On Tue, 30 Nov 2010 05:49:55 -0800 (PST), jamesgangnc
wrote:

That will be a good test.

I am inclined to agree with some of the other posters about the amount
of electricity you seem to need. It would have been a lot simpler to
look for ways to reduce the power requirement rather than engineer a
solution to supply that much power. If you cook with propane then
what do you really need besides lights and power for the electronics?

It's really an all electric boat. It has large built-in fridges and
freezers, each with its own 110 volt compressor. Each one draws about
1 KW of power while running which is the primary demand while
underway, translating to about 100 amps at 12 volts. That power is
supplied from a 2 KW inverter when underway and we manage the load
manually by switching between the fridge and freezer every so often.
In addition to the compressors we average another 300 watts for
computers and other small electronics, so that's a steady requirement
for 100 to 130 amps at 12 volts just to supply the inverter. In
addition we have 12 volt house loads averaging about 30 amps for
things like radar, GPS units, multiple radios, auto pilot, etc. We
also have a house bank totaling about 1,000 amp-hours which supplies
the inverter at night. It needs to be recharged in the morning after
getting underway. That can easily consume another 100 amps during
the bulk stage of the recharge cycle.

In article ab125a9c-5fa3-4161-aac6-f0f346b15c92@
22g2000prx.googlegroups.com, says...
On Nov 24, 12:00*pm, Wayne.B wrote:
On Wed, 24 Nov 2010 07:20:17 -0800, Mark Borgerson





wrote:
That's a good point. *One reason for lock washers on high-grade bolts is
that they compress so you don't have to stretch the bolt.

Another reason for a lock washer is differences in thermal
expansion/contraction. * If you tighten a steel bolt against an aluminum
flange when both are hot, *the flange will contract at a different rate
than the bolt as it cools. * The aluminum will contract at almost
twice the linear rate of the steel bolt. *Conversely, tightening
the bolt when things are cool will increase the bolt tension when
both are hot as the aluminum expands more. * This is probably
a good thing----especially as it lets you work without burning
your hands! * ;-)

Balancing out all these factors is how mechanical engineers earn a
living. *The rest of us use LocTite! * (Note, LocTite may keep you
from losing the nut---it won't keep the belt tight in this application
if the thermal factors aren't accounted for.)

One thing that might help keep the belt tight is to use 60-grit
sandpaper across the adjustment arm on the side facing the aluminum
alternator flange. *WHen you tighten down the *bolt, the arm should
press some grooves into the aluminum to act as interlocking 'teeth'.

You should also be careful about overtorquing the bolt. *Depending
on the thread size, you could strip out the threads in the aluminum
flange.

Most of these issues are things you learn over the years as
you maintain your boat. *It sometimes helps to list the
issues just to make sure something isn't being overlooked.

Lots of good points there and thanks for the comments.

For now everything is about as good as it's going to get for a while.
We'll be putting some serious hours on the boat in January so I'll be
keeping an eye on everything (and carrying a spare alternator or two).

With three heavy duty belts in place I'm hoping that belt wear and
slip will not be an issue. *The old alternators were running fine on
two belts but they couldn't keep up with the electrical loads.- Hide quoted text -

- Show quoted text -

That will be a good test.

I am inclined to agree with some of the other posters about the amount
of electricity you seem to need. It would have been a lot simpler to
look for ways to reduce the power requirement rather than engineer a
solution to supply that much power. If you cook with propane then
what do you really need besides lights and power for the electronics?

Refrigeration? Air Conditioning?

Of these two, refrigeration is common even outside the tropics.

If you catch more fish than you can eat in a few days, it's handy
to be able to freeze a few day's worth. That can add significantly
to the refrigeration energy budget.

In the days when I cruised on chartered sailboats with just iceboxes,
we used to do a lot of pre-freezing and chilling to minimize ice
usage on a one-week cruise. We would pre-freeze things and keep
them frozen on the way to the charter. We once made the mistake
of putting some fruits and milk in the same cooler with some
frozen stuff over dry ice. Carbonated apples are interesting---
carbonated milk is less so.


Mark Borgerson

On Nov 30, 9:58*am, Wayne.B wrote:
On Tue, 30 Nov 2010 05:49:55 -0800 (PST), jamesgangnc

wrote:
That will be a good test.

I am inclined to agree with some of the other posters about the amount
of electricity you seem to need. *It would have been a lot simpler to
look for ways to reduce the power requirement rather than engineer a
solution to supply that much power. *If you cook with propane then
what do you really need besides lights and power for the electronics?

It's really an all electric boat. * It has large built-in fridges and
freezers, each with its own 110 volt compressor. *Each one draws about
1 KW of power while running which is the primary demand while
underway, translating to about 100 amps at 12 volts. *That power is
supplied from a 2 KW inverter when underway and we manage the load
manually by switching between the fridge and freezer every so often.
In addition to the compressors we average another 300 watts for
computers and other small electronics, so that's a steady requirement
for 100 to 130 amps at 12 volts just to supply the inverter. *In
addition we have 12 volt house loads averaging about 30 amps for
things like radar, GPS units, multiple radios, auto pilot, etc. * We
also have a house bank totaling about 1,000 amp-hours which supplies
the inverter at night. * It needs to be recharged in the morning after
getting underway. * That can easily consume another 100 amps during
the bulk stage of the recharge cycle.

How many people is it that you have to support? What's the length of
your offshore periods?

On Tue, 30 Nov 2010 08:01:15 -0800 (PST), jamesgangnc
wrote:

On Nov 30, 9:58*am, Wayne.B wrote:
On Tue, 30 Nov 2010 05:49:55 -0800 (PST), jamesgangnc

wrote:
That will be a good test.

I am inclined to agree with some of the other posters about the amount
of electricity you seem to need. *It would have been a lot simpler to
look for ways to reduce the power requirement rather than engineer a
solution to supply that much power. *If you cook with propane then
what do you really need besides lights and power for the electronics?

It's really an all electric boat. * It has large built-in fridges and
freezers, each with its own 110 volt compressor. *Each one draws about
1 KW of power while running which is the primary demand while
underway, translating to about 100 amps at 12 volts. *That power is
supplied from a 2 KW inverter when underway and we manage the load
manually by switching between the fridge and freezer every so often.
In addition to the compressors we average another 300 watts for
computers and other small electronics, so that's a steady requirement
for 100 to 130 amps at 12 volts just to supply the inverter. *In
addition we have 12 volt house loads averaging about 30 amps for
things like radar, GPS units, multiple radios, auto pilot, etc. * We
also have a house bank totaling about 1,000 amp-hours which supplies
the inverter at night. * It needs to be recharged in the morning after
getting underway. * That can easily consume another 100 amps during
the bulk stage of the recharge cycle.

How many people is it that you have to support? What's the length of
your offshore periods?

Usually it is just my wife and I. We spent the first 6 months of
this year island hopping in the Caribbean and Bahamian Out Islands.
Availability of supplies is inconsistent and expensive so we bring a
lot of frozen food from home and restock when and where we can.

On Tue, 30 Nov 2010 12:14:31 -0500, wrote:

On Tue, 30 Nov 2010 09:58:49 -0500, Wayne.B
wrote:

It has large built-in fridges and
freezers, each with its own 110 volt compressor. Each one draws about
1 KW of power while running which is the primary demand while
underway, translating to about 100 amps at 12 volts.

How old are these? My 5 year old Whirlpool side by side only pulls
about 4 amps with the lights on (a significant part of the load). Just
sitting there humming it is more like 3a.
I just pulled my KillaWatt off this PC kludge. I will reset it and put
it on the bar fridge (another full sized Whirlpool, that lives outside
in the tiki bar) that should be comparable to a boat.

These are old holding plate systems designed to run intermittently so
they have large compressors. We could probably save quite a bit of
run time if we upgraded the insulation but that would require ripping
apart a lot of custom woodwork so it's not likely to happen. The
engine room is directly below the built in fridges so a lot of heat
radiates upwards when we're making long runs, especially in the
tropics or around here in the summer time.