Run from thumb drive

[Douglas Pollard]

  Hi all, I am using Lubuntu   ( Navigatrix)  on a computer to navigate 
a sailboat with.  At the present time I have a laptop for navigation 
that I do not use on line and I have one that I use on line. I am afraid 
that my navigation computer might be compromised and cause me to run up 
on top a coral reef. Home file is incripted. I am being told that IF I 
use the program running off a thumb drive that it will be safe from 
compromise because it can't be written to?    What do you guys think 
about this does it make sense. Doug