!2 Volt ground for trailable yacht

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Hi,

I have recently downsized to a trailable yacht from a keelboat and I have to
re-do the electrical system ( old one doesn't work and is such a mess, I'm
starting from scratch). On my keelboat, all the negatives from batteries and
appliances( via a negative bus bar) were routed to a negative common post
and then to ground on the engine.

On the new boat, there is no external ground as such ( outboard powered and
no through hulls below waterline). Question is, do I just run a cable from
the negative bus direct to the negative battery terminal or is there a
better way to do this?

Any help appreciated.

Andrew

 

[Matt Colie]

Andrew,
Your plan is good. But I will mention two things that I have developed
as good rules.
With a rewire, install as many too many ciruits as you can fit. If you
can make or buy panels with a good deal of open space for additional
circuits - great.
Set the system up with only one(1){uno}[ichi] solitary connection per
battery post. This will not be hard to do if you plan it, and the
amount of confusion it saves is amazing.
My trailerable can carry two batteries for cruising and has an electric
start outboard. So, I got a 3/8 brass bolt to be the negative junction
and put it near the battery switch for convenience.
Matt Colie

 

[AD]

Matt,

Did you wire the negative to the battery negative or are you using another
ground point like a thru hull?

I am planning to take all negatives to the negative bus bar and then a
single wire from the bus bar to the battery.

Andrew

Andrew,
Your plan is good. But I will mention two things that I have developed as
good rules.
With a rewire, install as many too many ciruits as you can fit. If you
can make or buy panels with a good deal of open space for additional
circuits - great.
Set the system up with only one(1){uno}[ichi] solitary connection per
battery post. This will not be hard to do if you plan it, and the amount
of confusion it saves is amazing.
My trailerable can carry two batteries for cruising and has an electric
start outboard. So, I got a 3/8 brass bolt to be the negative junction
and put it near the battery switch for convenience.
Matt Colie

Hi,

I have recently downsized to a trailable yacht from a keelboat and I have
to re-do the electrical system ( old one doesn't work and is such a mess,
I'm starting from scratch). On my keelboat, all the negatives from
batteries and appliances( via a negative bus bar) were routed to a
negative common post and then to ground on the engine.

On the new boat, there is no external ground as such ( outboard powered
and no through hulls below waterline). Question is, do I just run a cable
from the negative bus direct to the negative battery terminal or is there
a better way to do this?

Any help appreciated.

Andrew

 

[Matt Colie]

Andrew,

Your buss bar plan sounds real good.

My boat does not have any metalic through hulls at all, and it doesn't
even have keel bolts. The only through hull is for the speed/log.

The bonding ground is really to prevent electrolysis by preventing a
differential potential between fittings. With an inboard you are stuck
with metal in the water - we are not.

Matt

Matt,

Did you wire the negative to the battery negative or are you using another
ground point like a thru hull?

I am planning to take all negatives to the negative bus bar and then a
single wire from the bus bar to the battery.

Andrew

Andrew,
Your plan is good. But I will mention two things that I have developed as
good rules.
With a rewire, install as many too many ciruits as you can fit. If you
can make or buy panels with a good deal of open space for additional
circuits - great.
Set the system up with only one(1){uno}[ichi] solitary connection per
battery post. This will not be hard to do if you plan it, and the amount
of confusion it saves is amazing.
My trailerable can carry two batteries for cruising and has an electric
start outboard. So, I got a 3/8 brass bolt to be the negative junction
and put it near the battery switch for convenience.
Matt Colie

Hi,

I have recently downsized to a trailable yacht from a keelboat and I have
to re-do the electrical system ( old one doesn't work and is such a mess,
I'm starting from scratch). On my keelboat, all the negatives from
batteries and appliances( via a negative bus bar) were routed to a
negative common post and then to ground on the engine.

On the new boat, there is no external ground as such ( outboard powered
and no through hulls below waterline). Question is, do I just run a cable
from the negative bus direct to the negative battery terminal or is there
a better way to do this?

Any help appreciated.

Andrew

 

[Lynn Coffelt]

My boat does not have any metalic through hulls at all, and it doesn't

even have keel bolts. The only through hull is for the speed/log.

The bonding ground is really to prevent electrolysis by preventing a
differential potential between fittings. With an inboard you are stuck
with metal in the water - we are not.

Matt

First, I am certainly no expert in electrolysis prevention techniques,
but since there are apparently none responding, Here's my 2 cents worth:
When the outboard is in the water, there is certainly metal in the
water, and often considerable cavitation. That, along with the rudder, which
usually has an aluminum or stainless steel post is more metal. Chain plates
for shroud, back and fore stays are usually metal too? Often in or covered
with water, no? Again, no expert here.
Lynn

 

[Matt Colie]

Lynn,

You are actually completely correct. - Except that my S2 has no metal
contact water when at the rest waterplane. The chainplates are
internal, the board lift gear is lifted dry, the rudder is outboard and
has gudgeons that are on the transom and the engine is raised unless it
is running.

In seven years, my outboard (that is connected to ship's power to charge
batteries) shows no electrolysis, corrosion or cavitation damage.

If it isn't in the soup, it won't cook. Electrolysis damage is a time
and EMF (think current flow) situation. There is little time available
in the case of most outboard-trailerables, even those that live in a slip.

Matt Colie A.Sloop "Bonne Ide'e) S2-7.9 #1
Lifelong Waterman, Licensed Mariner and Pathological Sailor