The Toughbooks are probably the only "hardened" computer form a large commercial
vendor. Pricey, but if you look into the design they have done things like use shock mounts on the drives--which ordinary laptops just don't do. That difference could prevent you from losing data, or losing a drive, or needing to reinstall software
, on a day pounding through a chop.
Or, you could save a lot of money
using a cheaper laptop with a shock-mount, a foam pad under it, etc. It won't be easy to find one that is spray-resistant, etc. the same way though, but that's a question of how careful you can be with it, versus your budget
Putting a conformal coating on computer boards is not as simple as it might sound. Once you coat them, you change the electrical
characteristics of everything (mainly capacitance, I'm told) and that can affect how it will operate, if it will still operate. And it will affect heat transfer, etc. If you can afford to toss the computer out if it doesn't work--go for it.
But I don't think a desktop has any place aboard the boat, given today's laptop prices AND the ability to pull it off the boat, either to use a shore connection, or secure the laptop off the boat, etc. Among other things the whole laptop--even the processor, if you've bought one with a "mobile" type--is designed to use less power, and that's a good thing on a boat. With low end desktops taking 200W and many selling with 350-400W suppies, versus laptops that run on 40-75W, there's a tremendous power consumption
difference. And that's without the power consumption
of the desktops' additional display.