Computers and
electronic equipment
on a boat.
         Please send any comments to me.

This page updated: August 2014

Marilee Shaffer's rules of using a computer on board:
  1. No splashes/spills on it.
  2. Run it fairly often.
  3. Strap it down.
  4. Have a good, clean power source.

Marinized computers:
From JM Cook on Cruising World message board:
Getting a 'marinized' computer is completely unnecessary. ... other than tossing it in the ocean or pouring salt water directly over it, NO protection is needed. ...

From Bob Taylor on the WorldCruising mailing list:
... I will not purchase a "ruggedized" unit. I have talked to a number of friends who have years of experience with the standard laptop models and their comment was: They will become outdated and be replaced with a newer unit before they will die. This assumes you take proper care of them which I will. In my case I will buy one of the Pelican waterproof carry cases since I will be carrying the unit in the dinghy often. ...

From Brad Geres on the WorldCruising mailing list:
... We store our 'puter (while still warm from use) in [a Pelican case] we've modified by replacing the pluck-foam with pads made by loosely stuffing vermiculite in old nylon stockings. The vermiculite draws any remaining moisture out of the case. Incidentally, we store our old Plath sextant and the stopwatch in an identical case. ...

My first experience:
My first laptop was 3 years old when I bought it, and started dying after another 2.5 years aboard. Other than old-age-related problems (the laptop's old age, not mine), the only boat-related problem was corrosion on the connector from the internal CMOS battery to the motherboard. Unfortunately, this was just about impossible to fix, since it's a tiny, surface-mounted connector, and the corrosion was on both parts.

This may have been aggravated by the way I was using the computer: I removed the main laptop battery (it was dying anyway), connected the laptop to boat's batteries, and only turned on the power when I wanted to use the laptop. I think this let the CMOS battery run down a bit, and that probably accelerated the corrosion.

My second experience:
My second laptop was new. The keyboard started dying after 2 years aboard. The DC-to-DC power converter tended to melt it's cigarette-plug connector when charging heavily for more than 15 minutes or so.

The replacement keyboard died about 2.5 years later.

Things you want in a marinized computer:

Several people say: Panasonic Toughbook is good.
Some say: Ocean PC is bad.

From Adam Chorley:
I'm an electronics technician, and have noticed people bringing me their VHF radios with WD-40 inside the case - obviously trying to stem the corrosion issue. This is a big no-no. What I have done with all my electronics (including those I service for marine use) is apply a coating of MILSPEC "conformal coating" to the PC board (both sides) after using silicon [silicone ?] to glue all parts that are susceptible to movement/vibration. I did this with a portable VHF radio (non-weatherproof) I have had on 3 different boats for over eight years - it is still as good as new. You can source this stuff from any electronics store, but I would recommend application only by qualified people.

STO.P's "Computer Hardware in the Marine Environment"

Laptop versus desktop:

From JM Cook on Cruising World message board:
If you can avoid a laptop in favor of a desktop, do it ... Laptops are difficult to repair ... A desktop, on the other hand, and especially a clone, will be easily repairable and upgradeable for the next 5 years plus you'll be able to find pieces from here to Bangkok.

But from Russell on Cruising World message board:
Laptops consume less of two things that are in short supply on many boats: space and power. They have a third advantage. Laptops are designed, more than desktops, to work under motion, and even to take hard knocks. The disks are cushioned, the connections more secure, etc. ... [And they're portable, to shore.]

From Bob Taylor on the WorldCruising mailing list:
... The desktop I use I built. It is generic parts so I have a chance of finding parts when in out of the way places. One of the problems sited with laptops is their parts are special and sometimes hard to find. ...

From Douglas Sterrett on the WorldCruising mailing list:
... The main reasons I am going to install a desktop system are increased hard drive capacity, expandability, and upgradability. With a laptop you are pretty much stuck with what comes with the machine. ...

From Glenn Duncan on Cruising World message board:
... a modern TV and VCR will require only about 120-150 watts AC; less than a desktop computer, which will typically need around 275-300 watts. (One caveat: charging the capacitors in the monitor on startup takes the most grunt. Turn it on first; 20 seconds later turn on the CPU.)

The laptop I use at work runs hot. That can't be a good sign of long-term reliability.

From letter from Luc Callebaut and Jackie Lee in 6/2000 issue of Seven Seas Cruising Association bulletin:
1) laptops, new or old, do not last in the salt air environment!
2) every time it needs to be fixed you will hear: "we need the parts, we have to order them at high cost and it will take a long time" or "it's an older model, I don't know if we can find the parts any more and laptops don't take standard parts!" ...

[so they bought 3 cheap, used, identical 486 laptops and vacuum-sealed 2 of them to use for spare parts]

Factors to compare:
Laptops are good: Laptops are bad:

Display of my Dell Inspiron 1100 laptop generates RFI that I can hear in the shortwave radio. During booting, I can hear the RFI go away when the display is blanked and come back when the display is lit again. RFI goes away if laptop is unplugged from power converter that connects it to house batteries.

Power supply:
Can't directly connect a [desktop] computer to the 12V DC power in the boat. The 12V DC is not clean enough, and the computer uses other voltages such as +/-5V DC and -12V DC.

Can directly connect a laptop. Might want to condition the power; see STO-P's "Using DC Power Fault Protectors", or just search the Web for "laptop power adapter" and look at ones for automobiles. Could get surges, especially when starting engine.

From Todd Dunn on Cruising World message board,
Your computer runs on both 12 and 5 VDC. You can convert any computer to a 12 volt source by ripping out the AC power supply (really just a multi-tap transformer with a couple of voltage regulators) and replacing it with a couple of DC to DC converters - one 12 volt to 5 volt and one 12 volt to 12 volt. I suggest using two converters because DC to DC converters have very stable voltage outputs - i.e., the 12 volt output of a 12 volt to 12 volt converter will stay at 12 volts independent of the inpout voltage as long as the input voltage stays within the converter's specs. A couple of good, reasonably high output converters will set you back a couple of hundred dollars, but they will solve your power problems. They are also small enough that you can simply put them inside the computer box where the AC power supply was.

Check out MajorPower.Com's DC/DC Converters or go to any good electronics/electrical equipment supply house.

From Anthony Powell on WorldCruising mailing list:
I asked the list a year or so ago about powering a 24v laptop with 12v. The answer was to just wire it up to the 12V. It seems that all the CPU needs is 3v and the rest is for the charging of the laptop battery.

From Jim Donohue on newsgroup:
1. Does the laptop have an adapter for 12 volt usage?

The answer is of course yes. If the company does not make one there is one available. I know of no low-power device that cannot run on 12 volts with an adapter.

2. Will the laptop run off 12 volts without an adapter?

For many of the laptops the answer is yes. My somewhat elderly Acer runs fine off 12 volts. I suspect that many laptops will, in fact, run off 12 volts - even if their manufacturer does not agree.

3 Will my laptop run off 12 volts and charge its batteries without an adapter?

Now the answer is likely no. Most of the laptops require some higher voltage and control circuitry to both operate the laptop and charge the battery. You may well be able to run the laptop but the battery is not charged at all or only partially charged.

From Glenn Duncan on Cruising World message board,
... you may find your laptop will work directly off the 12 VDC onboard. We've been running two laptops (an IBM Thinkpad and a older Compaq) directly off 12V for almost two years with no problems.

The important thing is the voltage of the laptop's battery, NOT the output of the AC adapter. My IBM, for example, uses an 18V adapter, but the battery is 9.6V. The differential is needed to charge the battery but not to run the laptop. I remove the battery and run directly from 12V.

Because I worried about voltage spikes during engine start (as the alernator comes on line) I avoid starting up when either laptop is connected. I also put MOVs (those "Protect Your Engine Computer During Jump Starts" gadgets from auto accessories shops) across the power leads for each computer.

As it happens, I've screwed up a few times and started up while the Compaq was working without any problem. MOV or blind luck or over-caution? Who knows?

Voltage converter to run a laptop from the 12V battery, rather than the inverter:
Generally called DC/DC converters or adapters, or auto laptop power adapters, on the web.

"Step-down" converters go from 12V to lower DC voltages, and are fairly cheap ($25 at Radio Shack). "Step-up" converters go from 12V to higher DC voltages, and are more expensive ($50 to $100 or more). A third option is a small inverter that plugs into a 12V socket and produces AC.

N4UAU Voltage Booster ($68 fully assembled, but web site is gone)
"Auto / Airline Adapters" from Lind Electronics
Hosfelt Electronics (800-524-6464; maybe part 40-212 $50)

Caution: charging my laptop's battery pushed my DC-DC converter so hard that it's cigarette-lighter plug melted ! This is a plug that came as part of the DC-DC converter; obviously it wasn't rated for as much current as the converter can draw.

From Mark Melvin on the WorldCruising mailing list 12/2000:
PC's have a special power supply that takes in AC current and puts out very carefully managed +/-12VDC, +/-5 VDC, and +3.3VDC on newer "ATX" style motherboards (which are almost all of them made in the past 3-4 years except for homebuilts. Older motherboards are "AT" style). Fluctuations in the output voltages are fatal to CPUs and hard drives, so building your own is _NOT_ a good idea, to do all the proper rectification the parts would cost you more than an assembled unit.

Most DC laptop adapters (car adapters) that run a laptop from the cigarette lighter of a car take in 12VDC, turn it into 120VAC to feed the laptop's built in AC->DC power supply. Horribly inefficient but most people don't realize that. Some DC laptop adapters do bypass the DC->AC and feed their DC to the the rectification side of the laptop's internal supply, but those are rare and not as stable; the laptops used with them tend to end up with lower battery life if used long term because the rectification circuit is starting with a lower DC voltage than the AC->DC supply would have generated.

The regular PC (not laptop) AC->DC power supply modules are easy and cheap ($20) to replace with new AC->DC power supplies, but what you're talking about is a DC->DC power supply.

Many companies make these, but you're not going to find them in CompUSA or Radio Shack, you need an industrial supplier (e.g. Sinetic).

From Rufus Laggren on The Live-Aboard List, 10/2002:
PC Power & Cooling came out recently with a supply for standard PC's that runs entirely off 12 volts. I believe it's 250 watts max.

It used to be the case that the refrigerator/freezer was by far the biggest power-hog on DC-based boats. But running a computer can take more power than running the refrigerator ! And recharging a low-battery laptop will take even more. And the refrigerator typically runs about a 50% duty-cycle; the computer generally runs at 100% while you're using it.

Conversion efficiency of those small "wall wart" or "brick" AC adapters can be as low as 1/3; they can waste 2/3 of the power. And they consume some power even when no device is plugged into the DC side. Add the losses in your DC-AC inverter, and the "battery DC to inverter to AC to brick to DC to device" chain can be very inefficient.

Peripherals (printer, scanner, etc):
Useful to have scanner and printer (instead of a photocopier), to make copies of crew lists, passports, etc.

Many peripherals can be powered from the USB cable, instead of a separate power supply. USB-powered floppy drives, CD drives, scanners, Wi-Fi adapters are available. But few printers ! Some peripherals draw too much current from the USB port: my USB DVD drive causes "USB device has tried to draw too much current" errors on my old Dell laptop.

USB supplies 5 VDC, from 100 MA to 500 MA per port.

Some battery-powered mobile printers are available. But it's very hard to find out what DC voltage popular printers require; the printer companies just don't think in those terms. HP inkjets seem to require both 20 and 36 volts DC. Most Lexmark printers require 30 volts DC.

From JeffeeB on Cruising World message board:
In general you need at least 1000 W of available capacity to run a laser printer.

Idling a (modern) laser printer draws very little, in fact many of them will automatically "sleep". When actually printing, a laser printer takes a good amount of juice. But most importantly, there is a very big surge when the first page in a print job arrives: all the motors spin up, the laser comes on, and it begins to heat up the fuser roller to several hundred degrees, before the first sheet of paper gets to that roller.

From Mark Mech on The Live-Aboard List:
[Re: printer that will run on a battery pack and is made especially for use with a laptop:]

I thoroughly checked out portable printers for the boat, but ended up getting a standard HP color printer due to operating costs. The new HP's have a paper tray that folds and you can refill the cartridges for about $5.

The micro Canon has very small, very expensive cartridges and also needs new print heads every few cartridges. The operating costs are very high; you could buy a $45 inverter to run the standard printer and it is about the size of a large toaster when folded. The power supply is 18v @ 1 amp so that's only 18 watts; the smallest inverter would run it.

From Rob Hepler on The Live-Aboard List:
If footprint isn't a concern, 'regular' office-type inkjets are dead cheap. Some months ago I bought a refurbished Lexmark for $40 with a $20 rebate. That makes it cheaper to buy new printers than new cartridges. All Lexmark printers I have looked at do *excellent* text. At that price, a $40 inverter to power it is still a bargain. Especially if it powers the blender, too :-) I also got a free Lexmark (different model) with a computer bought from Dell. Haven't even taken it out of the box yet; it's the backup for the $20 model.

Use household/commercial/industrial stuff rather than marine $tuff; it will last longer than you think (especially in my dry trimaran) and is LOTS cheaper.

From Chuck and Linda 7/2009:
"I like the Canon IP-90 which we have been using for the past 6 years. Small and always works great."

From someone:
"Epson and newly HP have 'waterproof' ink; I switched for Epson and the ink is much better."

From Susan on the IRBS live-aboard mailing list:
Re: Is it practical to use charting software on one's laptop while cruising ?

We tried a system and found it completely impractical for our boat. There wasn't any good place to put the laptop in the cockpit and we couldn't see the screen due to sun, glare or position of the helmsperson.

We put the 'puter down below and wore ourselves out running up and down to check our position. It wasn't long before we realized we were checking our paper charts, completely ignoring the computer running in the cabin.

Computers and water don't mix well: pic.

Summarized from Captn. Jack's "CRT monitors on board":
CRT's generate significant magnetic fields that can affect compasses and other instruments; LCD's don't.

Summarized from Captn. Jack's "Screen brightness":
Computer display brightness: want daylight-friendly (200-1000 nits) or sunlight-readable (1000+ nits).

Low-Cost Windows Software:
Equivalents of Microsoft Office ($250+):

Best free software, from 12/2005 issue of PC World magazine:
Lower-cost replacement for Intuit's Quicken: MoneyDance.

Free software if you're connected to the Internet:
Google Docs and Spreadsheets (saves to HTML, Word, etc, on server or on your disk)

My original experience:
I use a laptop on my boat, and never connect it to the internet. I use floppy disks to copy files between my laptop and computers ashore (in libraries or internet cafes). This works well except that:

My later experience:
I use a laptop on my boat, and use Wi-Fi to connect it to the internet (taking the laptop ashore to an internet cafe, or sometimes getting a Wi-Fi signal right from the boat). This works well except that:
Later, I bought a Blueproton GSky Wi-Fi adapter, and am very happy with it. May not be the best, but seems very good and was cheap, and the simple fact that it is at the end of a 4-foot USB cable instead of being attached to the side of the laptop makes it much more effective than my old 3Com card-adapter. But it does not work with a USB-extender cable; limited to the built-in 4-foot cable.

Still later: a number of those Blueproton GSky Wi-Fi adapters have died on me, one from being dropped, another maybe because of heat. Switched to a Rosewill adapter. It also runs hotter than I'd like.

How to repair a scratched CD-ROM (from Ideas of the Week Newsletter from Idea Exchange):
  1. Get a clean, soft cloth and wipe the disc from the center outward with straight spoke-like strokes. Do NOT wipe the CD in circles; this will cause more scratches.
  2. Next squeeze a miniscule amount of toothpaste onto the scratch. With another soft, clean cloth, rub the toothpaste into the scratch and then remove any excess.
  3. Polish the CD with a chamois cloth and any petroleum-based polishing solution -- Armor-All, clear shoe polish, or Vaseline. Wipe in straight lines from the inside out.
  4. Finally, squirt a drop of Windex or another water-based window cleaner on to the CD and wipe with yet another clean cloth.
Does not work with CD-RW's, only CD-ROM's ?

From Bob Hardin on the Yacht-L mailing list:
Many liveaboards report that CDs absorb moisture at the outside and inside edge. The causes them to corrode and become worthless. They seal the edges with nail polish and other such things. Seems the edges are just cut out and not sealed.

From Bob Stewart on The Live-Aboard List:
One of the brightest, low cost, office lcd monitors is the CMV CT-522A 15" LCD Monitor w/Speakers. It has a brightness number of 450 cd/m2 and I've heard of cruisers using this model under dodgers and in the companionway. This does run off 12 volts.

Wet electronics:

From "How-To: Recover from a Soda-Spill Disaster" by Alex Castle:
  1. Act fast; don't sit around moaning about it.
  2. Maybe turn device upside down, to stop further penetration.
  3. Turn it off / unplug it.
  4. Remove batteries.
  5. Assess the damage.
  6. Wipe up.
  7. If needed, disassemble the device. Maybe take pictures as you do so.
  8. Wash it off. Maybe with alcohol swabs. If large area is soaked, run it under soapy water, then rinse with water (distilled best), then dry with fan or gentle hair-dryer or just air-dry.
  9. When completely dry, re-assemble.
  10. See if it works.

From "Low-Tech Fixes for High-Tech Problems" article by Paul Boutin on
Batteries keep their charge longer if you keep them cool.


If you get your cell-phone (or other electronics) wet:

Take the battery out immediately, to prevent electrical short circuits from frying your phone's fragile internals. Then, wipe the phone gently with a towel, ...


Crashed Hard Drive:

If - no, make that when - your PC's hard drive crashes and can't be read, don't be too quick to throw it out. Stick it in the freezer overnight.

"The trick is a real and proven, albeit last resort, recovery technique for some kinds of otherwise-fatal hard-drive problems," writes Fred Langa on his Windows Secrets Web site. Many hard drive failures are caused by worn parts that no longer align properly, making it impossible to read data from the drive. Lowering the drive's temperature causes its metal and plastic internals to contract ever so slightly. Taking the drive out of the freezer, and returning it to room temperature can cause those parts to expand again.

That may help free up binding parts, Mr. Langa explains, or at least let a failing electrical component remain within specs long enough for you to recover your essential data.

From /u/QnA on reddit:
... you want to actively remove the moisture as quickly as possible. The longer the moisture is sitting on those circuit boards, the higher the risk of corrosion. And corrosion on electrical components can happen within just a few short hours. ...

Every time I see someone recommend rice I kinda twinge a little inside because while it does dry a phone out slightly better than just sitting on a counter, it really doesn't do much to prevent the corrosion that's going to be taking place due to the length of time the liquid has had to fester inside the phone or whatever.

What you want to do is set the item in front of a fan with constant airflow. Take the device apart as much as you can without ruining it (remove the battery, SIM, SD card, etc) so that the insides can get as much airflow as possible. Even if it's not in direct contact with the air, the steady air blowing over the device will create a mini vacuum effect and pull air from inside. It's just a small amount but it's significantly better than just allowing the rice to passively absorb the evaporated moisture. True, rice can act as a desiccant, but a fan blowing over whatever is orders of magnitude faster.

I personally will take apart a piece of electronics completely, and put those items in front of a fan, and if you have the relevant knowledge, I highly recommend doing so as well. But if you don't, it's not that big of an issue. What you want to avoid at all costs, however, is heat. Do not put your phone inside an oven or hot blow dryer, heat can damage electronics just as bad as liquid, sometimes more so. Heat, extreme cold and liquid are bad for electronics & cell phones. A fan (lots of airflow) is 99 out of 100 times better at removing moisture quickly than rice. I would say 100 out of 100 but I'm sure there's going to be some crazy situation or exception I haven't thought of that someone will come in and point out. ...

From jar311 on reddit:
If you drop and fully submerse/drench your phone in liquid:

DO NOT check your phone to see if it works, unless you want circuits to short immediately and screw yourself with zero recourse available.

DO NOT throw it in a bag of rice.

You will need:
  1. DO remove all accessories, batteries, and sim/memory cards.

  2. If your phone was dropped in sugary liquid (and ONLY if dropped in sugary liquid), completely submerge your phone in 100% rubbing alcohol (yes, I'm actually serious). You want to avoid the alcohol part if you just dropped it in water as you run the risk of dissolving adhesives inside the phone. If it was dropped in yesterday's glass of coke you'll be just as screwed if you don't do this step as your phone WILL ultimately stop functioning from the sugar residue, so the iso bath is worth the risk and SHOULD be done.

  3. Lay your phone in a bed of paper towels or dish towels in a salad spinner if possible. If you don't have a salad spinner available it's not the end of the world, skip step if needed [or use a pillowcase, whirled around]. Place phone on side against wall of spinner with screen facing the centre of the spinner, we want the liquid pulled away from the screen and towards the battery area.

  4. After a good amount of delicious centrifugal force has been applied (couple minutes, tops) in salad spinner, shake that phone like your life depended on it (keep a FIRM grip or it will end up as a decoration lodged in your drywall) until you're not getting spray out of it with each shake.

  5. Place in ziplock bag with screen facing UP with as much silica gel as possible for TWO DAYS without breaking the seal. If you have enough silica gel packets, pack the battery compartment with them and place around all sides of phone. Get as much coverage as possible. DO NOT CHECK ON IT FOR THE ENTIRE TWO DAYS. Silica is wicking moisture and we want this the entire 48 hours without interruption.

  6. While your phone is doing its drying thing, clean contacts of the sim/memory card with alcohol wipe or isopropyl and paper towel/whatever.

You want to start this process as quickly as possible, get that thing powered OFF. Circuits start blowing pretty much immediately.

While this process works well, a lot of the time previously-wet phones are still ticking time-bombs, especially if exposed to moisture while turned on (which is almost always) and left on for too long after exposure. You may notice buttons start to go, camera gets wonky, etc. That being said, I have many people who have no problems in the future at all. It's a good process and I swear by it.

And remember make this process AS FAST AS POSSIBLE.

Using alcohol probably is a bad idea, because it may dissolve adhesives and damage rubber seals.

Using a vacuum-cleaner is a bad idea, because it will generate static electricity.

Proper disposal of old electronics and batteries:
Some manufacturers have recycling or disposal programs; check with your local computer or phone store.

"Fix a man's computer, it works for a day.
Teach a man to fix his computer, and he'll call you tomorrow saying he deleted system32."

See "Theft recovery software" section of my Computer Security and Privacy page.

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