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Electrolysis...and the poor start to a boating season.

Posted: Wed Jun 02, 2010 9:10 am
by Stripermann2
My friend traded his 1980 F30 for a smaller Wellcraft express last fall. (wrong move but another story.. :roll: )

The boat was in great shape when it was hauled for the season while the new owner installed some electronics and cleaned her up well. He since sold it this spring to another...After purchase, the boat was splashed and moved up the creek to another marina.
In the span of 45 days, the struts, rudders and props were destroyed! The boat began taking on water after a short cruise with the owner and made it back to our marina where dock workers made the emergency pull in the sling. Not sure what caused this electrolysis...improper electronics install and possible ground omitting or another boat at the marina with a serious electrical issue or perhaps the marina's dock wiring itself. Just remember, it doesn't take long for this gremlin to rear it's ugly head!

Here we have the starboard strut completely eroded from the hull and it's mount and hanging down along with unsupported shaft.
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Here is the port strut, oh wait...there is no more strut!
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Here the starboard strut is almost eaten away.
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In this pic, this is what is left of the port rudder. Just a nib...the starboard rudder is no longer in existing- completely gone. Notice there is no longer a zinc on the rudder, it use to be there.
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Posted: Wed Jun 02, 2010 2:01 pm
by Rodman
Holly ***, that's been in the water a little while too long.

Posted: Wed Jun 02, 2010 2:07 pm
by Stripermann2
Rodman wrote:Holly ***, that's been in the water a little while too long.
The rudders and struts were fine...this happened in just a little over a month's time.

Posted: Wed Jun 02, 2010 3:57 pm
by Rodman
Stripermann2 wrote:
Rodman wrote:Holly ***, that's been in the water a little while too long.
The rudders and struts were fine...this happened in just a little over a month's time.

wow thats crazy.

Posted: Wed Jun 02, 2010 11:50 pm
by rossjo
Better find the cause before putting it back in.

Beacon has the struts in stock - they're around $500/each.

It seemingly ate the bronze strut and rudder because they were softer than the Nibral prop and stainless shaft - but grounding may have had an effect as well - since the prop shows NO signs of erosion.

Someone needs to check the boat and see what is/isn't grounded, as well as what current is leaking on the boat or at the dock. This could be dangerous (electrocution) if theres a major AC leak at the dock.

Posted: Thu Jun 03, 2010 8:06 am
by Stripermann2
rossjo wrote:
Someone needs to check the boat and see what is/isn't grounded, as well as what current is leaking on the boat or at the dock. This could be dangerous (electrocution) if theres a major AC leak at the dock.

Yep!

Posted: Thu Jun 03, 2010 3:31 pm
by alexander38
that's one good reason to be at a good and well kept marina. I'd ball up like a baby if I seen that stuff hanging from my boat. :cry:

Posted: Mon Jun 07, 2010 8:42 pm
by foofer b
It seemingly ate the bronze strut and rudder because they were softer than the Nibral prop and stainless shaft - but grounding may have had an effect as well - since the prop shows NO signs of erosion.




Look again, the prop is totaled too. It's riddled with holes like worms have eaten o it.

Posted: Mon Jun 07, 2010 8:44 pm
by foofer b
They are just lucky it did not sink, or totally destroy the bottom what with those shafts hanging.

Posted: Tue Jun 08, 2010 1:01 am
by rossjo
Right - The nickel in the Nibral prop saved it a bit compared to the bronze strut - and the stainless shaft would be last to go.

Still amazing how much current must have been going through them to go that bad in such a short time.

Posted: Tue Jun 08, 2010 4:37 am
by alexander38
Jamie, Don't drop this we all want to know why this happened.. :shock:

Posted: Tue Jun 08, 2010 5:17 am
by k9th
Wow what a mess that is. It would seem that if it happened to this guy it would happen to others in the marina also if it was a marina problem. That is some serious current going through that equipment.

The engineer in me says that the overall current draw should be able to be calculated based on the materials and the rate of deterioration due to electrolysis. That might give someone a clue of where to begin to look.

Posted: Tue Jun 08, 2010 6:35 pm
by Stripermann2
alexander38 wrote:Jamie, Don't drop this we all want to know why this happened.. :shock:
I won't. When I find out more, I'll report.

Sad thing is that I heard the new owner has very little money and is looking to get the cash up to repair her.

It can get expensive to be broke...I can sometimes relate! :wink:

Posted: Tue Jun 08, 2010 7:07 pm
by bobg
I would tend to suspect a grounding problem on the boat itself rather than the marina. But if there is a marina problem it should be detectable. Put a voltmeter from the water to a solid ground on the dock such as the breaker panel.

A common cause of death in marinas is swimmers around boats with grounding problems introducing high voltages into the water from the AC system.

Posted: Sat Jun 12, 2010 3:45 pm
by Danny Bailey
I agree. There is a ground corroded off somewhere on that boat that is causing all the return current to travel through water via the underwater hardware. I would not be surprised to find a 12v positive wire attached to the bonding system somewhere.