So... Is This Corrosion?

[DBG8492]

New to me forty-year-old Island Gypsy - nothing was said about this in the survey - I checked. This is the starboard exhaust outlet, but the port looks just like it. Both outlets are made of bronze, like all the rest of the hardware on the boat.

I should note that none of those drips are wet and nothing smells like diesel. I'm wondering if the brown drippings are from some sort of bedding used in construction.

To me, the green just looks like normal verdigris from the bronze, but the Admiral blew a gasket when she saw it today.

 

[Comodave]

It looks like there was a leak at one time or another. Maybe put some paper towels under it and check them periodically to see if they have been wet recently l. The green is pretty normal.

 

[boomerang]

The exhaust flanges might need rebedding or the hose clamps might need tightening but wow, I wouldn't sweat it too much...at least the access looks like you can get to it! Mine is buried behind built in draws and cabinetry somewhere!

 

[DBG8492]

The exhaust flanges might need rebedding or the hose clamps might need tightening but wow, I wouldn't sweat it too much...at least the access looks like you can get to it! Mine is buried behind built in draws and cabinetry somewhere!

Yeah, the pic is deceiving.

The one in the pic (starboard) is buried behind the nightstand so at the very least, that would have to come out unless you're a very tiny person who could fit into the space that would normally be occupied by a drawer. I can almost get one head and one shoulder in there, but I'm pushing 250 so that's all that's going in there - not sure I could reach all the nuts to get a wrench on them. The Admiral took the pic on zoom from just inside the drawer.

The port side is inside a locker and by contrast a lot more accessible.

 

[O C Diver]

Get some estimates. Sometimes things just look expensive to remedy / restore. A competent yard may view that as a modest repair, especially if they've done it before.

Ted

 

[SteveK]

I will add this sounds like a recently done survey, have you sent that picture to the surveyor?

 

[BruceK]

If access allows, try cleaning up and see if it recurs. Try a spanner on the nuts too.

 

[KnotYet]

At 40 years old you can expect that the bedding and the hoses have had a long life.
It may be time to renew both. That may be the first sign of leaking or cracked hoses.
Look at it like an early warning sign.

 

[Bmarler]

I’m with Bruce, clean it up first. Long handled brush and some cleaner of your choice. Dry it good and hit it with some boeshield t9 or similar. Monitor for leaks. Fully address at next haulout.
Maybe try to clean up the bonding connection too. I doubt it’s making good contact.
This would be a “when I have an hour or two to spare” job. Not a top priority.

 

[tiltrider1]

What I am seeing is heavy oxidation, which is a form of corrosion but caused by oxygen in the air. It appears like the hose clamps on a wire reinforced hose failed in the past, leaking rusty water and exhaust gasses in to the space. This of course made the oxidation heavier.

I do not see anything of concern which probably is why no write up from the surveyor.

 

[Greg QS]

I am surprised at the responses. That is a pretty big pile of corrosion bits on the hull. That used to be metal. Definitely looks like a leak to me. All the parts there look old. I would before this season at least remove and re set, Replace if necessary. Check the hose also . Check the other side.
Does the bottom paint burn up around the outlet? Your bonding wire looks heavily corroded. Electrolysis can damage the metal to a point of brittle ness.

Ounce of prevention is worth a pound of cure.

 

[CharlieO.]

The area I circled in red is where I would be concerned, it almost looks like it is leaking on the shoulder between the flange and the pipe. Also, I changed out my exhaust hose when it looked similar to yours, I was amazed to see how much it was compromised when I started removing it. It just looked old and dirty but serviceable - but once I started moving it it showed a lot of cracks everywhere. So I removed my exhaust hose and my exhaust thru hull and resealed it and replaced the hardware while I was there. Wasn't much fun or difficult but was necessary in my opinion. Project creep - of course when I was in there I ran new bonding wire and rebed my swim platform brackets along with replaced the bracket backing plates and painting the lazarette. And it all started by removing a water tank to repair its leak.

 

[DBG8492]

So the surveyor is someone I've worked with before - we have a very good working relationship. I spoke to him last night and he said I'm looking at forty years of verdigris on the bronze, not corrosion. That's why there was nothing in the report.

At some point in the past, there was a leak where at least one of the old hose clamps failed - those are the bits lying on the hull. This is where the brown stain came from as well. The hose is in good condition (likely replaced within the past ten years), and the clamps are good stainless.

His advice was to clean it up as best as possible, check the clamps to ensure they're tight, and monitor for future leaks.

I trust his assessment.

 

[BB-marine]

I would question the integrity of the exhaust outlets. I assume they are at water level and partially submerged when at the dock. Are the thru hulls bonded on this boat? If so they may have missed the exhaust outlets. There are signs that there was a leak path, exhaust hose or exhaust outlet and may be compromised. I am curious what the wire is for that is attached to the fastener forward the outlet. Is that part of the exhaust outlet and is that a bonding wire. If so that may be compromised. It is not a proper bonding wire. This may not be a big deal but it is definitely worth looking into. This is not a resent issue it has been going on for a while. This was a good find on your part. Now its time to dig a bit deeper and not speculate if it is an issue or not. 40 years of service the exhaust hose is due for inspection and maybe replacement along with the exhaust outlet. Good luck.
Brian

 

[Gdavid]

It looks pretty bad to me. I would disassemble and re-bed the thru hull fitting at a minimum and preferably go ahead and replace it. There are fiber reinforced synthetic replacements that negate the concern for corrosion. There should be a date on your exhaust hose, and it is likely due for replacement as well. If this fitting is deteriorated and fails or allows the hose to slip off when backing down, you would have a lot of water coming in quickly.

 

[SteveK]

So the surveyor is someone I've worked with before - we have a very good working relationship. I spoke to him last night and he said I'm looking at forty years of verdigris on the bronze, not corrosion. That's why there was nothing in the report.

Glad to hear this. Do clean up, even paint if you can and monitor.

 

[tiltrider1]

Verdigris just means oxidation specific to bronze. In other words just heavy oxidation as I mentioned in post #10.

 

[Delta Riverat]

So the surveyor is someone I've worked with before - we have a very good working relationship. I spoke to him last night and he said I'm looking at forty years of verdigris on the bronze, not corrosion. That's why there was nothing in the report.

At some point in the past, there was a leak where at least one of the old hose clamps failed - those are the bits lying on the hull. This is where the brown stain came from as well. The hose is in good condition (likely replaced within the past ten years), and the clamps are good stainless.

His advice was to clean it up as best as possible, check the clamps to ensure they're tight, and monitor for future leaks.

I trust his assessment.

I agree. It would be different if you couldn't see the nuts anymore but you can and they appear to have sharp corners. Yeah, this stuff has been growing for 40 years w/o a touch.