IBM 610 workstation computer 3409

The thing that really gets to the electronics is the presence of three things :

* Exposed, metallic surface (like a pc) * Corrosive agent (like salt water) * Electric potential.

When those are present you will have an electrolysis bath for your computer. Now, go exorcise the elements.

If you cannot keep them dry, put them in an otter box. Yes, really. Put a few little rolls of fresh (from a sealed roll) toilet paper in the box every time you close it up. (tip for underwater cameras). www.otterbox.com

They aren't using more than around 20W including a disk anyway, so you can close the enclosure. Use a setup where you allow any disks to spin down; i.e. all frequently accessed software on flash. Mount the card inside the box with rubber absorbers, and mount the box with the same. Consider adding 10 punds of lead sheet to the rear of the box for stability in rough seas.

Use diving attachments for the connectors. (www.hartenberger.de and alcatel have very good hullconnectors).

You may want to put "sacrificial" USB and ethernet hubs at the outside, and have some spares. Such spares should be kept in ziplock bags at all time until use. Otherwise you need to make the cabling permanent. Remember to DC power these devices as well, and have a common negative for everything. If you really wany reliable ethernet, use fiber optics.

Use proper outdoor cabling for everything outside the box. Alcatel^w Nexans has a huge catalog of this stuff. The ethernet cable is a notorious source of leaks.

For a screen, well, enclose that as well. You can do wonders with epoxy and fiberglbutt. At the very least keep it out of sal****er spray.

I am considering making a demo for this, mounting it at 30 meters depth below water; have a little window, webcam and ethernet link to the world. Hey, it may even run a clbuttic os with an emulator.

The project would cost around $900, 150 of which are for waterproof cables.

Step 1 is to establish a common ground point on the ship. This should include the engine, keel, battery negative, and all safety gound like sinks, stoves, gas pipes etc.

If you attach it to the hull other than at a keel-engine point you must have it thoroughly attached at many points.

If you attach this ground to AC ground (not AC neutral, ever) you must put a 30mA current fuse on it.

For a large ship you need to use something like 8mm cables for this.

Then you add anodes . The whole idea of anodes is to lower the potential of the negative bus by a few millivolts relative to the salt water surroundings, and have something else than gets corroded.

Many ships have active anodes (where they are force-fed around 200 mV) when the engine is running.

The idea of a GPIB bus in a salt mine gives me jeebies.

-- mrr