Att: Boat dudes needed

big2bird

Charter Member, Founder Bird-Run, Cruise-In Bird-R
Joined
Mar 5, 2008
Messages
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Location
Anaheim, Ca.
I rebuilt two dizzys for a boat with twin counter 327"s. he also installed two new marine alternators.
Well, the boat blew a bulkhead fitting for the cooling system. The coast guard pumped it out, and now it is in drydock. Just three months in the salt water with all new SS fittings, and it sank.
Coast guard says the hull is "hot." He had calcification all over the metals.
Someone e-mail me info on what we are looking for, and counter electrolysis measures please.
 
This should be right up our alley. :clap:

Could be anything from any metal being isolated from zincs to a single item (such as a receptacle or bilge pump) failing or miswired.
If docked and connected to shore power, it could be from "dirty shore power"
Literally every piece of dissimilar metal has to be bonded to ultimately sacrificial zincs.

They have a certification for this in the boating world and manuals are available for corrosion at places like West Marine.
ABYC Corrosion Certification

For dirty shore power (isolator)
http://www.yandina.com/electrolysis.htm
I've used a 3ph panel before on the dock and run the ground on the third leg. Seemed to work, but I'm no electrician.

General info
http://newboatbuilders.com/docs/CorrosionOnBoats.pdf
 
What "010752" said -- and as additional thoughts:

1. Minimize number of thru-hulls

2. Replace them with Marelon (glass reinforced plastic). The boat is probably Plastic"" anyway. [We did that to our 54ft sailboat n 2000, and have happy ever since. Pulled out a heap of "green-wire"bonding (+ weight) as well.]

3. You should check the shafts are bonded to the system as well and of course the props. Shaft bonding is easy - use a brush (electrical) attached to a heavy gauge strap of copper - bent into a spring (flat spring - just bent for tension) and bond to the ground system.

4. Have somebody do a stray current check dockside - if the slip is hot - maybe get some compensation from the marina - but I doubt it. They'll blame the neighbors - wiring - not theirs.

5. Stray current in a wet bilge (saltwater) will eat it from the inside out too.
Just my experience from living aboard our sailboat for 22 years and ocean cruising for the last 13 - Thanks for the mental break from building my trailing arms!

Cheers - Jim
 
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