Do I have a problem??

I just purchased a 36' steel sailboat. It's five years old. The survey with "ultrasound" (not sure what the correct term is) showed no corrosion.

So far, so good.

During the survey, it was noted that 4 of 6 zincs were gone. As in completely gone; only the rudder zincs were left. Given the level of maintenance that this boat has received from the prior owner/builder, this was very surprising. I had them replaced immediately, even though the boat was not yet mine. That was about three weeks ago.

The boat has a corrosion meter. You press a button for 5 seconds, let go, and read whether you are underprotected, overprotected, or Goldilocks just right.

Right after the zincs were put on, the meter (boat in the salt water) read on the high side of the green area, i.e, just under over-protection. Last weekend, the meter read low side of green area, i.e., just above the under-protection indication.

The meter did not read differently at two opposite ends of the harbor, out of the harbor at anchor, or AC unplugged or plugged. Next weekend I'll try with the boat batteries unplugged. Turning on or off the DC circuit made no different either.

The fact that the zincs were surprisingly gone at survey, coupled with the now dropping corrosion meter reading, has been eating at me (pun??).

I'm completely new to metal boats. I know very little about them and even less about 'lectrical stuff, but I'm willing and eager to learn. I do know that the appliances (AC and DC) on the boat are not grounded to the hull. Plus, the prior owner did not, and I do not, keep the boat AC plugged in.

The boat has all kinds of electronics: solar panel, SSB, invertor, refrigeration, radio, hot water heater, lights, pressure water, CD, TV, etc., etc. Not my style, but otherwise the boat is just right.

There are one or two electric bilge pumps in the bilge. There is water in the bilge just in front of the engine, where the shower drains. I have not checked the pumps for loose wires, as the surveyor had his steel boat severely damaged from stray current in that location so I'm sure he checked that area real close given his experience. Besides, he was so incredibly detailed in all other aspects of the survey.

Should I be worried that the corrosion meter seems to be sliding out of the green and into the yellow--under protection area?

Of so, what do I do about it?

Any guesses why the corrosion meter has shifted?

TIA.

-John.

 

I would giveit a little time to see if it stabilizes in the protected zone while keeping a careful eyes on the zincs and other critical areas. Meters can be fluky as all electronic devices can at times.

Finding a reputable marine electrician should be straightforward in your area. That would be my next step if trouble persists.

Years back I worked as first mate on a 68' motoryacht. It's electrical system was so mysterious in it's workings that, to me, it seemed possessed. My captain, very experienced, was likewise perplexed.

Hope it all works out well. What design boat did you purchase? I hope to retire (a long time off) in SE Alaska and will do so in a steel boat.

TGoz

 

your boat quite simply has too many zincs, on Nimbus(alloy), there is one,

 

Then why is the corrosion meter drifting into the unprotected area?

 

It's a derivation of Ted Brewer's Humoric (sp?). A little more bow, a little more sail, and a little deeper long-fin keel.

We purchased it for our retirement, which is still a 100 years from now. But the intended cruise area are points between Seattle, WA and Seward, AK.

Our first boat was out of Seward, Alaska. We love that PNW marine enviroment.

Ironically, the boat is moored in Anacorates WA. The first time I ever experienced the PNW marine environment,which was when I was about 23, it was very near there. Full circle, I've come.

 

I dunno, I no zilch about these meters, do you have ac in? do you have transformer, if do check across earth there should be no continuity between Gr in and Gr out

 

The boat has alternating current (AC) [not air conditioning] but we don't use it 99% of the time. The boat's AC is left unplugged.

I've heard about too many stray currents with AC. My last boat didn't have it, so it's easy for us to continue to go without AC.

One thing I left out in my first remarks above is that the yard did not have the same teardrop-shaped zincs as were originally on the boat. So, I had some plates (6"X3"??) drilled out and installed instead. They do present more surface area (not to mention drag while sailing) than the teardrop.

The boat is five years old with no corrosion. The zincs have worked thus far. Seems to me it's gotta be stray current in the water.

Should I hang a large zinc in the water connected to the boat?

 

Thanks, but I'm a little dense. How do I watch underwater zincs?

 

You dive in for a look. Whoever cleans the bottom should be able to tell you how they are doing.

 

1. The water here is fricking cold.

2. Water in marinas is fricking dirty.

3. There are enough stray currents in marinas that several people die in the US every year from swimming in marinas. They don't get electrocuted. The electrical current freezes their muscles and they drown.

At anchor, yes I could check, but there is enough water current out here that I would want a 100' drift line to catch should I not be able to make it back to the swim platform.

OTOH, when we lived in Alaska we did go swimming in the salt water, but that was only on summer days, soon to be in short supply. But, oh, my heart.

 

Good points hiracer. Cold, filthy, electrified water is not fun to dive in. So I agree that diving down to check zincs ain't gonna be easy.
I wouldn't have much confidence in said corrosion meter; such gadgets are not known for lab-grade accuracy.
Shortly after fresh anodes are installed, they develop a coating of zinc oxide that will, to some extent, impede their effectiveness compared to the brand-new anodes. If things don't stabilize eventually, you might try to periodically scrub the oxide off the anodes to expose more metal. Normally this is not a huge issue though.

 

Leaving this afternoon to see the new boat again! Will check to see what the meter says. If it stabilizes, I'll feel much better. The business about zinc oxide makes sense to me.

The bottom needs to be painted, which will likely be next month's project. Visual inspection at that time should tell me much.

 

Report after the weekend:

The corrosion meter was in the low yellow zone, "Freely Erroding." The marine electrician concluded that the corrosion meter is reading the corrosion from the sending unit of the corrosion meter itself.

Diver reported that the zincs are in mint condition. He reported that corrosion meters never work correctly. Throw it away, he said.

Prior owner reported that corrosion meter always worked fine for him, but the boat has been in the care of the listing broker for the last two years.

Saturday evening as we were about to anchor the stuffing box came apart and we took in LOTS of water. Was an interesting evening getting the boat back to marina and then hauled out. She's on the hard now. Happy to report that the electric and especially the manual bilge pumps work well.

I've never stood on a sinking boat before. It was surreal moment, I assure you.

Never . . . a . . . dull . . . moment . . . here.

 

So did the stuffing box come apart from bolts/ fasteners coming loose, or was it a corrosion issue? I assume the former, or you would have mentioned it.

The diver & electrician may have cost somewhat but, I would think the peace of mind & confidence in your boat obtained would be well worth it!

When I first started sailing I had a "Sunfish" like sail boat. It leaked bad at the rudder/ stern connection. The previous owner had plenty enough glass built up around there that there was obviously a problem.

We would drain it after each time my friend and I took it out solo by propping the bow up on a cooler. One time my friend came in and said it was OK, did not need drained. Should of known better.

Everything was fine on the outward tack. As I taked around to reach back to shore she started taking on alot of water, the fitting had further loosened. I was about 75 feet from the dock when I decided it was time to bail. After carefully clearing all the lines (not many on a Sunfish) I went over the side, and taking the bow painter in hand, sidestroked to shore, boat in tow, and still sinking. Would of never made the last feet had I stayed abourd. The kids fishing on the dock found it enteraining. Later on watching "Pirates of the Caribean" I realize how close I came to stepping off the boat right as it made both the dock and bottom similtaneously just as Johnny Depp did. That would have been pretty cool.

Got of the subject, sorry all.

Congrates on getting things figured out Highracer.

TGoz

 

Funny story about the Sunfish type boat.

I have not received a full report about the stuffing box, but the prelimary report is that it was garden variety stuffing box problem, not a corrosion issue.

Apparently this is a common problem. Three boats were hauled the same day by the same yard for the identical problem. Wow.

Cost: The electrician was very reasonable. The diver I just happen to meet on the dock and simply had to swim a few yards my way to look at the zincs. He didn't want to charge, but I insisted of course.