Originally Posted by Mike M
Having a "photocopy" of your passport may shorten the time it takes to get a replacement by a day or so but it is worthless for transportation or even as a source of identification.
If you don't have your actual passport you will spend a couple of days wherever you are stuck before you fly home. It all depends on how long it takes the U.S. Consulate to issue a replacement or temporary passport. That is if there is even a U.S. Consulate or Embassy where you are.
There are risks to carrying your passport onshore and there are risks if you don't. The choice is yours.
If I'm going for any extended tour I take my passport with me.
On most ships today, if you miss the ship we first open your safe and look for your passport. If it is there, we turn it over to our Port Agent before we depart. He is then responsible to wait for you on the pier (or find you in the hospital / police station), hand your passport to you, and arrange transport to our next port.
This saves everyone a great deal of trouble, guarantees that your passport will not be lost or stolen, and gets you safely back to the ship.