Hi! I am a major cruiser, and my husband and I like to go on a cruise once a year (we're doing Hawaii in 2013). We also travel a lot overseas, especiall to Europe. That said, here are my thoughts.
For a vacation to Europe, I think a Chanel bag is great and I take mine to places such a Paris, London, etc.
However, for a cruise, I do not. And here is why:
Most of the time when you are on a cruise, you are on an excursion during the day and you are a tourist. For a Mediterreanean cruise, one day, you may stop in Rome, and you will see the Coliseum. For day excursions which I am sure you will go on, I like to always wear a crossbody bag to be hands free. I also always carry a bottle of water and disposable wet wipes to wipe your hands. Also bring along a paper tissue pack as bathrooms are not always what you think. And of course, you need to bring the usual wallet, passport, and camera. Because of all this, I like a crossbody, and my bag of choice is a Longchamp crossbody nylon tote. Nearly everyone in Paris has a Longchamp, so it's simple yet chic.
For evenings on a cruise, you will most likely be walking around on the boat and having dinner at the boat. My first couple of cruises, I brought along my Chanels, but then, I only "dressed up" for dinner, which is literally 1.5 hours. What a waste of effort to carry a bag for 1.5 hours. And after dinner, my husband and I go right back to our room and change into more casual clothes and walk around the boat.
So... to me, for a cruise, I stopped bringing my Chanels as I never used them. Such a waste of luggage room.
And to be honest.. there is nothing worse than a tourist at a touristy site wearing a Chanel. It looks like the person is just trying to flash their bag. Putting it in terms we can relate to in the U.S.... it's like wearing a Chanel to Disney World or Busch Gardens... totally silly in my opinon.
That's my opinion based on my experiences.
If you had a lot of "formal night out", sure, it would be fine. But you should plan on a bag for the day. Seeing Rome or London or Monaco during the day, especially at tourist attracations like the Eiffel Tower, Buckhingham Palace, wearing a Chanel is goofy looking to me. Everyone knows you're a tourist, and to me... there is nothing worst than visting a tourist attraction with a Chanel bag. I have seen women at the Eiffel tower with a Chanel bag wearing high heel pumps... so ridiculous. And they are impressing no one, but looking out of place.
Of course anyone can wear a Chanel at any place, but it's all about looking chic for the environment you are in, and when you're a tourist... a nice crossbody bag is perfect. Look into Longchamp if you are not familiar.
Plus... you really need to wear a bag to carry stuff as I mentioned earlier... bottled water, moist wet wipes, pocket kleenex. These are musts when travelling in Europe.
Just my opinions. I hope this was helpful.
And you will LOVE the cruise. Have a great time! Get those cruise t-shirts on board the ship. I love them... cheap price, great quality! A cheap but lasting souvenir.