The Fishing Website : Discussion Forums : Electrolysis https://www.fishing.net.nz/forum/ Sat, 06 Jun 2026 01:44:10 +0000 Thu, 20 Apr 2023 14:30:27 +0000 http://blogs.law.harvard.edu/tech/rss Web Wiz Forums 12.01 360 https://www.fishing.net.nz/forum/RSS_post_feed.asp?TID=21062 <![CDATA[The Fishing Website : Discussion Forums]]> https://www.fishing.net.nz/forum/forum_images/web_wiz_forums.png https://www.fishing.net.nz/forum/ <![CDATA[Electrolysis : I’m wondering if someone can...]]> https://www.fishing.net.nz/forum/forum_posts.asp?TID=21062&PID=1832837&title=electrolysis#1832837 Author: Almo1960
Subject: 21062
Posted: 20 Apr 2023 at 2:30pm

I’m wondering if someone can shed some light on this.
I have a small modern aluminium boat fitted with a Yamaha F50. When I put a multi tester between the boat & trailer I get a voltage reading of 0.17volts. Disconnect the battery and it’s still there. (Safety chain off)
Remove battery and connect tester to positive lead & boat, same reading.
Disconnect everything from distribution post, same reading.
Connect tester between negative battery terminal with battery leads connected 0.00 volts. Have I got an issue or is this small voltage (0.17 volts) acceptable? Could such a low voltage be caused by the 30 odd stainless screws holding various things in place?]]> Thu, 20 Apr 2023 14:30:27 +0000 https://www.fishing.net.nz/forum/forum_posts.asp?TID=21062&PID=1832837&title=electrolysis#1832837 <![CDATA[Electrolysis : Rockhopper wrote:As an aside,...]]> https://www.fishing.net.nz/forum/forum_posts.asp?TID=21062&PID=286546&title=electrolysis#286546 Author: MikeP
Subject: 21062
Posted: 18 Jun 2007 at 11:19pm

Originally posted by Rockhopper Rockhopper wrote:

As an aside, is a pontoon boat more bouyant if the pontoons under pressure ???
 
The opposite would be true.  More bouyant if they contained a vacuum.  However this would not be so smart as you wouldd need them to be much stronger (thus heavier) in order to withstand the vacuum, and if they developed a leak below the waterline they would suck in the seawater.
 
Regards,
Mike P
]]> Mon, 18 Jun 2007 23:19:30 +0000 https://www.fishing.net.nz/forum/forum_posts.asp?TID=21062&PID=286546&title=electrolysis#286546 <![CDATA[Electrolysis : As an aside, is a pontoon boat...]]> https://www.fishing.net.nz/forum/forum_posts.asp?TID=21062&PID=280445&title=electrolysis#280445 Author: Rockhopper
Subject: 21062
Posted: 31 May 2007 at 9:53pm

As an aside, is a pontoon boat more bouyant if the pontoons under pressure ???]]> Thu, 31 May 2007 21:53:44 +0000 https://www.fishing.net.nz/forum/forum_posts.asp?TID=21062&PID=280445&title=electrolysis#280445 <![CDATA[Electrolysis : Electroysis will occur when two...]]> https://www.fishing.net.nz/forum/forum_posts.asp?TID=21062&PID=280442&title=electrolysis#280442 Author: Rockhopper
Subject: 21062
Posted: 31 May 2007 at 9:49pm

Electroysis will occur when two dissimilar metals ( in your question ali in your boat and ali/steel of the motor) are both placed in an electrolyte (conducts electricty for the sake of argument) which in this case is salt water.
One of the metals will be more "positive" than the other and will turn to a salt under the right conditions.
The trick is to make the metal that disolves not your expensive outboard so people add zinc which are way more "positive" electrical current flows then flows from the zinc , dissolving it in the process.
 
By electrically straping it all together the electrical difference between boat and motor is removed. You have not completely removed the problem as seawater itself is a path to earth (or seabed) , the zincs will still do the same job but now the whole boat is covered.
]]> Thu, 31 May 2007 21:49:24 +0000 https://www.fishing.net.nz/forum/forum_posts.asp?TID=21062&PID=280442&title=electrolysis#280442 <![CDATA[Electrolysis : Don&#039;t you need the different...]]> https://www.fishing.net.nz/forum/forum_posts.asp?TID=21062&PID=280358&title=electrolysis#280358 Author: bustedoff
Subject: 21062
Posted: 31 May 2007 at 6:42pm

Don't you need the different metal parts to be all at the same electrical potential? I think this will stop the battery effect (electrolysis). On aircraft they do it by earthing all metal parts to the main frame.
 
Pressure testing, I reckon about 4 psi?
]]> Thu, 31 May 2007 18:42:26 +0000 https://www.fishing.net.nz/forum/forum_posts.asp?TID=21062&PID=280358&title=electrolysis#280358 <![CDATA[Electrolysis : I know its probably been covered...]]> https://www.fishing.net.nz/forum/forum_posts.asp?TID=21062&PID=279896&title=electrolysis#279896 Author: Lurcher
Subject: 21062
Posted: 30 May 2007 at 9:09am

I know its probably been covered before but....

Have almost finished assembling a 4M alloy pontoon boat. I used polyprop bushes and a piece of vibra stop pad to isolate the motor. I also isolated the steering and remotes from the hull. Using a multimeter there is no conductance between the motor, or any cable components/steering components and the hull.

All stainless bolts used to fit other components, seats, electronics brackets etc have been isolated from the alloy using bushes/shrink wrap/plastic washers  (I'm a fussy  bugger). All alloy joins that are not full-length welded will be siliconed.

Anyhow I was surprised to read on the vibra stop website that they recommended fitting an earth strap between the motor and the hull to avoid electrolysis?

What precautions or measures are people taking to avoid electrolysis in tin boats?

Also when pressure testing pontoons and a sealed floor how many psi do you use? Do you just paint some soap suds over all the welds to check for leaks?

Cheers in Advance
Lurch
]]> Wed, 30 May 2007 09:09:07 +0000 https://www.fishing.net.nz/forum/forum_posts.asp?TID=21062&PID=279896&title=electrolysis#279896