T&T: nav computer failure

[Chester Brummett]

The navigation computer has just failed.  I made it home from Bahamas before
total failure; before then, multiple restarts to get it to boot.

Dedicated PC, purchased from and "marinized" by a company that specialized in
marine displays and computers.

The extent of the "marinization" that I could determine was extra clamps and
wire ties to better secure the cables, and hot-gun glue on all connectors.

Extensive troubleshooting, the mother board had failed.  Memory, computer
chip, power supply, hard drive-- all still work. Evidence of corrosion on some
external connectors on the mother board.  Of course, this particular mother
board is no longer manufactured.  Special form factor to fit a shoe-box size
chassis.

Unit is 4 1/2 years old.  Installed in a closet shelf in forward cabin, driest
place I could find on the boat.  Added fan to discharge hot air, so overheat
should not be an issue.  Keep a dehumidifier operating in the boat when not in
use.  Apparently humidity and corrosion got to the unit (my guess).  Doubt it
is worth further attempts to repair.

My questions:

Knowing that these circuit boards were designed for the home - office
environment, is 4 years about the life that one should expect out of a PC when
permanently mounted on a boat?

Is the marizination done by any of the specialty houses worth anything?

Since my carrier was in military electronics, I know that conformal coating
unless done by experts as an expensive multi-step process (chemical cleaning,
drying, masking of connectors and switches, application of the conformal coat
and drying, etc), may do more harm than good.  I doubt any of the houses that
advertise conformal coat as an after-manufacture upgrade are going through the
steps to make it effective; rather just a "fell good" advertising ploy.

A redundant system in the same chassis (I think) would provide little added
overall reliability, if the failure mechanism is more related to environment.

What is the solution for system reliability?  Go with a low-cost computer and
carry a full spare computer, vacuum packed?  Or (considering the continuous
advance in technology) just plan to replace every three years?

I also have Furuno VX2 system, thus have a second chart plotter available, but
like the ENS (running RosePoint Nav CE) for the added features and the ability
to run raster charts.

I teach Piloting and Advance Piloting in the US Power Squadron, of course the
overall best backup is still paper charts and the knowledge to use them.  But
the electronic nav system is sure nice to have.  It spoils you to the
convenience.

Chet
DeFever 49 CPMY, Cygnet
Daytona Beach, FL