Sulphur Smell and Strange Discoloration of Plastics

[jdougall]

Hello,

I am battling a strange problem on board which is nowcausing me concern and I am wondering if anyone has ever experienced a similar case.

On entering the boat I smell quite a strong sulfur smell. It is the same smell that would come from a head that has not been used in a while however the smell is not coming from the heads. I have alsonoticed that nearly every power lead (plugged in or not) and some other soft plastics/rubbers have changed color to brown. I have also noticed that certain coins I have on board and other copper pipes are being tarnished and turning silver.

I had quite an amount of sea water come in to the bilges when an a/c pump was changed and am thinking that there may stillbe some trapped somewhere. The boat was also closed with no ventilation for a few weeks and would have become quite hot inside.

The strange thing is that the discoloration has occured to plastics (mainly power leads) regardless of where they are. The inflatable dinghy which is stowed in the bow now has 2 brown handles. The shore power lead is brown (only the part that is inside the boat). USB cables for pc now brown.

I am concerned that there is a very corrosive gas or substance on board.

Any shared similar experience would be really appreciated.

Many thanks,

John.

[GordMay]

Greetings and welcome aboard John.

I'd suggest that you check out your batteries & charging system.
Overcharge currents, coupled with high battery temperatures, can cause a battery to release significant amounts of hydrogen sulfide (hydrosulfuric acid or sewer gas - rotten egg smell), and sulfur dioxide (smells like a burnt match).

[jdougall]

Thanks very much Gord. I am having the batteries checked right away. I do know that there is one which needs replacing so this may be the culprit. Do you think this gas could also cause coins on board to turn from brass to silver and my copper pipes to turn black?

[gonesail]

i had the same thing happen last summer .. the bad smell not the colors changing. it was really nasty and took a while to ventilate. i'm pretty sure (as gord said) it was the charger boiling the batteries .. i am guessing there was some kind of power surge or failure or combination of the two that caused it. worrisome but it has not happened to me since then.

[speciald@ocens.]

Your batteries are venting

[GordMay]

Originally Posted by jdougall

... Do you think this gas could also cause coins on board to turn from brass to silver and my copper pipes to turn black?

YES.
Silver and it’s alloys tend to tarnish in gaseous atmospheres containing hydrogen sulfide or other sulfide compounds, even in small concentrations, resulting in a dull or black finish.
Copper reacts with hydrogen sulfide in a similar fashion as silver, because both elements have the same outermost electron shell configuration according to the Periodic Table. However, copper is more reactive than silver, and after the initial tarnishing by hydrogen sulfide to produce a red or dark brown surface, it can further react with carbon dioxide in the atmosphere to eventually produce a green patina.

[sandy daugherty]

Gord, you are a treasure.

[GordMay]

As Mark Twain said: "I have been complimented many times and they always embarrass me; I always feel that they have not said enough."

[jdougall]

Gord, thank you so much. All you have said makes perfect sense. On examining the services bank, we found one battery in need of changing (it was 1yr older than the others). The boat had been locked up and batts on charge for many months. Although the battery doesn't seem swollen it must be the cause - the discoloration of the cables is immense. Thanks again - I hope to be able to offer you some help in return.
Kind regards, John.