As a daytripper, I don't carry a lot in my kayak--just the things I need for the day, in addition to a change of clothes, safety stuff, etc. So, there is a lot of empty volume left over in the bow and stern compartments. I've always been keen on having additional flotation in my boats; thus I filled up large volumes of my wooden CLC Patuxent with closed-cell styrofoam when I built it. For my Epic 16X, I've found that empty plastic Tidy Cats cat litter containers fill up unused bow and stern volumes nicely, and weigh practically nothing. They come in various sizes, so one can somewhat customize how you fill up your boat.