I take a backpack to most places I go on vacation. I thought that it would be handy to have one on the cruise also. I was thinking that it would be good to take on the excursions to carry mask and snorkel, maybe a towel, small camera ( I have digital SLR also), wading shoes, sunscreen, dry clothes, etc. My question is: what do you use to carry stuff on excursions AND what do you carry? I know that you can't carry food off of the ship. I like to be prepared. I would rather have it and not need it than to need it and not have it. .