Yup, I hear 'ya. Hips tend to go right through the foam to hard surface underneath. On my Grady, I was having the interior cushions re-done in vinyl so I had the shop use a medium-hard density foam in 4". I tried out a few different foams by actually laying on them. In a previous boat, whose cushions were in good shape, I added a memory foam mattress topper. I cut it (electric carving knife is the best tool for the job) to the exact dimensions of the v-berth, then took two top sheets and sewed them into a big "pillow case" to fit the mattress topper. I closed the "open" end with velcro. Wonderful night's sleep!!! In that boat, we left the berth setup as a bed all the time. But on the rare occasion we wanted to use the v-berth to sit, we could just roll the mattress topper up and secure it like a sleeping bag with string around it.