On Thu, 12 Aug 2004 07:07:43 GMT, "Glen \"Wiley\" Wilson"
wrote:


What you say has a good deal of merit, IMHO.

Well, thanks...it mainly comes out of being forced to think outside of
the box (PC box?) due to the effective 300% premium of the word
"marine"...

Just to be fair and
balanced, I'll mention the two downsides I've observed. First,
daylight visibility of commonly available and reasonably priced
displays is poor.

Which is why I would NOT have the display in the sun, per se, but
mounted on a swiveling armature that is viewed in the relative shade
of the companionway. Fiddling with the text size settings can
conceivably give huge numerals that should be visible for depth
finding, say.

I would concur that if you want to see radar or densely packed charts
in your cockpit, you may need a specialty display. It needn't be
"marine", however, as there may be options from the automotive arena
or the sort of displays used by paramedics in the field and so on. Or
a simple hood with Velcro strips to block extraneous light.


Second, when the chips are down and the seas are
high, screwing around with a mouse and standard keyboard to setup
waypoints is a bit problematical.

Yes, it is. But if you require, say, a switch between a chart plotting
display linked to the GPS providing a current position and a heads up
radar display set to 12 miles, you can click a wireless mouse at the
IR sensor in the display (add on or built in) without leaving the
wheel or tiller. That's actually easier than punching in waypoints
using most Raytheon etc. displays. I am not knocking such devices, but
merely pointing out that they command a high and perhaps unnecessary
premium (for most sailors) considering what they do and how they
display information....part of the reason many people don't want
bigger displays is, I suspect, that they don't want that windage on
the cabintop, and/or to cut that big a hole in the bulkhead, or to
clutter up the binnacle. The largish, fold away display which uses a
PC to link the various incoming depth sounder/radar/GPS signals seems
to me to be a workable compromise.


I have some thoughts about that, but
I haven't had a chance to experiment. My current approach is to keep
the standalone instruments, using the PC as a repeater. That gives me
the best of both worlds. Please excuse the blatant commercialism in
my standard sig. At least it's on topic...

Actually, it's handy to consider, as there are a few "getting all the
kids not to argue" issues with integrating all these gadgets on a PC.

The repeater idea is good, too, because you can bury the PC box
someplace safe and dry and run USB to displays and keyboards, etc. you
can pack away when not in use in the nav station drawers.

R.

On Thu, 12 Aug 2004 09:53:32 -0500, wrote:


Using desktop with batteries is a stupid thing on a small boat - it
consumes 100Watt easily, plus the LCD another 30-40Watt, since it's
bright and not designed to save power. And you cannot suspend it. Laptop
consumes 60-80W and has several levels of power saving.

Good point

And like I said earlier maybe it best to use a laptop
anyway for above reasons.

Also the economies of scale give us good deals on
laptops

I will say one thing for laptops: used ones a couple of years old are
plenty smart enough for ALL boat nav/radar/sensor jobs, and are
considerably cheaper due to the "cool" factor of the latest rigs.

A reasonably solid PIII IBM Thinkpad securely mounted to a nav
station, with a slaved display on a swiveling arm would serve in most
situations.

Handy for Floridians, for instance, when connected to wireless
Internet, to download hurricane tracks and other nerve-wracking
info...man, I don't envy you guys tonight...it's like getting squared
in the nuts, first the left one, then the right...ow!

R.

Or you can run your desktop PC on 12 volts. See link below for one
example. Search with "dc input" as one of your terms to find others. PC
Power & Cooling company offered a 12volt supply once, but I didn't see
it on there site when I glanced through it today.

http://www.orbitmicro.com/products/p...c-dc%20ps2.htm

This is not a sure fix, but it _might_ help a lot. You need to check
power consumption specs, what sort of power management controls the
supply includes (some supplies can be controlled by your software,
something like a laptop), how clean the input voltage has to be and what
RFI certification (if any) the product has - amoung other things.

By selecting your operating system and components (harddisks, CDs, DVDs,
displays, etc) carefully to find those with good power management
options, you can produce low consumption PC. Some mother boards and
power supplies provide fan controls to slow or stop the fans when the
machine hibernates. However, the process can be frustrating because: 1)
the real specs take time to locate; 2) the software and hardware
interactions can become complex - and sometimes they just don't work
like the book says they do.

But it's doable, and a little research should tell you whether you can
get 80% of the benefit by spending 20% of the effort (skip the tough
power management/software issues). Another idea would be to use laptop
harddisks. They run slower, but they use less power; AFAIK they use the
same hard disk interface protocol and I believe there are mounting kits
(with adapters for your ribbon cables) to install them in standard cases.

Dirt and cooling can be issues and they are related. This is just
standard PC stuff, but if you're not living 3 blocks from CompUSA, it
becomes more than just an annoyance when the machine takes a crap. A PC
generates heat and when things are right, cooling fans carry it away.
But the air the fans move around can contain dust and cat hair and the
like and this clogs up the fins of heat sinks, covers the fan blades,
and generally messes up the heat/cooling balance. It helps to take the
time to find all the air inlets on a PC case and cut pieces of furnace
filter material to cover them and keep (some of) the dust out of the PC.
Or mount the whole case inside a protective box with large carefully
located air holes which you cover with several layers of filter
material; seal all seams. Nothing complicated or difficult about this,
but it can save your PC. You can build machines with motherboards and
operating systems which monitor temperatures and will shut down before
the PC toasts itself, but this takes a fair amount of research and
careful software installation (but not more $$).

I use a wireless mouse and keyboard and find them a god-send. I just
throw the keybd and mouse in a slot by the display and have the table
clear - no muss with cables. Haven't got rid of the USB or printer
cables yet, but with the USB I just bring one cable up and velcro the
multiport connector to the bulkhead above the table. You could probably
install the DVD in a separate box on the table, as long as the PC is
located within about 36".

The point of all this is to keep the PC locked away safe, clean, and
cool, untouched.


Have fun. Rufus



wrote:
Im not a sailor but I have a question out of curiosity.

Is it possible to use small form factor desktops on boats with DC
systems rather than use laptops?

Bottom line.... can one use and modify a desktop to run off 12 vdc
boat system..... or is one just stuck using and buying laptops that
are already setup to use battery DC power?

And like a desktop machine, I
can take it apart and swap out components.

Exactly!

That was reason for my original post abt even using
desktops for marine/boat use

These guys offer the Shuttle case with a 12v power supply and they
coat the boards as well to give them some protection.
http://www.marinercomputers.co.uk/

Mark

Those prices are a bit high for just adding conformal coating. You can
build a really nice SS56G shuttle system equal to the 2.8 Mhz P4
"Mariner II" for about $700. They want $1,500. The heat pipe and
variable speed fan are standard features and a can of conformal coating
spray is about $6.

M A Shaw wrote:

These guys offer the Shuttle case with a 12v power supply and they
coat the boards as well to give them some protection.
http://www.marinercomputers.co.uk/

Mark

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

Those prices are a bit high for just adding conformal coating. You can
build a really nice SS56G shuttle system equal to the 2.8 Mhz P4
"Mariner II" for about $700. They want $1,500. The heat pipe and
variable speed fan are standard features and a can of conformal coating
spray is about $6.

That's even better info! Thanks!