Other crew members. I'm not saying to be weary of them when they're holding a knife, no. You have to remember you will have to be out in all sorts of weather and that you share the same living spaces with everyone else. Roughly nine months out of the year you'll be on a boat. That's a long time to avoid getting sick from somebody. I always took some basic over the counter (OTC) medicines with me to combat anything I may come in contact with; sinus, allergy, flu, etc. Lines and wires.