What I always do is make copy's of your travel documents, keep the original in the cabin safebox and carry a copy + original driver license for excursions.
But.... if for some reason you mis the boot and have to travel to the next port
if that port stay in a other country, then travel by airplane you can forget it there is no way. Although sometimes you can be lucky and apply a travel document for a few day's from customs on the airport. If you decide to carry the original documents and your afraid someone will stolen or lose then I would carry all the travel docs in a little bag on a cord around your neck and in your shirt.

By the way for Europian in Europe are a driver license or ID card enough as travel doc.