[Sentoa] Corrosion question

kolomoku kolomoku03 at earthlink.net
Thu Oct 21 23:46:00 EDT 2004


First, you should not have stainless in contact with aluminum.  You
need to have some sort of insulator in between to prevent galvanic
corrosion.  This can be an insulating washer or such and should solve
the problem, especially where they meet.

Tom Stoebe
NT 077 Kolomoku

>>
>> ----------------------------------------------------------------------
>>
>> Message: 1
>> Date: Mon, 18 Oct 2004 11:43:34 -0400
>> From: "Paul Weakley" <jweakley at visi.net>
>> Subject: [Sentoa] Corrosion
>> To: "Sentoa" <sentoa at lists.samurai.com>
>> Message-ID: <NDBBJJFHILLGEGBOEBOGEEFGDPAA.jweakley at visi.net>
>> Content-Type: text/plain; charset="Windows-1252"
>>
>> Hi Tuggers,
>>
>> I have a problem on my  NT 32-207 "ABACUS".  Yesterday I was checking
>> the
>> fluid level in my batteries and I noticed a gray dust on the carpet
>> in my
>> engine room.  The gray dust turned out to be from the autopilot pump
>> which
>> is mounted next to the starting battery on the starboard side.  This
>> pump
>> consists of an electric motor connected to an aluminum block which
>> has three
>> hydraulic hoses connected to it between the wheel and the piston at
>> the
>> rudder.  The motor has only a red and a black wire connected to it.
>> There
>> is no green ground wire attached to any part of the pump.  The
>> aluminum
>> block is fastened to the hull with two stainless steel screws and
>> washers.
>> I presume the pump reversing mechanism is at the autopilot device at
>> the
>> helm.  Therefore a ground wire is probably not appropriate for the
>> autopilot
>> to function properly.  My problem is the aluminum block is corroding
>> away.
>> I believe the Raymarine autopilot was installed by the dealer or the
>> first
>> owner.  How can I stop this corrosion of the pump body.  If it
>> continues
>> much longer I'm sure it will eat through the pump body, resulting in
>> a loss
>> of the autopilot at best and loss of steering completely at worst.
>> Any
>> ideas of how to stop this corrosion from continuing and how to
>> clean/repair
>> the pump body.  Any help will be greatly appreciated.
>>
>> Paul Weakley
>> ABACUS  NT 32-207
>> 208 Packets Court, Ste. C
>> Williamsburg, VA  23185-5629
>> 757-229-6035 Office
>> 757-229-3461 Fax
>> 757-20-8231 Home
>>
>>
>>
>>
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>>
>> End of Sentoa Digest, Vol 16, Issue 16
>> **************************************
>>
>>
> Tom Stoebe
> 425-451-7812; Cell 415-890-4652
> FAX 206-543-3100
> tgstoebe at earthlink.net
>






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