[C38] why not unplug when leaving boat?

[D. R. Strong]

We are at the large Emery Cove marina in SF Bay. My marina manager told 
me that all of the fires that have started during her 10 year or so 
tenure were due to a short at the point that the shore power cord was 
plugged into the boat.
    Another reason to unplug when leaving the boat is that the zink in a 
bronze prop can act as a sacrificial anode. In our first year of 
ownership, the key to the prop sheared and we lost an expensive 
Flex-o-Fold prop while backing. Not knowing what was going on, I 
continued to leave the boat plugged while absent from the dock. Three 
years later, the prop key sheared while motoring. We didn't lose the 
prop this time because it was driving forward, not backward. The diver 
removed it and showed me that the sheared key had deep pits, presumably 
where the zink had dissolved. The prop was also pitted. Since that 
episode, when we were lucky not to have shelled out another boat unit 
(=1k) for a new prop, I have had zinks changed every 3 months and have 
endeavored to unplug every time when leaving the boat. Since the new 
policy of unplugging, the zinks look good after 3 months. Before I 
started to unplug, they would be ravaged and not serving. I assume that 
at the point that the zinks failed, the bronze would take over and begin 
to dissolve.
    When my kids forget to unplug after one of their big party days on 
the Bay, lots of zink is now left to take the current for the week or so 
before I come back to the boat. We do not know where the current is 
coming from. A doc friend who is an engineer suggests that when plugged 
in, stray currents from other boats could arc through our boat and back 
to the cord, but he says that this is just and iffy idea. He measured 
some stray current at the plug when the boat was plugged in with every 
electrical switch on boat at off. The marina has recently upgraded the 
electricity, and this might reduce stray current; who knows. Apparently 
there are isolation devices that I could install just downstream from 
the plug, but if I unplug when leaving I don't need to do that. What I 
need to do is watch both male and female components of the plug devices 
for corrosion and or evident of excess heat.
    All suggestions appreciated.
Regards, Don

Phil Gay wrote:
>
> A friend with an Islander 36 had a fire, while on board, that started 
> from corroded wire terminals at his shore power connector.  His master 
> breaker didn't blow either.  This connector isn't hard to remove and 
> is worthy of a check every few years.
>
>  
>
> Phil  Gay
>
> C38 049 Que Linda
>
> Everett, WA
>
> *From:* listserve-bounces at catalina38.org 
> [mailto:listserve-bounces at catalina38.org] *On Behalf Of *PAUL NOTTE
> *Sent:* Saturday, December 05, 2009 7:58 AM
> *To:* Catalina 38 Listserve
> *Subject:* Re: [C38] How I almost lost our '38
>
>  
>
> There have been three serious marina fires in B.C. since it started to 
> get cold up here. Just a reminder to myself to follow through and 
> finish one job before I go on to another. I plad to have one outlet on 
> the boat one it's own circuit just for things like a heater or 
> electric kettle etc. I really would like to have to worry about air 
> conditioning and not having to keep my self warm. we still have one 
> kid at home so we won't be venturing south for at least three more years.
>
>  
>
>   Regards Paul
>
> ----- Original Message -----
> From: Max Soto <maxsoto at gmail.com>
> Date: Saturday, December 5, 2009 7:48 am
> Subject: Re: [C38] How I almost lost our '38
> To: Catalina 38 Listserve <listserve at catalina38.org>
>
> > Hi Paul,
> >
> > You are lucky that you were there on time!!
> >
> > I just installed an air conditioning unit on Estancia, and had
> > to install a
> > separate breaker, according to the last AC wire diagram from
> > catalina, the
> > AC outlets should have a separate breaker, so I installed a
> > breaker for the
> > air conditioning, another for the water heater (which I don't
> > have), and
> > another for the outlets, and left the original AC breaker as an
> > AC master
> > breaker,
> >
> > If you are talking about positive wires, I guess you are talking
> > about the
> > DC power and it also sounds very wise to separate the circuits,
> > just like
> > Les did with his light on Jace. He separated port and starboard light
> > circuits, so if one has a problem the other will still be providing
> > illumination.
> >
> > Regards,
> >
> > --
> > Max Soto
> > C38 #198 ESTANCIA
> > Puntarenas, Costa Rica
> >
> >
> > 2009/12/5 PAUL NOTTE <panotte at shaw.ca>
> >
> > >        We have owned
> > Impulse exactly one year today. One of the first
> > > things we did was to install a new shore panel with newer
> > circuit breakers,
> > > not only did it look great, it allowed me to put the hot water
> > heater and
> > > the battery on their own separate breakers. I left ALL the
> > cabin outlets on
> > > one breaker and moved on to other things I thought needed
> > attention first.
> > >     I have been trying to spend one night
> > a week on the boat , I find this
> > > gives me some time alone and being somewhat obsessive
> > compulsive I get to
> > > take things apart and put them back together,it's how I learn.
> > I have a rule
> > > that when I leave the boat I close all the sea cocks and turn
> > off the power
> > > , I think it's a good rule . On Tuesday after spending the
> > night on the boat
> > > I decided to walk up to the coffee shop and left a small
> > ceramic heater
> > > plugged in to the left side V berth outlet , when I returned
> > about an hour
> > > later I could smell burnt wiring. Following my nose it led me
> > to the head,
> > > the outlet there was warm to the touch ,did I mention the
> > breaker had not
> > > tripped. I shut off the breaker pulled out the plug and found
> > the positive
> > > wire had melted back from the plug for about two inches then
> > melted the
> > > positive wire.
> > >      I have room for three more
> > breakers in my new panel so I'm going to
> > > split up the circuits like I should have when I put in the new
> > panel and
> > > main feed. I will also follow my own rules in the future.\
> > >
> > > Paul  Impulse
> > >
> > > _______________________________________________
> > > Listserve mailing list
> > > Listserve at catalina38.org
> > > http://catalina38.org/mailman/listinfo/listserve_catalina38.org
> > >
> > >
> >
>
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>   

-- 
Donald R. Strong
Professor
Section of Evolution and Ecology
University of California Davis
95616
530 752 7886

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