Here in Britain, moisture is the biggest problem with on-board computers, so much so that I've bought a 'rugged' type for the main navigation computer. Next year I intend blue water cruising, once we get to tropical climates I anticipate that heat is going to be the enemy, not just for the computer but for other equipment that contains computer chips and memory modules. Much of the equipment is contained in the 'dash' which does have ventilation slots but they look inadequate to me. I think I'm going to look at installing some big fans at the base of the dash (with filters) to draw in colder air from near the deck even if this means that the pilot house will be a couple of degrees warmer. Anyone know where I can get fairly quiet fans that can handle large air flows? Paige