I worked on a project years ago for the US Navy. At the time the average warship had something like 5 tons of paper documentation on board so they can do wartime repairs at sea if necessary. But 5-tons of paper docs are risky on a warship since they're combustable and easily destroyed.
Putting all these docs in digital form reduces the weight and risk (doesn't burn and easily replicated). Having that information available via an iPad, iPhone or other portable tablet device would be very handy, indeed.