They are small for 5, but we have had great fun & even had a weekend over to the IOW in her with all our kit for over night stay, wetsuts, water skis, the lot. The kids tend to fight to sit right up front on the dry bags
2 on the Jocky seat & 2 on the box or one on the tubes & one on the box works for us
You will get wet but then its a small rib & great fun!
I have gone & bought a 6m ribeye with all the seating you could want but will not be selling the SR4 as for me she is just sutch fun for little money & it will be interesting to see which gets used more