Rolf, I have been looking into this for quite some time. I can't say that
I've made all the best decisions, but I ended up with both a laptop and a
min-itx computer.

If power consumption is your primary concern, mini-itx is the way to go.
They are single board computers with a max processor speed of 1 gig,
actually I think the new ones may be up to 1.2 gig. Mine is a 900mhz and it
does every think you have mentioned quite adequately. I run Nobel Tec VNS
on it, watch movies and use MS Office. You can power supplies for them that
will take any voltage between 11 and 36 volts and wire it directly to your
12v system. You will still need a dc-dc converter/regulator for the
monitor, but they are available as well. Most 12v electronics cannot be run
directly from your 12v system, the voltages vary too much. Here are a few
sources:

Converters for most laptops and many monitors:
http://lindelectronics.com/

for itx stuff try http://www.logicsupply.com/

A neat little power calculator: Power Simulator
http://www.mini-box.com/core/media/m...32 e&_xt=.htm




If you go the laptop route, I would recommend a Pentium M Centrino system as
they use less power. Look for one of the new bright displays, HighBright
XBright etc.



"Rolf" wrote in message
oups.com...
Sorry this topic has been discussed in many forms before.
I need a computer for the boat which I am going to buy ( 45 to 50 ft
cruising sailboat). I initially considered a desktop but was scared off
by the power consumption.
Now I am considering a Laptop. I want to use it to run navigation and
other boat soft ware, but I also want to use it for e-mails and for web
surfing when I have access and also to watch DVD's and CD's, so I feel
I need a Pentium 4 with Windows XP.

There is a bewildering choice of brands. One way to narrow the choice
is again power consumption from the house batteries since the computer
will be on a lot.
I can get an inverter and then plug in the power supply to that. But
that route looses about 20% of the power.
The better option is to have a DC to DC converter like one that is used
to connect a Laptop to the cigarette lighter in a car. But how much
power does that consume?
Third choice, is there a brand of Laptop eg Toshiba or others which
accepts power stratight from the House battery, ie a voltage anywhere
between 10 and 15 volts?