Snacks are the same as at home - fruit, chips, cookies, crackers, dip, cheese. We also usually have a bag of raisonets around.
For more substantive food, we have found that fajitas are perfect for the boat. We buy boneless chicken on sale, clean up the meat and put it in a ziplock freezer bag with appropriate spices and marinade, then put it in the freezer. When we are heading out, we pull it from the freezer and put it in the reefer on the boat to thaw. We also cut up peppers and onions and put them in a seperate bag with seasoning. When it is time to cook, the peppers and onions go in tinfoil puch on the back of the grill while we cook the chicken, also on the grill. When chicken is done, we chop it up, then put it out with the cooked veggies, cheese, hot sauce, etc. Right before serving, we heat flour tortillas right on the grill until they start to puff up. Easy to prepare, easy to cook, and very little clean up.
Along a similar vein, if we are making lunch for a group, we make salad or buy a precut bag, put that in a large bowl, add either leftover cut up chicken or chop up some turkey sandwich meat, add other veggies depending on what we have on hand, add some shreaded cheese, add dressing of choice, mix it all up, then put it out with fresh flour tortillas so everyone can make their own wraps to size.
Tortillas are great for the boat - both for the above reasons, and becuase they last longer than regular bread. Hmmm, I'm getting hungry.