced the battery charger last month as the previous one was killing the batteries - I just used the existing wiring.

I guess I need to check the common ground which I am assuming is the big bar behind my electrical panel
 
A

AtlanticAl

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Oct 24, 2011
258
Lancer 28 Grand Lake
I once bought a boat, where the owner stressed to me, that before i sail it, i must put an anode of the shaft, as he knew, their was none there. I didnt want to take the boat out of the water to do it, so after meeting some guy in the bar, he agreed to lend me his scuba equipment (because after a few beers, i had told him i was a bit of a scuba diver, not true, never done it before in my life) he turns up the next day, with his gear, i had my own wet suit, and actually managed to do the dive, (first time ever with scuba equipment) and put the anode on, and i put it on really tight, we ran the engine, possibly fifty hours, and after that fifty hours, their was no anode left, nothing, i kind of thought it fell off, as i handnt put it on tight enough, but now i think it disolved off. I think it just went really quick, might last a year if you are sitting in a marina, but i dont think it last long when you are voyaging.
 
redunculous

redunculous

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May 13, 2011
420
Hunter 40.5 Legend Jupiter
Thats an incredibly fazst disolving rate Al

I have dive gear on board so I'll take a look at mine when I get back to the states next month.
 
sailcruiser

sailcruiser

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Sep 6, 2011
435
It's new to me as well. A good book on the topic is the boat owners electrical and mechanical handbook (close I think) by Nigel Calder. It's late and I'm too cold to get up to look.

From what I've read ideally all metal parts above and below the water line should be tied in to this but I'm starting with below the waterline first. And the battery charger should do the same as well. I'm in the process too of installing a new charger. Mine is currently ~25 years old. A galvanic isolator or the transformer I can't bring up out of my sleepiness will isolate you from the common ground or create a whole new field to work from. I have to be real careful since I have an aluminum saildrive. Can you say the most expensive anode ever?!? I'm in fresh water so I use magnesium but the process is the same.

I'm trying to come up with a test for the bonding wire to see if it broke. Probably a 9v battery.
SC
 
redunculous

redunculous

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May 13, 2011
420
Hunter 40.5 Legend Jupiter
Thanks SC

I have looked into an isolator - my dads a retired electrical engineer and is keen on solving this issue for me next time he comes out

I think I'll stand back, let him run his tests, learn as much as I can and go from there.

Will let you know how I get on
 
sailcruiser

sailcruiser

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Sep 6, 2011
435
Please let me know what he does to test things and if it takes special equipment. EEs are a unique group. I have a good multimeter which will hopefully be all i need Other than power. I'm out of the water until Spring. It's currently snowing so obviously no rush. =). I'm going to watch this thread for any pearls of wisdom. Good luck! SC
 
A

alexco38

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Sep 25, 2008
1,096
CS 30 Toronto
The zinc on my boat has been there for 5 years with a Galvanic Isolator. My next door has to replace it every year. He even have edging on the prop face. Not good. We are in fresh water.

I'm an EE
 
Bill Roosa

Bill Roosa

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Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
Your dad is a land lubber and probably has never worked with gavonic corrosion. Boats are an odd ball situation, AC, DC, corrosion, stray currents in the marina....... stuff you normally do not encounter on the land side.
If your metal parts are wasting away quickly there is a big problem. Since you have a wasted piece you can trace the electrical route. Ask yourself how would electricity (ac or dc) get to this metal part. It would get out by the water connection (electrolyte) to any other metal part in the water. also, closing a metal thru-hull does not stop the electricity. A plastic one probably does isolate the part but that depends on what else is connected to that water circuit. Example the strainer is connected by salt water to the water pump. The pump impeller is metal and so is the motor shaft which is grounded to the motor case which is grounded to the common ground point
Prepair to flame guys: It is better, on fiberglass boats, to isolate to the maximum extent possible, all your metal thru-hull items from each other. The rational is a single metal part that is not electrically connected to anything else will not corrode. By bonding all the metal parts together you are creating batteries and ground paths between the various parts. The bronze thru hull bonded to the stainless steel prop shaft will act as a battery. Two thru-hulls on opposite sides of the boat will provide a better path for marina stray currents than the salt water and the side that the electrons leave on will corrode. There are lots of other reasons and situations as well.
 
redunculous

redunculous

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May 13, 2011
420
Hunter 40.5 Legend Jupiter
Bill I hear you

Luckily he did a lot of work on the old Subs 'back in his day' and when he speaks about it he sounds just like you did above ;)

I'm going to read your post a few times until I understand it...
 
fstbttms

fstbttms

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Feb 26, 2011
1,440
Achilles SD-130 Alameda, CA
alexco38 said:
The zinc on my boat has been there for 5 years with a Galvanic Isolator. My next door has to replace it every year. He even have edging on the prop face. Not good. We are in fresh water.

I'm an EE
Click to expand
I hope when you say "zinc" you are using the word to mean "anode". Freshwater requires magnesium or aluminum anodes, never zinc.
 
redunculous

redunculous

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May 13, 2011
420
Hunter 40.5 Legend Jupiter
fstbttms

Whilst your here

How often do you suggest diving the hull and cleaning it off?

Probably a broad question due to areas and temps etc so I apologise if it is

I saw your video a while back of you giving the buildup a whipe off a hull and wondered when it should be done

Kind Regards

redunc
 
fstbttms

fstbttms

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Feb 26, 2011
1,440
Achilles SD-130 Alameda, CA
redunculous said:
How often do you suggest diving the hull and cleaning it off?

Probably a broad question due to areas and temps etc so I apologise if it is
Click to expand
Hull cleaning frequency is absolutely dependant on local fouling conditions. For instance- here in the SF Bay Area, every two months is ideal. In San Diego, every three weeks is what works. It looks like you're in Florida, and I'm going to guess that you should probably be having your hull cleaned every 3 or 4 weeks. But that's just my guess. A hull cleaner who actually services boats in your area would be better able to advise you.
 
redunculous

redunculous

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May 13, 2011
420
Hunter 40.5 Legend Jupiter
fstbttms

Thank you, I fancy doing it myself to see how tiring it can be for the first go

Will have a look through your posts for some more info and will speak to some people in my area.
 
fstbttms

fstbttms

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Feb 26, 2011
1,440
Achilles SD-130 Alameda, CA
redunculous said:
fstbttms

Thank you, I fancy doing it myself to see how tiring it can be for the first go

Will have a look through your posts for some more info and will speak to some people in my area.
Click to expand
Bear in mind (whoever does your hull cleaning) that relatively frequent, gentle cleanings will greatly extend the useful life of your anti fouling paint as opposed to less frequent, more abrasive cleanings. Big money saver in the long run.
 
redunculous

redunculous

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May 13, 2011
420
Hunter 40.5 Legend Jupiter
fstbttms

Thank you for the heads up

I take it a regular light grade scouring pad would be the ticket? (not sure if scouring pad is the same for the US but the green pads you can scrub pans with)
 
fstbttms

fstbttms

.
Feb 26, 2011
1,440
Achilles SD-130 Alameda, CA
redunculous said:
fstbttms

Thank you for the heads up

I take it a regular light grade scouring pad would be the ticket? (not sure if scouring pad is the same for the US but the green pads you can scrub pans with)
Click to expand
Of course you'll use whatever is necessary to remove the growth but always use the softest cleaning media possible. A white pad is preferable.
 
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