On my vessel, I have a Bose portable unit that holds, plays and charges our IPOD. I can keep it below or take it up on deck to enjoy, running on its internal battery. The battery in the unit runs playing about 8 to 10 hours so it could be topped up on land or via a small inverter aboard. It has a remote so I can change volume, on/off or what I am listening to without being right at the unit.
The Bose product is a bit pricey but the quality is terrific. I am sure there is something similar in a lower priced product (so if lost to theft) it would not be so painful. I work in OR's and the docs have little ones they bring in to use while they do surgery....pocket sized and not a big investment. Walmart or Best Buys should be your next stop to scope out options.
Have a great trip!!
Leslie
S/V "Tango", CR 34
Kent Narrows, MD