It would have to be one of the pontoons but I'm pretty sure that isn't what you mean.
From what I think I know I wouldn't expect to get much more than a 7' beam in an 18' boat. And the front deck is likely to be narrower. But, I could be (and often am) all wrong and it will be interesting to see what folks come up with.
It is rated for 11 people. I've had 12 on board once. The 3 on the front were 1 small woman, 1 medium woman, 1 medium sized man. 2 could fish up there no problem. Beam is 8'