Zombies can't seem to swim all that well, so floating in the water should work pretty nicely, right? It's a great plan, but perhaps you shouldn't have waited until the outbreak to finish your "floating fortress".
BTW, Me and my friend found a bug. The zombies only go for the monkey about 1/3 of the time . At one point, my friend threw a monkey, I kept shooting, the zombies (ATLEAST 30 FT. away), pass the monkey, get me down, and kept hitting me while I was down. I feel this is a rather important bug xD
Little did the rest of the group know, Richtofen had intentionally lead them to the sewers, due to having no more use for them. He needed to kill them off...