In rec.boats.cruising Brian Whatcott wrote:
:On Tue, 9 Oct 2007 07:20:07 -0700, Mark Borgerson
wrote:


:You might also consider a couple of 8GB USB flash drives as backup.
:Flash memory may better accomodate the shock and vibration of
:a boat under way. When not in use, you can remove them and store
:them in a plastic bag with some dessicant.
:
:
:Mark Borgerson

:I lforgot about a memory stick in a shirt pocket I left out for
:washing.
:My wife recovered the memory stick in three pieces: two covers
:and a little card and chip. I stuck them back together. It worked.

:You could be right about USB flash robustness!

Flash is pretty resistant to temperature and most other environmental
factors, short of being hit with a hammer. Salt water might cause
corrosion to the connections to the support circuitry, though.

THANKS! For the replies; I'll summarize some of this over in the
BoatDesign.net discussion.

- Salt air, Humidity - Plans now are 12 watt system board in
sealed/gasketed aluminum box. Anti-corrosion insert, humidity control
insert. Heat transfer to 2 square feet or so of box surface to cabin
air. Need a maximum inside-cabin temperature to do the numbers.

- The 2.2 Gb and 3088 files is great data.. thanks! This fits with my
experience, no problem for 60 Gb 1.8" notebook type drive using 1
watt.

On Oct 9, 3:24 am, " wrote:
....
QUESTION1: How HOT does it really get INSIDE the cabin of a Cruising
Boat, in the Tropics? What's the typical you've experienced? What's
the worst-case??

Worst case, say Kanton in the summer, I've seen high 90's inside the
pilot house. That isn't normal. We typically see mid to upper 80's
inside in the summer in the high tropics (eg. Hawaii or New Cal) and
upper 80's to low 90's in summer on the equator.


QUESTION2: If you use computer-based charts on a laptop or other
onboard computer, how much Harddrive space do your charts take up??

Transis and C-Map cover the whole world in vector on 2 CDs or one
DVD.

Let me add, just by the way, that I don't think there is any
noticeable difference between MTBF for laptops used on cruising boats
and laptops used on land. I wonder if you're stressing more than you
have to over all this...

-- Tom.

As an aside, nearly all cruising boats that I meet have a laptop
aboard.

Bear in mind that with a video output to a monitor and a wireless
keyboard/mouse (or even wired) you get the advantages of the laptop (power
management, size) while still being able to use it as a normal PC.

When you go with a built-in system you're painting yourself into a corner.
Getting parts is bad enough in the islands, getting parts for specialized or
industrial stuff will be even worse.

Chart plotter and most general purpose use doesn't really require much
computational horsepower. It's often more economical to just buy TWO
low-end laptops; keeping one as a spare. Set one of them up, clone the
drive onto the other one and stow it safely away. Rotate it out now and
then to make sure the spare still works OK.

-Bill Kearney

QUESTION1: How HOT does it really get INSIDE the cabin of a Cruising
Boat, in the Tropics? What's the typical you've experienced? What's
the worst-case??

I write this from my sailboat in Puerto Vallarta, MX, where we have
been all summer and the average temp is mid 90's every day.

My perspective is that every boat down here which has people on it
right now, has air conditioning. So my current interior temp is 74
degrees.

In December it will cool down into the 70's here, many boats and
people will come who don't have ac, but the temp is still in the 70's.

As someone mentioned above, the hottest time is when you are underway,
running your engine because there is no breeze (most of the time
here). But most of that heat goes right up the companion way.

Most people here have normal laptops, and they all work fine. I agree
that unless you are taking yours out into the cockpit where rain/salt/
sun can get to it, you should have no additional issues.

-Mark
http://GoReads.com

On Oct 9, 8:24 am, " wrote:
Hello! This is related to a discussion over at:http://www.boatdesign.net/forums/showthread.php?t=19458

We are trying to figure out some requirements for a "Multi Purpose
Onboard Computer System".

QUESTION1: How HOT does it really get INSIDE the cabin of a Cruising
Boat, in the Tropics? What's the typical you've experienced? What's
the worst-case??

QUESTION2: If you use computer-based charts on a laptop or other
onboard computer, how much Harddrive space do your charts take up??
(Let's say for a passage, or your typical cruising area)?? How large a
hard drive do you feel you need to be "comfortable" for charts and
your other uses??

Thanks! Please answer here or at the discussion thread on
BoatDesign.net
__________________
Regards, Terry King ...On the South China Sea, in Shekou


My experience on a boat in the tropics is simply that it does not get
any hotter than summer at home without air-conditioning. Actually, in
most cases, not uncomfortable at all. As for the computer, any laptop
is more than able to handle it. Unless you get a laptop manufactured
to military specs (Panasonic Toughbook $$$), figure on replacing it
every few years (but then you'd probably replace it every few years
anyway!) Keep all your charts and other important programs on disk
and keep a system recovery/backup disk as well.

Keep all your charts and other important programs on disk
and keep a system recovery/backup disk as well.

Most folks probably know this, but just in case ... The "system recovery"
disks that come with most notebook computers today (on a CD or in a hidden
partition of the hard drive) wipe out all your data, along with any programs
you installed after you got the machine. They are designed to do that, in
order to return your machine to the way it came to you from the
manufacturer.

What you really want is a utility that will restore your system after a
crash to the way it was the day before the crash. Two that do that are
Norton Ghost (good but a bit awkward to use) from Symantec.com, and Acronis
True Image, much more user-friendly, from Acronis.com. Both retail for under
$50, and are often discounted.

I use Acronis, and make weekly compressed backups of my C: drive onto
external hard drives. I've used it to restore onto a new, bare hard drive
after a disk crash. The entire process took less than 20 minutes and gave me
a computer that was identical to the pre-crash system.

Given the importance of a navigation computer to a cruiser, it makes sense
to have a current "image backup" of the hard drive that can be used to
quickly restore the computer so all applications, charts, etc., are
immediately available.

Oh yeah -- and test the backups! (g)

Alex

On 2007-10-15 20:19:47 -0400, "Alex"
said:

Given the importance of a navigation computer to a cruiser, it makes
sense to have a current "image backup" of the hard drive that can be
used to quickly restore the computer so all applications, charts, etc.,
are immediately available.

Oh yeah -- and test the backups! (g)

Even better, "mirror" the internal drive so you can BOOT from the
backup! And do it periodically, spot-checking recent files and
programs. Our Mac will synchronize the external to match the 30 gigs of
internal data in about half an hour. I expect Windows will do about the
same thing.

Then put the backup in a electronically and magnetically shielded,
water-tight, air-tight container.

(says one who lost almost all of 20 years' files despite a image drive
and incremental backups. All failed in the same week -- a friend's
power surges took out two of them as I tried to get his back up.)

--
Jere Lull
Tanzer 28 #4 out of Tolchester, MD
Xan's pages: http://web.mac.com/jerelull/iWeb/Xan/
Our BVI trips & tips: http://homepage.mac.com/jerelull/BVI/

"Jere Lull" wrote in message
news:2007101522343316807-jerelull@maccom...
On 2007-10-15 20:19:47 -0400, "Alex"
said:

Given the importance of a navigation computer to a cruiser, it makes
sense to have a current "image backup" of the hard drive that can be used
to quickly restore the computer so all applications, charts, etc., are
immediately available.

Oh yeah -- and test the backups! (g)

Even better, "mirror" the internal drive so you can BOOT from the backup!
And do it periodically, spot-checking recent files and programs. Our Mac
will synchronize the external to match the 30 gigs of internal data in
about half an hour. I expect Windows will do about the same thing.

To my knowledge, a Windows PC won't boot from an external hard drive. It
will boot from an internal CD or DVD, but I don't think it will recognize a
USB or FireWire remote drive. I believe a Mac will boot from an external
drive, further proof that Macs are for wimps and people who want to get work
done, while Windows machines are for us macho geeks who enjoy pointless,
frustrating challenges. (g)

With a Windows system, one could create a bootable external drive with the
intention of swapping it for the internal drive in the event of a failure.
In a desktop machine it's relatively easy to pop the cables and install a
mirrored hard drive, making that the boot drive. But in a laptop, at sea in
the cabin of a pitching boat, that kind of surgery could be a bit dicey.

Alex

On Tue, 16 Oct 2007 06:05:28 +0000, Alex wrote:


To my knowledge, a Windows PC won't boot from an external hard drive. It
will boot from an internal CD or DVD, but I don't think it will
recognize a USB or FireWire remote drive. I believe a Mac will boot from
an external drive, further proof that Macs are for wimps and people who
want to get work done, while Windows machines are for us macho geeks who
enjoy pointless, frustrating challenges. (g)


Seeing that you enjoy frustrating challenges, you *might* be able to boot Windows from an
external drive using Grub, or a Super Grub disk. While I don't have much use for Windows,
grub will allow chainloading, allowing you to move Windows bootloader from the MBR to
another partition, or even another hard drive. Hey, it might be a frustrating challenge, or it
might work. :-) Some information on how other OSs do it:

https://help.ubuntu.com/community/BootFromUSB

http://users.bigpond.net.au/hermanzo...bDiskPage.html