Now a believer in bonding

[zboss]

So, in preparation for our heading south this week or next, I started going through my checklist. You know... things screwed on tight, no cracks in things, etc... when I noticed that there was some water under my sink.

Being that I just replaced my sink thru-hull and associated hosing, my immediate reaction was something wasn't tightened up enough. Well, I tightened all up and wiped up the mess. Next morning... more water. OK, turn off seacock and wipe up mess. A few hours later, more water. Not a gusher or anything but enough to make you go 'Hmmmm'.

That is when I noticed a crack in my raw water strainer which is also in under the sink.

I go out and get a new stainer. In the processes of taking the old one off, in addition to the crack in the tube of the strainer... this is what happens.

The strainer was not bonded, unlike just about everything else on the boat, and after 26 years this is what happens. It does not happen over night but the steady progression is guaranteed.

[colemj]

We just had this happen to us. It is probably not caused by not being bonded, but rather by a yellow brass/bronze nipple being used between the strainer and the elbow.

I swear that if you hadn't sat that on a teak deck for a picture, I would have thought you gained access to my picture files!

Mark

[Aikiguy]

Was there anything wrong with the actual raw water strainer, or just the close nipple that was connecting it with the elbow?

From the photos the raw water strainer looks fine.

Looks like a case of dissimilar metals, not a bonding issue.

Guy
:-)

[SVNeko]

26 years, come on.

[onestepcsy37]

zboss, that's got nothing to do with bonding. looks more like a problem with the nipple, probably disimilar metals. if you can check on that i'd like to know.

i'm not bonded; 34 year old boat with all bronze through hulls, not one is connected to another, nor is anything else on the boat - electronics included. all original bronze is still in excellent condition. i greased every through hull last year and checked their condition so i'm pretty confident in them.

and when i took a direct hit by lightning a few years ago i think that not being bonded is the reason i had so little damage. a couple of light bulbs popped and i lost my vhf and depth sounder.

[rebel heart]

I stopped bonding thru-hulls because my forward head thruhulls got burned in two years in a marina with bad wiring. They were closest to the power pedestal and well, there you go. Would have been a good place to put a zinc fish in the water.

[zboss]

There were two fittings on the boat that were not bonded and they both looked like this. All the other fittings looked good but I replaced them all anyway. You may be right about the brass/bronze.

The groco I replaced this with comes with a bonding screw.

The strainer glass was cracked. Hence the leak. I may have done it myself when I was working on the boat this summer and just never noticed.

My teak is crap! Its soooooo low on the list of to-do's right now that I leave it to a sunny day... or not

[familycruisers]

On a side note. You headed south yet? Would imagine Herrington Harbor is getting a little chilly!

[sailorchic34]

Ah that sure looks like rust in the photo at the break and that is a black iron pipe connected to the other side of the bronze elbow. Bonding would not have saved that. Iron is a anode to bronze so it sacrifices itself. I'm thinking somebody used an iron pipe nipple between the bronze sea strainer and bronze elbow.

[Steve Bean]

It looks more like dezincified brass to me. Hard to believe somebody could put an iron nipple there. And how could iron last that long?

[Celestialsailor]

Originally Posted by colemj

We just had this happen to us. It is probably not caused by not being bonded, but rather by a yellow brass/bronze nipple being used between the strainer and the elbow.

I swear that if you hadn't sat that on a teak deck for a picture, I would have thought you gained access to my picture files!

Mark

Ya...I'd have to agree...I only bond my copper plate which I use as an HF ground plane to a zinc plate.

Originally Posted by rebel heart

I stopped bonding thru-hulls because my forward head thruhulls got burned in two years in a marina with bad wiring. They were closest to the power pedestal and well, there you go. Would have been a good place to put a zinc fish in the water.

When I bought my HR, I was inspecting the through-hull under the galley sink and it snapped off in my hand. There was a zinc nearby which for some reason had a wire going to the ground of the VHF. Good grief!

[sartorst]

I too have stopped bonding my boats through-hulls,after many years of being bonded and replacing zincs only because the diver was there or the boat was out of the water I had become complacent and had not been replacing as before well something in the marina or a boat near me changed! next inspection ,no zincs and prop badly eroded and zincs were needing replaced very often until I un-bonded all systems things went back to the way they were, only being replaced because I/we were there

[zboss]

Originally Posted by sartorst

I too have stopped bonding my boats through-hulls,after many years of being bonded and replacing zincs only because the diver was there or the boat was out of the water I had become complacent and had not been replacing as before well something in the marina or a boat near me changed! next inspection ,no zincs and prop badly eroded and zincs were needing replaced very often until I un-bonded all systems things went back to the way they were, only being replaced because I/we were there

How often do zincs normally need replacement on a cruising boat? We also have a twinvee 20 foot with dual outboards and we only have to change the zincs once every other season.

[sailorchic34]

Originally Posted by Steve Bean

It looks more like dezincified brass to me. Hard to believe somebody could put an iron nipple there. And how could iron last that long?

Ah but brass would be yellow at the break and slightly shiney and not rusty flaky looking. Brass does not flake as it corrodes, it pits, as does dezincing and the inside bore of the nipple is smooth well the small part I see. Look at the edge of the broken nipple. That looks like flaking rust to me.

Plus that 4" pipe nipple on the other side of the brass elbow IS a black steel pipe nipple. You can see rust in the tooling marks.. So odds are where you have one black steel fitting you have another. I expect it was installed only a year or two ago. Probably by a highly qualified island marine mechanic. Zboss is located in the BVI or about down there.

Zboss: if brass pipe is not available. use brass hose barbs and lengths of rubber hose. Then Bobs your uncle.

Me I would replace the sea strainer too as some of the tin, in the fitting end of the sea strainer may have gone away too. That's real heavy patina on that end of the sea strainer.

[rebel heart]

Originally Posted by zboss

How often do zincs normally need replacement on a cruising boat? We also have a twinvee 20 foot with dual outboards and we only have to change the zincs once every other season.

It depends entirely on the marina and the boat. In some places with crappy wiring and/or bad neighbors, you can burn out a shaft zinc in a couple of months. At anchor and with a galvanic isolator? Two years? No idea really.