As accommodations tend to be quite cramped on most ships, especially on expeditions, it is best to pack lightly. Bring only what is essential.
β gloves: wool, plus a pair of waterproof ones
β socks: wool or polypropylene
β knee-high rubber boots
β wind and water-repellant parka
β waterproof pants
β sweater (wool or polartec)
β day pack
β camera, plus extra digital card or film, and batteries
β seasickness remedy
β any special medicine you might need
It is best to dress in many thin layers, instead of a few bulky ones. Layering creates air pockets that keep you warmer, and can be peeled off or put on as to suit your comfort level, thus preventing sweating. Only cruise ships will have a shop where you can buy chocolates and other comfort foods. If you absolutely are going to be craving something, bring it along. Also check to see if drinks (e.g. soda) is included in the price of the excursion and/or if it is available on board. Also ask if beer, wine and other liquors are allowed. If you are on a cruise, you may need formal clothes too.
Upon re-declaring her independence at age 29, Lorraine Caputo packed her trusty Rocinante (so her knapsack's called) and began...