Swimming at odd hours

Hey everyone! This is my first forum question, about nutrition and rest, hopefully in the right thread. At the end of the week I'll be swimming in a 24h team marathon. In short, 8 team members swim 30 minutes in 6 cycles during 24h. My scheduled entering times are 3.30pm, 7.30pm, 11.30pm, 3.30am, 7.30am and 11.30am. The team that covers the most kilometers wins. What I'd like to know is: what would be a good food strategy in the 3.5 hours I have between events, especially before and in between the last events when I'll be dead tired from lack of proper sleep? sleeping, no sleeping, how much? any other advice is much appreciated! Many thanks. Adrian