Help Needed, What Is the Cause and How to Recover it?

[Xland]

I just took delivery of a 20 yrs old Jeanneau Sundance Dance 36 yesterday. Today was spending time to explore all the hidden parts of the boat, and encounter this which I have not idea how to deal with it.

It's located below the Aft Cabin where the batteries stored. It looks like water plus battery causes this.

Experience sailors, boat owners please help take a look and advice how can I deal with this.

Thank you.

[hoolie]

It looks like a corroded earth connection to a keel bolt to me. The copper has virtually disappeared so I don't think you can do much there and you'll need to find another way of earthing the keel.

Our earth braid has corroded away pretty well all along and is on my list of things to do when the more urgent things have been dealt with ... ...

[Boracay]

It could be a good idea to delay major surgery till the boat is out of the water!

[Cheechako]

not found on survey?very strange looking thing for sure... is that a big hump I see? Is it glass over a keel bolt or...? looks like battery acid in contact with copper... at least color wise...

[Therapy]

Beatiful color. Absolutely gorgeous.

Looks like another planet good for sailing.

But in the bottom of the boat? Maybe pour a box of baking soda on it till you can figure it out.

[sailorchic34]

ditto on the baking soda and a sprinkle of water.

[bobconnie]

Any surveyer who missed that mess sure did not do his job ! Get soda and water to it and see whats left of whatever it was before this happend to it !

[Rocketman]

It looks like an Alien is trying to come aboard? Is that a seperation in the fiberglass that has caused a big bump? Or is the big bump supost to be there? For sure it looks like a copper conection gone bad. If it is below water line I would do as other have sugested, put some baking soda on it and see what's under it. Then be careful. May have to haul it out to make a full evaluation.

[ozskipper]

After the clean up, make sure that your batteries are in battery boxes in the future. This will help to prevent future spills. http://img513.imageshack.us/img513/6...7434716tl0.jpg

[Auzzee]

It looks as though someone has spotted the problem and covered it with resin as a stop gap. The verdigris is from copper in contact with acid or corrosive salts. It could simply be a keel bolt end (bronze contains copper), or a dynaplate bolt.

It doesn't look like it's just surface spillage from battery acid as there sure appears to be an anode there, beneath the grunge.

One thing is for sure, surgery of some form is required, but the skin of the bubble shouldn't be burst while the boat is in the water. There may now be a void in the hull, which could be a primary site for osmosis.

[delmarrey]

Looks like an internal blister. Or maybe the boat has cancer.

[Xland]

Thanks Guys for the inputs.

I did a further check, analysis and asked the seller.

The batteries are Gel batt so no acid involve, and the batts were installed since 2008. So batt acid involvement was ruled out...

However, I did spot water around the area, which trace back to the stern's compartment where the spare anchor and gas tank are stored. That compartment is wet and have water after rain, so the leak is from there. Need to trace how the water enter the compartment.

The strange time does look beautiful and like something from limestone cave.

Keel bolt??? I will need to check again, but will definitely do baking soda and water..

[Therapy]

Originally Posted by Xland

However, I did spot water around the area, which trace back to the stern's compartment where the spare anchor and gas tank are stored. That compartment is wet and have water after rain, so the leak is from there. Need to trace how the water enter the compartment.


..

If you think it is coming from that locker then you have a gas vapor issue to worry about too.

[Xland]

Originally Posted by Therapy

If you think it is coming from that locker then you have a gas vapor issue to worry about too.

Exactly! I reckon the 3 main hazards for a boat are Elect, Leak and Gas! I think we cannot live without Elect and has to constantly deal with leaks, and the two are already quite a handful so I decided to remove the Gas! so one less to be worried about.

[David_Old_Jersey]

It is certainly a strange one!

I would try and find out from a sister ship what that area usually looked like.

If the whole lump is "extra" (and not just the discolouration) then my answer would involve a drill / sanding disc / angle grinder.....gently at first!

The cause has me flumoxed though - maybe it is build up on the inside bolt(s?) of an anode? (that had been disconnected by a PO?).

Of course if you were selling the answer might be a quick clean and a coat of paint .