Ubuntu :: Setting Up Remote Administration On A Distant Machine?

I'm try to assess the viability of of setting up remote administration on a distant machine. Just for background, the computer I wish to administer is located on a boat in Southern Ireland while I'm in SE England. Sadly, the the boat operator is a far better fisherman than computer user and every now and then some rogue sensor numbers get captured by the boat's computer and these eventually need operator intervention. Anyone who has tried to talk a non PC literate user through correction routines over a dodgy mobile telephone while the said user is trying to operate mouse/keyboard in an Atlantic swell will appreciate the problem.

However, there is a fairly good mobile phone broadband signal available in the area so I was wondering if there was anyway I could set up a point to point connection with the boat over this medium. That would allow me to administer the machine remotely.