Aluminium Pitting?
Submitted by Bucko on Mon, 2022-09-12 09:10
Guys,
Has anyone seen anything like this before?
Its in the chines, mostly likely below the waterline. Hole does not go right through the plate, but its 2-3mm deep.
The paint around it has blistered, not sure if this is from the hole being there or if the hole is caused by something under the paint?
Boat is 5 years old....
Any thoughts?
Image Upload:
little johnny
Posts: 5360
Date Joined: 04/12/11
Is electronics
On boat earthed out correctly ( no earth to hull) that’s bad
Swompa
Posts: 3893
Date Joined: 14/10/12
Do you have an anode on the
Do you have an anode on the boat?
The boat is certainly trying to get some charge out of itself. Time to check wiring i would think.
Mooseknuckle
Posts: 110
Date Joined: 14/05/13
Electrolysis
Would daresay if boat is only 5 years old then been there developing from the start.
Dissimilar metals or stray electrical currents can cause it - even the paint (especially anti-foul) if it is wrong spec and has the wrong metals in it (like copper).
Not much to do but internet research electrolysis causes and try to find the cause on your boat - ours was wrong antifoul.
Good luck
Moose
Mooseknuckle
Posts: 110
Date Joined: 14/05/13
Electrolysis
Would daresay if boat is only 5 years old then been there developing from the start.
Dissimilar metals or stray electrical currents can cause it - even the paint (especially anti-foul) if it is wrong spec and has the wrong metals in it (like copper).
Not much to do but internet research electrolysis causes and try to find the cause on your boat - ours was wrong antifoul.
Good luck
Moose
sea-kem
Posts: 15002
Date Joined: 30/11/09
Something like that is
Something like that is usually where a screw or something metallic has cooked through, damn shame.
Love the West!
Bucko
Posts: 144
Date Joined: 08/05/10
Hi Guys, Thanks for the
Hi Guys,
Thanks for the comments.
In regards to wiring, all electronics were installed by boatyard at time of purchase, I really haven't done anything myself.
I did buy this boat new from a local boat builder, who I have also contacted today.
My main question is why has this happen and what needs to be done to prevent any further issues.
I am waiting on their response....
I don't know if theres an anode on the boat, I will have a look when I get home. I don't remeber seeing one.
Thanks
little johnny
Posts: 5360
Date Joined: 04/12/11
Straight out yard
I know someone who’s boat started straight away. Everything was earthed out to hull . Bad move . Some don’t care / some do
Shark1
Posts: 1086
Date Joined: 21/05/12
check for continuity between
check for continuity between battery negative and the hull- nice open paint free spot
if it gives a reading well... ive seen a brand spanking boat on the ramp with the negative just tapped straight to the hull "yeah my m8 is an autoleccie, he did all my wiring"
as for anode -will only work while wet /submerged
there was a batch of ali - yes about 5 - 7 years ago that came into Oz , was supposed to have been marine grade - it wasnt, I know of 2 build by Stacer that was replaced/refunded, when u tried to weld it, it would just fall apart, wouldnt /couldnt even get a puddle going
does your motor anodes show any abnormal wear?
Bucko
Posts: 144
Date Joined: 08/05/10
Dunno mate, will take a good
Dunno mate, will take a good look when I get home today and put some pic's up of anodes.
When you say check for continuity between battery neg and hull, I assume you mean with a multimeter.
I'm no sparky, but I will give that a go too.
This boat was not made by some backyard mob, the people who made it should know what they were doing....
I trust they do and there's another explanation for this.
Will update if I find out what that might be...
Shark1
Posts: 1086
Date Joined: 21/05/12
yep multimeter - setting
yep multimeter - setting normally is the Ohm sign
1 lead to neg baterry terminal - other to hull
check with motor on and off , also check between trailer and boat, if you around rocko i can lend a hand
Swompa
Posts: 3893
Date Joined: 14/10/12
This boat is a Chivers, isn't
This boat is a Chivers, isn't it?
I wonder if the plate had a hole in it that was plugged prior to painting. Can you see what's on the inside?
carnarvonite
Posts: 8672
Date Joined: 24/07/07
Inside
I'd be having a look at what was inside. To me it looks like you have had some dissimilar metal sitting inside and the reaction has drilled through the hull.
Had one like it on my boat, found a stainless bolt sitting in one of the pockets inside. Drilled it out and mate filled it with weld
Belly Fish
Posts: 499
Date Joined: 09/03/12
Another angle...
I had a hole develop in the side of my boat.....I have photos but don't know how to add them to this post
Mine is a very well known brand, but I won't mention it publicly, although there is a photo of it in my avatar.
When I finally found out what was going on it was very interesting and I have since seen a couple of other boats from te same builder with exactly the same issue.
What was happening was that salt water spray was vortexing up along the gunwhale and dropping into a hidden compartment just aft of the transom. This was especially evident in a seabreeze (problem is on the port side). I didnt know this water was there until it ate a hole in the side plate, around where yours is. The salt water obvioulsy became super corrosive as the water evaporated off, leaving a brine.
Giveaway for mine was that this "brine" leaked out of the hole once it ate through.
It's worth a look
ChopChop
Posts: 69
Date Joined: 17/01/15
How did you/they fix it?
How old was the boat?
Belly Fish
Posts: 499
Date Joined: 09/03/12
Probably 12 years when it appeared
I got a mate who was once a ali boat builder to cut a section out and reweld in a new piece.
I then cut in a circular inspection hatch in the transom (screw in lid type) so that I can easily access this section. Now, after every trip I inspect it and sponge out the salt water, rinse with fresh water and sponge that out. Bit of a pain, but it works. If its calm, there is no water in there...it only happens when seebreeze spray is running down the gunwhale.
I did try and fix it by adding an extra piece of ali under the side coaming so that the water would hit that and drop inside the deck area but it was only partially successful. That side is where all the engine cables and electrical leads run so I can't close it off completely.
ChopChop
Posts: 69
Date Joined: 17/01/15
Dirty weld?
Is there a weld (ground flat) there? I have a few holes appearing in the same place that look to be from a poor weld. Gas bubble or something.
scubafish
Posts: 962
Date Joined: 15/08/12
eletrolicis
Check the boat for power to the hull when the motor is running and with the ignition off.
Multimeter to neg batt and + to hull.Stray current can also happen from another boat in a marina.
Just wondering if that hole is old damage from a s/s ball bearing fired from a slig ?
P.S
Also check the Trailer boat on and off.
http://img.gg/BQ91Sys