Galvanic corrosion in ally boats

 gday guys ive got a bit of a problem ive had my ally boat for 3.5 years now and the paint is bubbling near any hardware that has been mounted on the boat

the worst area was near the live bait tank and under the cushions where the steel staples used to hold the side cushions together have rusted the area behind them

the boat gets washed after each use with soapy water and hosed off after that i thought that this was all that was required

since speaking to the boat manufacturer they have advised that i should be using inox around all areas where things are mounted to keep the salt water out......

since looking into this problem ive come to know how much of a problem stainless and aluminuim have with each other and then when saltwater gets involved things escalate but they make products that slow the process duralac and you can sikalfex around the mounted hardware to help stop the saltwater getting in as well

neither of these things were done by the boat manufacturer and when i asked them about it they just said it was poor maintenance 

does anyone else think this is just a crap effort by the boat manufacturer i dont wanna name and shame the manufacturer but i think that its a bit shit and was wondering what other people think and if other boat manufacturers take more of an effort when mounting hardware to their boats

 

Image Upload: 

bouttime's picture

Posts: 703

Date Joined: 27/07/06

 Looks severe for a boat only

Sun, 2016-05-08 23:36

 Looks severe for a boat only a few years old. You should be using a paste such as duralac around stainless fittings which will help slow it down. I have also been told dont use car wash as it can make things worse. Just use water and a non corosive dish washing liquid. I have a bit on my boat its 8 years old but nothing like that. Just clean it up with some rust kill and respray will look like new.

Madmerv's picture

Posts: 672

Date Joined: 24/01/15

Metals + Water = Corrosion

Mon, 2016-05-09 06:07

 Can see why you are not to happy there. As you have stated putting a barrier between the dis-simmilar metals will help a lot but like everything in life the builder has to work to a price. If they spend the time / $ putting a rubber gasket between all the metals then the cost of the boat goes up corresponding to the effort. The competitors boats then look like a better option.

You are doing the right thing now by rubbing it back and giving it a respray. then go over the whole boat looking for the danger spots and try to fix them before a problem occures. 

If you add up all the time you spend working on the boat and then x by $200 or so then that might be close to the extra cost you would have to pay for the manafacturer to have done it in the beginning.

At the end of the day the problem is there because you are using the boat so i guess you are getting your moneys worth out of it. Wish i could say the same ATM.

____________________________________________________________________________

 Sometimes when the water is quiet, you can hear the fish laughing at you !

Saulty2's picture

Posts: 643

Date Joined: 28/05/10

thats major

Mon, 2016-05-09 08:46

think it has not been primed properly before painting, cant blame that on a few screws

Posts: 573

Date Joined: 23/04/14

Priming

Mon, 2016-05-09 11:54

Galvanic corrosion will usually show as an area where a substantial volume of the metal has disappeared due to corrosion.  I don't really see that.

Those large areas of flaked paint look more like the hull wasn't properly etched and primed prior to painting.  

____________________________________________________________________________

 

 

grantarctic1's picture

Posts: 2546

Date Joined: 03/03/11

Have to agree

Mon, 2016-05-09 14:54

Have to agree with comments above, the whole area looks a poor job was done on the painting. The corrosion has started with the screws/bolts , but shouldn't have spread out that far as in your picture.
Looks like it got under the paint and primmer, then took of like a race horse on meth .
As a suggestion, make sure you have not had an earth leakage around that area. Possibly a pump for the live bait tank. This would explain such a rapid corrosive effect.

ranmar850's picture

Posts: 2702

Date Joined: 12/08/12

What they said

Tue, 2016-05-10 16:12

 ^^^^  This will also inevitably happen if you  drill and fasten through an area already painted, you have just given the water a way under the paint and the process will not stop until you sand back and paint. You may also see it happpen where you have scratched clear through  the paint and primer.

Posts: 358

Date Joined: 12/05/12

agree with grantarctic LED lights

Tue, 2016-05-10 20:17

 Had LED lights under gunnels, wore out and were brittle and cracking, electric current going everywhere but where it was meant to...now no longer on the boat. 

Posts: 19

Date Joined: 02/07/15

When you put it back together

Wed, 2016-05-18 21:51

When you put it back together use Duralac or Mastinox on the fasteners and between different metals. This will help prevent disimilar metals causing corrosion.

Just make sure to wear gloves when using this stuff as its quite toxic, especially Mastinox.

 

 

Posts: 3

Date Joined: 18/06/13

primed up

Sat, 2016-05-21 10:12

 yer so ive sanded it all back and got some holes welded up and i have now got it all primed up using a 2pac epoxy primer 

and yer basicly i have brought a tube of the duralac (the new eqivilent that a different boat builder reccomended) and spoken to someone about the paint its a tabs boat built in qld and im not sure if there painting process is as good as some of the more expensve boats but i like the boat and i should have fully nipped it in the butt im going to take everything mounted on the boat and re mount with duralac and sikaflex its gonna be hard to blend the paint in but i got the paint colour matched and now im just waiting for a nice dry weekend so i can finish it and get the boat back in the water ill post some progress pics

 

Posts: 55

Date Joined: 06/02/11

tabs

Mon, 2016-05-23 08:43

 i have a tabs as well,mine has corrosion behind every stainless press stud,The press studs also had aplastic washer behind them to stop corrosion but the stainless screw is what did most of the damage i think.

My boat does have the same behind the cushioning but not the back deck like yours

yes i agree that they are a good solid boat and handle conditions great,mine is a 650 with verado 225hp

cheers rob

Posts: 3

Date Joined: 18/06/13

yer ive removed all the press

Tue, 2016-05-31 20:41

yer ive removed all the press studs the paint came up good mostly a few runs when we painted but ive sanded them back and im gonna re prime 2 sections and paint again

but yer i removed the cushions completly and everything is getting remounted with sika and duralac