Laptops at sea?

[Capt Darren]

Prior to my 08 departure, i am trying to amast as much knowledge before I head down to the Carib. One of the things that I do plan on bringing with me is my laptop. Now, i know alot of people do this. Portible computers are generally the way of the future, but i also do know their limitations. for one, water isnt exactly a good friend with a computer, nor is humidity. As well, a computer does need constant electricity to work.

So with this known, has anyone out there ran into any sorts of troubles using a laptop while out cruising about the open waters? Also, how much power will a laptop drain from your batteries? Is the humidity too much for a laptop while at sea?

[Charlie]

Hi CD:

I bought a wireless keyboard and mouse from Logitec and plan to buy a seperate monitor. From there I will keep the laptop in a dry bag with a desecant and only a few cords (for the monitor, the wireless reciever, and a wifi antenna) sticking out of the bag. I don't have any evidence that this is a good idea but it will make me feel better.

[Vasco]

Mine has been with me for the last two cruising seasons (Nov-May). No problems so far. I was surprised to see that charging the battery takes 4 amps. Also that seems to be the draw when working off the inverter. I usually charge it when I'm motoring or charging batteries via the Honda. I use a wireless mouse which is handy because I often have to be in the cockpit for a decent wifi signal and not having wires hanging from the laptop makes going up and down the companionway ladder easier. I do not use mine for navigation but do have a gps mouse for emergency and a bunch of cd charts and software. When at sea it's well protected and when going ashore it's in a backpack on my back. Just hope I don't fall out of the dink.

[Paul Elliott]

Originally Posted by Charlie

From there I will keep the laptop in a dry bag with a desecant and only a few cords (for the monitor, the wireless reciever, and a wifi antenna) sticking out of the bag.

I think there will be problems with cooling the laptop if you run it inside the bag. These things require a decent air-flow, and will overheat if the fan intake or exhaust is restricted. Also, the laptop will just be heating and recirculating the air inside the bag.

I've taken my laptop from San Francisco to Hawaii and back on two occasions, and my friend has sailed with a laptop throughout the South Pacific for several years now. Neither of us has seen any problems due to humidity. Keep the laptop down below, out of direct spray or drips, and you should be OK. My friend and I both occasionally bring the laptop into the cockpit to show DVDs in the evening, but only during dry conditions.

I have the laptop held to the chart table with velcro, and this has been good enough so far. There are more secure mounting systems, but so far so good. I doubt that it would survive a rollover, though.

Power is my biggest issue with the laptop. It will draw 5 or 6 A when being used, and somewhat less if the screen is blanked. I prefer to shut it off when not using it (email, weatherfax, route planning, watching DVDs, etc). I use a dedicated chartplotter, rather than the laptop, mainly to keep my power budget under control.

[clausont]

Originally Posted by Charlie

Hi CD:

I bought a wireless keyboard and mouse from Logitec and plan to buy a seperate monitor. From there I will keep the laptop in a dry bag with a desecant and only a few cords (for the monitor, the wireless reciever, and a wifi antenna) sticking out of the bag. I don't have any evidence that this is a good idea but it will make me feel better.

Charlie, You may consider the heat dissipation requirements of your laptop. They still generate a significant amount of heat and as an I.T Administrator of a municipality, I replace alot of laptop hard drives that die due to heat.
It seems to me that this same heat would keep the humidity eliminated during use and storing the laptop in a waterproof bag with dessicant packs may be a good alternative to operating it inside of a bag.
Just food for thought.

[SandyM]

I have used laptops on two different boats the first in conjunction with a Raymarine system the setup of which was way beyond me but made the Raymarine plotter very much easier to operate (no soft keys). The second more recent experience was on a trip last month. Linked to a portable GPS the laptop proved to be an excellent chart plotter alternative. But beware the battery drain through the inverter. Use the laptops internal battery while under sail and start the engine if it runs out. A 4 amp load is no exaggeration. Another hazard to add to your list is mechanical damage if not tied down laptops have a habit of working their way to the edge of the chart table and over the lip if you are not careful. I have not had problems with condensation but haven't felt the laptop on board when the boat is unoccupied. A backpack is essential for the dinghy ferrying it ashore.

[Capt Darren]

SandyM, thanks for the advice. That is one thing that although i didnt think about (laptop moving about the chart table), but i am sure i would of after my laptop went crashing to the deck. =)

I too am in IT, and I figure I could drop everything in my corp life here, but computers are a lifeblood for me =) So i cant exactly go without it. I do know though that operating it within a bag for a short while is fine (like check email then close it), but long time use will fry the HDD.

But on the note of laptops running 4-6 amps roughly, what is the typical energy output on a cruiser? I guess it would depend on the generator, right?

[kushka]

My son just bought a Panasonic Toughbook off Ebay.

There are some pretty good ones. Some have touch screens, wireless networking, GPS, bluetooth... Price is pretty good on the order of $400 - $500 for a pretty decent processor. Might be worth a look.

[hellosailor]

"Also, how much power will a laptop drain from your batteries? "
How long is a string? < g >

Laptop power consumption varies radically with the processor type. Look at the power brick supplied/offered for a computer, typically they are either 75W or 140-150W in size, and you can guess that a computer which needs the larger ones draws twice as much power.

The "Core Duo" CPUs will draw way less power than than any Pentium series, the Pentium4 being a desktop CPU that draws gobs or power, the PentiumM being a mobile version. Larger screens also draw lots of power.

Whatever you get, buy a "dc to dc" supply for it, so you can plug directly into the 12V power and not need an AC inverter. Using two inverters (one to make AC, the other to drop it back down for the computer) is another big power waster.

AFAIK the PowerBooks are very rugged but not particularly sealed internally against humidity. Sealing circuit boards tends to change the way they operate, so you are best off going with a decent warranty from the maker (not a third party warranty) and taking good care of it. The older Lenovo machines, the Thinkpad designs they got from IBM, have a rep for being particularly solid as well. (The new "3000" series are all new, much less expensive, no word on them yet.)

Keeping the laptop in a waterpoof Pelican case with some dessicant cannisters during prolonged non-use would be good, but then again, you can't use the computer when it is like that.< g > Whatever you get, if you treaet it like a glass plate, don't let it bounce, don't let it get hit, that's the biggest key to longevity with them. They don't like bouncing around, or salt spray of any kind. No matter how well they are sealed.

Of course one option is to buy a cheap one, and just replace it when needed. Or, to buy two cheaper used ones--and have your own "hot spare" at hand. It can be cheaper than some 4-year warranty options on new ones.

[slomotion]

Based on my experience the Bahamas/Caribbean is a very harsh environment for laptops. I recommend you buy a bottom of the line machine and only if you are going to be in places where back and forth shipping is realistic, pay extra for the 'no matter what happens you have to give me a new one' warranty. Otherwise, simply think of these as disposable devices which have to be replaced every year or two. Backup/archive to CD/DVD or other media often. We used a RAID 1 NAS device.

Unless they have fixed their notoriously glitchy keyboards, do not buy a Dell for extended liveaboard cruising. No matter what laptop you buy, immediately create a Windows installation CD - or buy one if you have to. If you don't do this, there may come a time when your only recovery option is some clunky product-specific procedure which restores the machine to its off-the-shelf state and thereby wipes out your data files.

Also, buy a universal laptop power supply adapter- very handy for replacing the failed factory product and other uses as well. 3-6 amps should not be an issue for full time cruising - it's all a matter of your personal comfort level, but most cruisers demand substantially upgraded electrical/charging systems for other reasons and they will easily support two laptops.

There are so called heavy duty/outdoor laptops with plastic shielded keyboards, etc. Don't know that anyone has dared attach the 'marine' label to one yet. But, according to cruisers we spoke with who tried these, they are not worth the extra money and if anything are more glitch prone than more popular models. Here's the one you really want:

http://www.cruisersforum.com/forums/...1&d=1184786471

[cferger]

Howdy,

any idea of how much you would save with DC to DC option?

-chuck

Originally Posted by hellosailor

"snip

Whatever you get, buy a "dc to dc" supply for it, so you can plug directly into the 12V power and not need an AC inverter. Using two inverters (one to make AC, the other to drop it back down for the computer) is another big power waster.

[Rangiroo]

Argonaut Computers are supposedly "marinised"....I don't know anything about them except that they are damn expensive.....

Argonaut Computer - The Leader in Ruggedized Marine Computer Hardware

[Pblais]

any idea of how much you would save with DC to DC option?

At least 20% of your actual battery useage will be saved plus the amount wasted won't become heat. You can't expect more than 90% efficency when converting DC to AC and then the same back again. You can buy auto adapters for any laptop. anywhere from $30 to $90 depending. Use Google to find an adapter for the laptop and avoide buying it direct from the vendor. Then add the 12 volt outlets aboard where required. You'll find a lot of electronics will work off these. 12 volt DC devices are handy.

There is no reason to make AC electricty from DC so you can turn it back into DC again. You may need different adapters for deifferent electronics so you need to make sure you get the correct one.

Laptops really do suck in the cockpit because the display isn't bright enough. It's why the real marine displasy cost so much. Use the laptop below deck! I made straps for mine so it would stay put on the chart table. I then ran a cable from the NMEA bus and attached it to the computer serial port (or use a serial to USB adapter). You can run 3 devices off any single NMEA output. I ran one to the autopilot, one to the radar display, and one to the computer. You could get fancy and run the computer output off another serial port and then have the computer navigate too. Normally I just upload the route direct to the GPS and avoid having to rely on multiple gadgets while underway. That works for both paper and electonic charting.

[S/V Elusive]

Your large inverter (inverting from DC to AC) can be about 92% efficient (depending on load - there is a high overhead, and they aren't as efficient when used for smaller currents). Count on that really being about 80%. Then your small converters (from AC to DC) are not meant to be efficient as they don't draw much AC Current and typically aren't a factor in 'the house'. So they run about 50% efficiency. Use watts to compute and work backwards: Laptops use approximately 75 watts, which means the AC wattage will need to be about 150 watts, the DC wattage to supply 150 watts AC would be about 185 watts. When we divide by 12.5 volts we get about 15 AMPS. So, 15 amps minus (75w/12.5) = 9 amps DC saved if you go direct. Pretty damn significant ... IMHO [ummm... everyone does understand that is per HOUR - yes?]

[slomotion]

Well, I guess it depends on how you use your laptop. My Lenovo 3000 will charge from zero to 100% in 35 minutes. Then it's good for somewhere between 2 and 3 hours of use. If you have a dedicated navigation laptop, then I think the DC/DC converter is probably worth it. But, I would try to get an adjustable one - or the manufacturer's auto adapter is a good but sometimes expensive idea. Do not input 12 volts directly into a modern laptop. It might work fine for a while, but most modern laptops are designed to run on a specific input DC voltage - usually somewhere between 15-22 volts. Also, an extra battery is a good idea for cruising.